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diff --git a/.gitattributes b/.gitattributes new file mode 100644 index 0000000..6833f05 --- /dev/null +++ b/.gitattributes @@ -0,0 +1,3 @@ +* text=auto +*.txt text +*.md text diff --git a/38036-8.txt b/38036-8.txt new file mode 100644 index 0000000..b7061de --- /dev/null +++ b/38036-8.txt @@ -0,0 +1,3837 @@ +The Project Gutenberg eBook, Electricity for the 4-H Scientist, by Eric B. +Wilson + + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + + + + +Title: Electricity for the 4-H Scientist + Idaho Agricultural Extension Service Bulletin 396, June, 1962 + + +Author: Eric B. Wilson + + + +Release Date: November 16, 2011 [eBook #38036] + +Language: English + +Character set encoding: ISO-8859-1 + + +***START OF THE PROJECT GUTENBERG EBOOK ELECTRICITY FOR THE 4-H +SCIENTIST*** + + +E-text prepared by Kevin Handy, John Hagerson, Matthew Wheaton, and the +Online Distributed Proofreading Team (http://www.pgdp.net) + + + +Note: Project Gutenberg also has an HTML version of this + file which includes the original illustrations. + See 38036-h.htm or 38036-h.zip: + (http://www.gutenberg.org/files/38036/38036-h/38036-h.htm) + or + (http://www.gutenberg.org/files/38036/38036-h.zip) + + + + + +Idaho Agricultural Extension Service +Bulletin 396 +June, 1962 +T-1 + +ELECTRICITY FOR THE 4-H SCIENTIST + +Safety +Uses +Economy + + + + + + + +Division I +4-H Electric + +University Of Idaho +College of Agriculture + + + + +HOW TO USE THIS BOOK IN FULFILLING THE GOALS OF THE 4-H ELECTRIC PROJECT +FOR THE FIRST AND SUCCEEDING YEARS + + +The minimum goals for credit in the 4-H Electric project vary according +to the 4-H member's age and the number of years he or she has taken the +electric project. For example, if you are a 4-H member beginning the 4-H +Electric project at the age of 10, you will not be required to earn as +many credit points as a 14-year-old 4-H member beginning the 4-H +Electric project. However, if you are a 12-year-old in your second year +of electricity you must earn as many credit points in that year as a +14-year-old does in his or her first year. + +Each lesson or goal has been designated a certain number of credit +points. These are shown near the title of each lesson or goal. You +decide on the lessons you want to study, list them, and add up the +credit points. + +For a full year's 4-H project credit, the total of your credit points +should be at least as many as shown in the following table: + +Examples of reading the table below are as follows: (a) An 11-year-old +member is required to complete 13 credit points the first year, (b) A +14-year-old is required to complete 17 credit points his first year, (c) +A 14-year-old taking the electric project for the third year must +complete 16 credit points that year. + +We recommend that, if you are taking the 4-H Electric project, you start +with the first lesson in the book and go on through to the back of the +book in advanced years. But you may skip the less important or less +interesting parts so long as you learn the basic lessons. A way to find +out whether you know the basic lessons is to read them through and try +to answer all questions under the heading "What Did You Learn." If you +can answer these questions you may not wish to spend the time doing the +things listed under "What To Do." + + Minimum Number of Credit Points Required for Each Year's Work in + the 4-H Electric Project + + 4-H Member's| 4-H Member's Year in 4-H Electric Project + Age | + | 1st Year | 2nd Year | 3rd Year | 4th or + | | | | Later Years + 10-11 | 13 | 15 | | + 12-13 | 15 | 17 | 19 | 20 + 14-15 | 17 | 19 | 21 | 21 + 16 & over | 19 | 21 | 21 | 21 + + +This system of credit points makes it possible for you to do the things +you want to do with electricity and get credit for them in the 4-H +Electric project. + + +4-H Electric, Division I + + + + +TABLE OF CONTENTS + + + Lesson Credit Page + Number Title Points Number + How to Use This Book 1 + B-1 Getting Acquainted With Electricity 3 2 + B-2 Tools for Electricians 4 7 + B-3 Rewire a Lamp--Be a Lamp Detective 3 11 + B-4 Make a Trouble Light 3 15 + B-5 What Makes Motors Run 5 18 + B-6 Taking Care of Electric Motors 3 23 + B-7 Reading the Electric Meter 4 26 + B-8 Ironing is Fun 3 30 + B-9 Let's Be Friends With Electricity 2 35 + B-10 How Electric Bells Work--For You 3 39 + B-11 First Aid for Electrical Injuries 2 43 + B-12 How Electricity Heats 3 47 + B-13 Mysterious Magnetism 2 50 + B-14 Give Your Appliances and Lights a + Square Meal 2 54 + B-15 You Can Measure Electricity 4 58 + + + + UNIVERSITY OF IDAHO + COLLEGE OF AGRICULTURE + AGRICULTURAL EXTENSION SERVICE + Eric B. Wilson, Extension Agricultural Engineer + 1962 + +Published and distributed in furtherance of the Acts of May 8 and June +30, 1914, by the University of Idaho Extension Service, James E. Kraus, +Director; and the U. S. Department of Agriculture, Co-operating. + + + + +LESSON NO. B-l + +Credit Points 3 + +GETTING ACQUAINTED WITH ELECTRICITY + + +Electricity serves you best when you understand how it works and use it +properly. As a 4-H member, you should know about electricity and help to +show others the way to obtain its tremendous work-saving benefits as +well as how to use it with safety. + +A good way to think of electricity is to compare it with water. It acts +a lot like water. However it is made of tiny parts of atoms called +electrons. When there are more than the normal number of electrons in +anything, it is said to be negatively charged; when there is a shortage +of electrons, it is positively charged. As water flows downhill, +"seeking it's level," electrons flow from negative to positive, seeking +to "balance" the charge. + + +Electrical Conductors + +Even if you're never going to repair a lamp or make a chick brooder, you +should know about conductors and insulators. This is because you happen +to be a fairly good conductor of electricity. Electricity will pass +easily through you to other conductors--the ground, for instance. When +this happens you may get a shock, burn, or serious injury. But it +doesn't ever have to happen, if you learn to understand your friend, +electricity. + +Silver, copper, iron, aluminum and many other metals are very good +conductors. Water, acids, and salts are too. Electricity passes over or +through them very easily. Like water pipes, the larger the conductor, +the more electricity it can carry. When conductors are too small for the +amount of electrons trying to move over them, they get hot, melt, may +start fires. That's why wire size is important. + + +Electrical Insulators + +Insulators are the opposite of conductors. Electricity has trouble +passing through some materials. Rubber, most plastics, dry wood, oils +and glass are some of the good insulators. It's the amount and kind of +insulation that counts. If it has enough force, electricity can pass +through just about anything--even jump gaps! + +Electricity, like water, flows along the easiest paths. It is always +trying to get to the ground. The earth attracts it. It stays on the +wires unless a person, a wet branch, or some other conductor gives it a +path to the ground. Do not touch any wire which might be carrying +electricity. + + +Play It Safe + +If you should touch a "hot" wire accidentally and are standing on a dry +piece of wood, the conducting pathway to the ground is not good and the +electricity may keep running along its wire. But do not touch some other +conductor with another part of your body. This would complete a circuit +through your body and would be very dangerous. Always make sure there is +plenty of good insulation material or plenty of distance between you and +anything which might be carrying electricity. + +Remember, too, insulation is of little use when it is wet. Dew, mist, +rain, condensation, a damp floor can change the whole picture. If you +understand electricity and how it acts, you'll be safe enough, because +you won't take chances or expose yourself to injury. + + +Electrical Terms + +_Alternating Current_--Usually referred to as "AC," alternating current +is current which reverses its direction of flow at regular intervals, 60 +times a second. + +_Direct Current_--"DC" current flows only in one direction. Battery +current is DC. + +_Ampere_--Amperes are units by which the rate of flow of electrical +current (electrons) is measured. An ampere is 6.3 billion electrons +passing one point in a circuit, in one second. This compares with the +way the flow of water is measured in gallons per second. + +_Volts_--A volt is a unit to measure the tendency of electrons to move +when they are shoved. Voltage is the amount of "push" behind the +electrons. It's like water pressure in a pipe. Home power lines carry +115 volts (110 to 120 volts). For appliances such as electric stoves, +washers and driers, a second 115-volt line should be added, giving 230 +volts (220 to 240 volts). + +_Watts_--Watts equal volts times amperes. Light bulbs, electric irons +and other appliances are usually marked with the voltage they require +and the number of watts. + +_Kilowatts_--Your electric bill usually reads in kilowatt hours. A +kilowatt is 1000 watts. A kilowatt hour equals 1000 watts used for 1 +hour. One kilowatt equals about 1-1/3 horsepower. A kilowatt is usually +indicated by "kw" and a kilowatt hour by "kwh." + +_Circuits_--A closed circuit is one in which the electricity is flowing, +lighting a light, running a motor, or some other appliance. The circuit +runs all the way from the place the electricity is being generated to +your home, through the appliance or light bulb, and back to the +generator. + +Circuits are opened and closed by switches. When the circuit is opened, +the electricity stops at the switch. Before working on a switch, socket, +fuse, or any part of the wiring be sure to open the main switch. The +main switch is usually at the fuse box or near it. Appliances should be +disconnected when you work on them. Everyone in the family should know +where the main switch is so it can be pulled in case of accidents, fire, +flood, or windstorm damage. + +_Fuses and Circuit Breakers_--These are the safety valves of your +electrical system. The different electrical circuits in your home are +meant to carry only certain amounts of electricity. Some carry only 15 +amps, others can carry 20 or more. They are marked to show capacity. + +When a fuse burns out or a circuit breaker opens, look for an overload +of lights and appliances on the circuit before you try to replace the +fuse or close the circuit breaker. Without these safeguards, the +overloaded electric line will heat up and may start a fire. Even if no +fire starts, electricity will be wasted and the homeowner will be paying +for electricity that's doing no good. + +Remember: If you ever have to replace a fuse, pull the main switch +first. Keep a flashlight handy in your house. It seems that fuses +usually blow at night, and it doesn't pay to stumble or fumble around +electric wires in the dark. + + +WHAT TO DO: Make A Circuit Board + +So that you can show others how electricity travels from here to there, +and how it behaves under different conditions, make an electric circuit +board. + + + _Materials Needed:_ + + Piece of 3/4" board about 4" x 6" + l-l/2-volt No. 6 dry cell battery + Two pieces of bell wire, each 24" long, one black, one white + Two 10-penny box nails (3") + Three 3-penny box nails (1") + Two small screws or carpet tacks + Two 2-inch rubber bands + Two miniature sockets with solder terminals + Two l-l/2-volt flashlight bulbs + + _Tools Needed:_ + Ruler, pencils, hammer, pliers or vise. + + + +_Making the Board:_ + +1. Lay out the board with a pencil and ruler as indicated in Figure 1. + +2. Bend the three-inch nail as shown in Figure 2, using pliers, vise and +hammer. + +3. Pound the one-inch nails into the board for a half-inch at points A, +C, and D. Use the three-inch nail to make a hole a half-inch deep at B. +Put the crank nail in this hole and pound in a little farther. Attach +the lamp socket brackets at E and F. Stretch the rubber band as in +Figure 3. + +4. Lay out the electricity path, the circuit (Figure 3). Use the black +wire for the positive side of the circuit (the center pole of battery). +Twist it around the switch crank B, and the center pole of battery. Run +another piece to the outside terminal of bulb socket at E. Run white +piece to negative pole of battery from the other terminal at E. + +[Illustration: Figure 1 (Circuit Board)] + +[Illustration: Figure 2 (Switch)] + +5. Close the switch. The rubber band should hold the switch nail tightly +against nail at C. Does the bulb light? __________ If it doesn't, check +the connections. + +Now you have a circuit--a closed circuit when the electricity runs all +the way from the positive pole to the negative pole. The black wire is +the hot side, the live wire, because it carries the full load of the +battery up to the bulb. + +Remember, battery current is direct current, DC. In the case of +alternating current, AC, such as most homes and buildings use, the +electricity flows in first one direction and then the other. + +[Illustration: Figure 3 (Closed Circuit)] + + +Parallel Wiring + +To make this circuit hookup, attach another white wire to the negative +pole of battery and a terminal of the second flashlight bulb. Run a +black wire from the other terminal to the switch terminal at C (Figure +4). Close switch. Both bulbs will light. + +Trace the circuit. Electricity is going equally to each bulb, the same +amount that went to the single bulb. The difference is that the battery +will last only half as long. It's like a pail of water with two open +spigots. The pail empties twice as fast as it would with just one spigot +open. This type of wiring is called parallel wiring. If one bulb is +unscrewed, the other will stay lit. + +[Figure 4 (Parallel Wiring)] + + +Series Wiring + +To do this, run the negative wire to one terminal of the second bulb and +attach a wire from the other terminal to a terminal of the first bulb. +The other terminal connects with the switch at C (Figure 5). This is +series wiring. If one bulb is unscrewed, the other will fail to light +because the circuit is broken for both. Anything that breaks the circuit +has the effect of opening the switch. + +[Illustration: Figure 5 (Series Wiring)] + +Show there is a circuit through the bulb by screwing and unscrewing it. +Also, "jump" the socket by running the wire from C to the other terminal +of the bulb at E while it is unscrewed. Bulb at F will light. Trace this +circuit. + + +SUGGESTED DEMONSTRATIONS + +Using the Circuit Board, you can give many demonstrations of the way +electricity flows, works and behaves. + + +Water And Electricity + +To help others understand electricity better, draw a water system on an +electric circuit board paralleling the circuit. For the battery show a +water tank, pipes instead of wires, faucets instead of switches. +Somewhere on the board paste a comparison of electrical terms with terms +used in describing water, such as the following: + + Wire equals Pipe + Volts equal Pressure + Amperes equal Rate of Flow - gallons per second + Watts equal Pressure times Rate of Flow + Switch equals Faucet + Current equals Flowing Water + + +Show how to figure the wattage that a circuit protected by a 15 ampere +fuse can handle. Do it with actual things or cut-out pictures of light +bulbs, irons, toasters, coffee-makers, etc. + +You know that Amperes times Volts equal Watts. If the voltage is 115, a +15 amp circuit can handle 115 volts times 15 amps, or 1725 watts. + +The name plates on electric motors indicate the amperage at full load. +You can convert this to watts, of course, by multiplying amperage by the +line voltage. Motors require an additional amount of electricity when +they start. You need to allow for this fact, so fuses will not blow or +circuits trip when a motor is turned on. You will learn more about this +when you study electric motors. + + +For More Information + +Your leader has many other sources of information about electricity and +demonstrations you can perform. Ask him. Also, libraries have many books +about electricity and its history, which are very interesting and +useful. Maybe you can find an electrician, someone from your power +supplier, or an equipment dealer who will talk to your club on +electricity or electrical safety. + + +What Did You Learn? + +(Underline the correct answers then discuss in the group.) + +1. In a water pipe system water flows. In an electrical circuit +(electrons) (atoms) (charges) flow. + +2. Electricity or electrons flow (easier) (harder) (about the same) in a +conductor than in an insulator. + +3. Rubber is a good (conductor) (insulator) (ground). + +4. The most common material used as an electrical conductor is (glass) +(silver) (copper). + +5. The unit of electrical pressure or push is the (ampere) (volt) +(watt). + +6. The rate of flow of electricity is measured in (gallons) (amperes per +minute) (amperes). + +7. Volts times amperes equals (watts) (kilowatt hours) (alternating +current). + +8. A dry cell battery (stores) (makes) (uses) electrical energy. + +9. In a parallel circuit the electricity has (one) (two or more) (no) +paths to travel. + +10. In a series circuit with two bulbs and a switch the bulbs are +(brighter) (dimmer) (the same) as when they were in the parallel +circuit. + + + + +LESSON NO. B-2 + +Credit Points 4 + +TOOLS FOR ELECTRICIANS + + Who goeth a borrowing + Goeth a sorrowing + Few lend (but fools) + Their working tools + + Tusser 1524-1580 + + +Whenever a job comes up, it saves time and trouble when you have the +right tools and they are all where you can find them. Electrical work +takes some special tools and some everyday tools. + +If you have ever watched a good electrician at work, you've seen how +neatly he stores his tools in a box so every one of them is handy. When +a lineman climbs a pole, he has his regular tools in a holster on his +belt. Special tools are kept in a box in racks in the repair truck, all +ready for instant use. Wouldn't you like to have electrician's tools all +handy, ready for use, and know how to use them properly? + + +Basic Tools for Electrical Work + + +_Knife_ + +A good knife with a sharp blade is one of the most useful tools. A +camper's or electrician's type knife is probably best because it has +other useful parts besides the cutting blades--a screwdriver or punch, +for instance. Of course, you'll never use the cutting blades as a +screwdriver. This knife should be kept clean, dry, sharp, and free from +rust. Put a little oil on the joints from time to time. Remember, "Never +whittle toward you and you'll never cut yourself." + + +_Pliers_ + +A pair of electrician's pliers should be part of your kit. Wrap the +handles with plastic insulating tape. Even though you're not going to +work on "hot" electric lines, it pays to play safe. Later on, as you +learn more about electricity, you'll want a pair of needle-nose pliers +for the fine work. + + +_Screwdrivers_ + +You'll want a screwdriver which has true corners. A 4 to 6 inch plastic +handled screwdriver with a narrow blade is best. You'll probably need +more than one size to fit the various size screws you'll be turning. + +Screwdrivers are easily damaged if you try to use them as chisels and +pry bars, or use them in screw slots which are too large for the blade. + +You can be hurt by the screwdriver if you try to screw or unscrew things +you are holding in your hand. Keep your free hand away from the end of +the screwdriver. Place the work on a bench or where it can be handled +easily. + + +_Soldering Iron_ + +A good 100 to 250-watt electric soldering iron will be useful. Later on +you may want to buy a soldering gun, but unless you are doing a lot of +soldering it won't be necessary. A supply of resin-core electrician's +solder will be needed. Acid-core solder reacts with copper and in time +causes a bad splice. + + +_Tape_ + +Once it was necessary to use two types of tape on splices--rubber tape +with friction tape over it. Now there is a plastic tape on the market +which takes the place of both and has good insulating quality. It is +called electrical tape, or plastic tape, and resists water, oils (which +would damage rubber tape), and acids. You'll need a lot of tape in your +electrical work, so keep a roll on hand. + + +_Other Tools and Equipment_ + +As you go along in electrical work, you'll be adding tools and other +equipment, such as a trouble light and maybe an ammeter or voltmeter. +Other tools you'll want to add will be a Phillips screwdriver, open end +wrenches, a crescent wrench, small hack saw, hand drill and bits. + +You'll also be using some regular carpenter's tools such as hammers, +saws, and so on. Unless you use them frequently, you don't need to keep +them in your electrical kit. + +It's a good idea to start acquiring a supply of electrical +parts--lengths of wire, fuses, switches, sockets, plugs, and other items +that will come in handy. There are parts you can salvage from old lamps, +motors, and other equipment. Such a collection can be a real treasure +chest when you need a part in a hurry. But be sure to throw away all +faulty parts. + +[Illustration: Figure 1. Completed tool chest.] + + +WHAT TO DO: Build a Tool Chest + +To keep your tools always ready for use, a tool chest will be very +handy. It's the 4-H way to work. You'll be surprised how much easier it +makes a job when you have your tools, various parts and repair equipment +all in one place. You can make the chest (Figure 1) with a saw, plane, +screwdriver, pencil, ruler or carpenter's square, and hammer. + + +_Materials You'll Need:_ + +A piece of lumber 1" by 10" by 8 feet long. (1" lumber is actually only +3/4" thick--this is the thickness you'll be working with.) + +2 small hinges, with wood screws + +1 small hasp, with wood screws + +2 small handles with wood screws, or one large handle + +1 small chain, 10" to 12" long + +Some No. 6 penny finishing nails or wood screws about the same length + + +_Making The Chest:_ + +1. Cut your lumber into the following pieces: + +1 piece 10" x 18" for top + +1 piece 8-1/2" x 16-1/2" for bottom + +2 pieces 6" x 8-1/2" for two ends + +2 pieces 6" x 18" for front and back + +2. Lay out pieces as shown in Figure 2. + +[Illustration: Figure 2] + +Then, set up the two end pieces and nail to bottom section. Refer back +to Figure 1 as you go along to see that box is shaping up as shown. Nail +the front and back sections to the ends along the bottom. Wood screws +can be used instead of nails. + +3. Lay the top in place and attach hinges to the back side, about two +inches in from each end. + +4. Attach one part of hasp to the top, and the other part to front board +in center. Fasten the handles to each end. + +5. Attach chain to the top and front so the top will stay open when +chain is fully extended. + +Now you can invent your own improvements for your chest. You can paint +it, put your name on it, and your club emblem and name if you wish. You +can put a rack on the inside of the cover to hold your work sheets and +other booklets and materials. You can install special slots or straps to +hold each tool in its place along the sides of the box. Maybe you will +want to put some partitions in the box to separate various electrical +equipment such as wires, fuses, switches, and plugs. + + +_A Working Kit_ + +An accessory which you may want to add to your tool chest is an apron or +holster to wear when you are moving around on the job. An apron can be +made of a size of cloth about 18 by 20 inches. It should be folded up +from the bottom, and sewn to fit the number and size of tools you have. +Figure 3 shows such an apron. + +[Illustration: Figure 3. Apron.] + +You can make a lineman's holster in the same way, using plastic or soft +leather. Merely make belt loops by cutting on the dotted lines. A snap +fastener will hold the flap over the tools so they won't fall out. + +[Illustration: Figure 4. Lineman's Holster.] + + +Demonstrations You Can Give + +Show and tell others the proper handling, care and use of tools. + +Show and tell how to build an electrician's tool kit. + + +For Further Information + +Ask your power supplier or an electrician to tell the club about the +various tools of the electrician's trade and demonstrate them. Ask your +leader how to get exhibit material or information about electrical tools +and their use and then tell the club about them. + + +LESSON NO. B-3 + +Credit Points 3 + +REWIRE A LAMP--BE A LAMP DETECTIVE + + +[Illustration: The Line-Up Of Lamp Suspects] + +One of the duties of a law officer is to prevent crime. It's that way +with the lamp detective. You can become one. In the average home there +are lamps about to commit the crime of shocking people, starting fires, +and stealing electricity. Some are refusing to do their job well and +some are no-goods, sitting in closets or attics, doing nothing. You can +put these lamps to working again safely and well. Become the lamp expert +in your family. + + +What's In A Lamp? + +A lamp gives light for comfortable and convenient use in the home. It +consists normally of a stand, switch, cord, lampshade holder, and shade. +Some lamps have diffusing bowls which reduce glare and shadows. + +The most common fault found in an old lamp is in the cord, but sometimes +the switch or the wiring in the lamp is bad. Look over all the lamps in +your home and find the ones needing to be fixed. + + +WHAT TO DO--Rewire A Lamp + +Somewhere around your house you can probably find a lamp that is no +longer used or needs repairing. You can make it useful again and at the +same time learn how to wire a lamp. + + +_Materials Needed_: + +Tools: Pocket knife, small or medium screwdriver, and pliers +(electrician type is best). + +_New Lamp Cord_: For each lamp to be rewired, you'll need 6 feet of cord +plus the length of wire within the lamp stand. Lamp cord wire comes in +two sizes, No. 18 and No. 16 AWG (American Wire Gauge). No. 18 is +smaller than No. 16, but is adequate for most lamps. Cords are made with +surface coverings of several different materials: braided cotton, rayon +or silk, and molded rubber or plastic. Braided cord is decorative, but +rubber or plastic is easier to work with and is usually more desirable. + +_Switch_: If the switch is bad, get a new one. Socket switches are made +with push-through, turn-knob, or pull-chain controls. The pull-chain +type is seldom used on modern table or floor lamps. Your lamp may have a +separate push-switch in the base. In this case, get the same kind for +replacement. Some switches are "3-circuit" switches for use with high, +medium, and low-light bulbs. + +_Plug_: Plugs are made of various materials, mostly hard rubber or +molded plastic. Some have a shank or handle for better grasping. This +type is more desirable. The plug on the old cord may be good, and if so, +may be used on the new cord. + + +How To Do It: + +1. If the plug on the old cord is good and you plan to use it, remove it +from the old cord. + +2. Measure and cut a new lamp cord equal to the length of the cord +within the lamp, plus 6 feet. + +3. Pass one end of the new cord through the center of the plug. Strip 2 +inches of the fabric insulation off cord, or in case of a rubber cord, +split cord back two inches. Be sure no bare wire shows in long split +section (Figure 1). + +4. Use knife to strip insulation off wire for 3/4" on end of each cord. +Be careful. Don't cut yourself. Don't cut wires. Use a light touch, +slope the knifeblade and slice with knife edge away from you (Figure 1). + +[Illustration: Figure 1 (Ready to Wire Plug)] + +5. Twist exposed strands of each wire tightly to make a good conductor, +and place each conductor around its proper terminal in the direction in +which the screw tightens (Figure 2). + +6. Tighten screws on terminal posts. Pull cord until slack is out. Lay +aside until ready to attach to lamp. + +[Illustration: Figure 2 (Attaching Cord to Plug)] + +7. Remove lamp shade, shade-holder, bulb, and diffusing bowl, if there +is one. + +8. Separate the metal shell of socket from its cap by pressing on shell +at place marked "press," and pull socket from cap. + +9. Pull on socket body to get some slack in lamp cord. Loosen screws and +detach cord. Pull cord out through base of lamp. You can splice new cord +to the old one and use the latter to "string" the new wire. + +10. Pass the new cord up through the lamp base and socket cap, tie a +simple half-hitch knot in the cord to prevent strain on the terminals, +and attach wires to the terminals on the socket (Figure 3). If there is +likely to be any strain on cord, use an Underwriters' knot. Twist +strands and attach wire in direction in which screw tightens. + +11. Pull slack out of cord in lamp so that socket rests in socket cap, +replace shell and reconnect cap. Be sure the fiber insulator is in the +shell. You'll feel or hear a click when the notches in shell are locked +to the projections in the cap. + +12. Replace bulb, inspect carefully, and test. (In floor lamps where the +cord runs through the center post and out under the base, the cord will +last longer if it is fastened with tape so it doesn't rub edge of lamp +base when lamp is moved.) + +13. If the lamp has a porcelain socket, simply disconnect the wires at +the terminals, remove the old wire and connect the new one. + +[Illustration: Figure 3 (Socket and Switch Assembly)] + + +What Did You Learn? + +Underline correct answers then discuss in the group. (There may be more +than one correct answer.) + +1. The part of the lamp that usually wears out first is (the socket) +(the cord) (the plug). + +2. Lamps that waste electricity are those which have (bad wiring) +(frayed cords) (dirty shades or bulb). + +3. To unplug a lamp you should grasp (cord) (plug) firmly and pull. + +4. Wire in lamp cord usually comes in sizes 16 or 18. Size 16 is the +smaller (true) (false). + +5. In fastening wire around a terminal post it should go around in a +(clockwise) (counter-clockwise) direction. + +6. When the switch on a lamp is turned off, the electricity only goes as +far as (the wall plug) (the switch). + +7. An Underwriters' knot should be used (only when there is room for it +in the plug) (whenever there is likely to be strain on the cord, even if +you have to replace the plug with a larger one). + + +SUGGESTED DEMONSTRATIONS + +Show how to inspect a lamp and its cord. You might tie tags on the cord +and lamp at points of danger or failure--at the plug, wear points next +to lamp base, bad sockets. + +Demonstrate the process of repairing a lamp cord, socket and plug. + +Make a board display of the parts of the lamp socket showing cord +attached. + +Make a display of the types of lamp cords and plugs in common use. + +Using two lamps, one with clean bulb and shade, the other dusty, show +how the former gives more light. + + +For More Information + +Lamps have an interesting history. Look it up in your local library. Ask +someone from your power supplier or electric dealer to talk to the club +about the different kinds of lamps. Your leader has or can get +additional information on lamps, if you wish. + +[Illustration] + + +What Did You Exhibit + +What Did You Demonstrate + + + + +LESSON NO. B-4 + +Credit Points 3 + +MAKE A TROUBLE LIGHT. + + +A handy piece of equipment in the home and on the farm is a heavy-duty +extension cord with a shielded light and a side outlet on it. When you +want to work on the car or tractor in the yard at night, the trouble +light is better than a flashlight. You can use it both for light and as +an extension cord. It is safer than matches or a lantern, especially +around the garage or barn. + +It is easy to make a trouble light, and it gives you good practice in +electrical work. Of course you can buy one, but you wouldn't have the +fun of making it nor would it suit your needs. Trouble lights are not +for permanent use--they're for emergency use and to provide light or +electricity in places where they are seldom needed. When you find a +trouble light being used as permanent wiring, that's the place to +install an outlet. + + +What Size Cord? + +Choose the right kind of cord. What length will be best for your various +uses? A cord too long may be bothersome to use and store. What will be +the heaviest load you are likely to put on the cord, in amperes? Check +appliances you may want to connect to it. No. 16 wire can carry 10 +amperes safely for a distance of 50 feet, while No. 18 can carry only up +to 7 amperes for a distance of 40 feet. You'll want a "hard service" +cord, called S, ST, or SO-type cord by electricians. Junior hard service +cords, known as SJ, SJT, or SJO, are fine for lighter duty. + + +Cord, Plug and Guard + +A rubber-handled socket should be used for safety and to withstand hard +knocks. It should have a switch on it, preferably a push switch in a +recess in the handle. + +The connector or attachment plug should be of rubber or solid plastic +and have a metal cord grip fastened to it. This grip will hold the cord +firmly and prevent strain on the terminal connections. + +[Illustration: Finished Trouble Light] + +Get a good lamp guard. If the wire is too light, it may bend and break +the bulb when hit or dropped. For the lamp itself, get a rough service +lamp. An ordinary lamp won't last long with rough usage. + + +How to Make the Trouble Light + +_Tools Needed:_ + +Your 4-H electrician's kit or screwdriver, knife and soldering iron + +_Materials Needed:_ + +1. About 20 feet of 2-wire, No. 16 heavy duty (hard service) + +2. A rubber-handled socket with switch and a side outlet + +3. A shielded lamp guard + +[Illustration: Materials Needed] + +4. A good connector plug cap, preferably with a clamp-type grip for the +cord + +5. A rough service lamp bulb + +6. Solder and flux + + +_Steps to Take:_ + +1. Remove about 2 inches of the outer covering of cord at one end. + +2. Separate the wires and cut away the filler material. + +3. Remove 3/4 inch of the conductor insulation from the end of each wire +and tightly twist the strands together to form a firm conductor. Be +careful not to cut any of the fine wires. Ends may be soldered. + +4. Slide the plug in position on the cord. + +5. If there is no cord grip, tie the underwriters' knot (Figure 1). If +there isn't room enough, make an "S" loop by passing the wires around +the prongs before fastening them to the terminal screws as explained in +the next step. + +6. Loop the bare part of the wire around the screw in the direction the +screw is turned to tighten (clockwise direction). This will prevent the +wires from being forced out from under the head of the screw as it is +tightened. Now repeat with the second wire, wrapping it around the other +prong of the plug. + + +_Connecting the socket._ + +1. Separate the parts of rubber-handled socket (Figure 2). + +2. Prepare the other end of the cord as in steps 1, 2, and 3 above. + +3. Insert the cord through the rubber handle and socket guard. + +4. Tie the holding knot (underwriters' knot) as explained in Step 5. + +5. Connect wires to terminal screws and assemble the rubber-handled +socket. + +6. Screw in the rough service lamp and test your cord. + +7. Put the shielded lamp guard on the socket and tighten the holding +clamp until it is firmly in place. You are now ready to use or +demonstrate your trouble light. + +8. After you've made your trouble light, decide on a good place to keep +it where it will be handy for use. Loop it carefully and hang it over a +wooden dowel rather than a nail. It will last longer. + +[Illustration: Figure 1 Tying an Underwriter's Knot] + +[Illustration: Figure 2 Disassembled Light] + + +What Did You Learn? + +(Underline correct answer) + +1. A Junior Hard Service Cord is known as an (SO-Type) (SJO-Type) cord. + +2. You disconnect a cord by (jerking it from the socket) (grasping plug +and pulling it out). + +3. Brass sockets are unsafe because (they break too easily) (the exposed +metal can cause short circuits). + +4. Rubber-covered cord is safer for emergency cords than fabric because +(it will stretch) (it will insulate and protect the wires inside). + +5. In a trouble light (any kind of bulb will do) (a rough service bulb +is best). + + +Ideas for Demonstrations and Exhibits + +1. Show how to make your trouble light and a method of storing it. + +2. Show a safe trouble light, and an unsafe trouble light with danger +points marked. + +3. Show cutaway pieces of different types of cord. + + +For More Information + +Ask your power supplier, county highway engineer, police official or +leader to tell you about various types of portable emergency lights and +their uses. + + + + +LESSON NO. B-5 + +Credit Points 5 + +WHAT MAKES MOTORS RUN + + +What makes an electric motor run? Can you make an electric motor that +will run? Certainly you can, and by doing so you'll learn why it runs. +It won't be mysterious any more and you'll be ahead of all the millions +of people who use motors every day and never know why or how the motor +converts electrical energy into useful power. + +[Illustration] + + +Motors Are Magnets + +You know how one end of a compass needle always points to North. No +matter how you turn the compass, the same end of the needle always +swings to the North. The earth itself and that small compass are both +magnets (Figure 1). Each has a North pole and a South pole. Around the +poles of each there are magnetic fields, invisible lines of force that +attract and repel. + +[Illustration: Figure 1. The same end of the compass needle always +points to the earth's magnetic North Pole.] + +The N poles _repel_ each other and so do the S poles. The N and S poles +_attract_ each other. In other words, opposite poles attract; poles that +are alike repel each other. + +Lay 2 bar magnets on a table side-by-side. If both N poles are at one +end, they'll repel each other and almost flip around until there's a N +pole lying next to a S pole (Figure 2). + +[Illustration: Figure 2. Small bar magnets laid side by side move so +that the North pole of one is near the South pole of the other.] + +Now suppose we place one of the bar magnets on the table. The other, +we'll fix on a pivot so it can spin around. This one we'll move so its N +pole almost touches the fixed magnet's N pole. As soon as we release it, +the movable magnet will spin around so its S pole will be near the N +pole of the stationary magnet. That's an electric motor--almost. + +[Illustration: Figure 3. A movable bar magnet pivots so its South pole +is near the North pole of a stationary magnet.] + +It's not quite a motor because the rotating magnet will just move as far +as it has to in order to get the opposite poles together. You might be +able to cause the movable bar magnet to make turn after turn. You could +do this by turning the fixed magnet quickly end for end. This wouldn't +be very practical as a motor. + + +We Can Improve It + +If we could change the pole on one end of the rotating magnet just as +soon as it reaches the attracting pole, it could make a complete circle. +In doing that, the pole at the near end of the rotating magnet would be +repelled by the stationary magnet and pushed away. As soon as the +opposite end of the rotating magnet would come into the magnetic field, +it would be drawn to the stationary magnet. In order to keep the "motor" +running, we would have to constantly change the poles at each end on +every half revolution. + + +We Need An Electromagnet + +We can't reverse the poles on simple bar magnets, but we can on +_electromagnets_. We can make one by wrapping a wire several times +around an iron core to form a coil. This magnet will also have a N and a +S pole when connected to electrical current. The big difference is that +the poles can be changed instantly by reversing the current in the wire. + + +Switching Poles Automatically + +The rotating electromagnet will have to be connected to the 2 wires +through which we pass the current. Since it's rotating on a center +shaft, we can't have a solid connection. Instead we have to extend the +wires from the coil out along the shaft and let the electric contact be +made with brushes which touch the wires along the shaft. + +[Illustration: Figure 4. A rotating electromagnet changes poles as +contacts are made first one way, then the other.] + +This is a simple way to reverse the current in the coil of the +electromagnet. + + +Increasing Efficiency + +Instead of using only one pole of a stationary magnet, we can use both. +This is done by shaping the stationary magnet around the path of the +rotating electromagnet. This way we have the benefit of the attracting +and repelling forces from both poles. The effect is doubled. + +We can also wrap wires around this circular iron and make an +electromagnet of it. But when we wire this magnet we use no brushes +because we want the current to flow in one direction only. + +The stationary electromagnet is called the _field_. The rotating +electromagnet is the _armature_. + + +WHAT TO DO: Make A Motor + + +_Tools Needed:_ + +Pocket knife, hammer, vise (or 2 pairs of pliers). + + +_Materials Needed_: + + 1 roll of No. 24 enameled wire + 1 roll of electrician's tape + 3 - 4" (20-penny) nails + 4 - 2-1/2" (8-penny) nails + 4 - 3" brads (10 penny) + Wood board for motor base + 2 staples or 4 small brads + 2 tacks + 2 - 3 volt dry cell batteries (or a 6 + volt transformer). + + +Step No. 1-Armature + +Wrap about 1-1/2" of a 4" nail with two layers of tape. This will be the +shaft. + +The iron core will be made of two pairs of 2-1/2" nails. Wrap tape +around each pair with heads and points alternated. + +Center both pairs on each side of the shaft. Place them about 1" from +the head of the shaft nail. Wrap them together with two layers of tape +from tip to tip. + +Start at the shaft and wind No. 24 enameled wire to one end and back. +Then do the same on the other end. Always wind in the same direction. +Leave 6" of spare wire at start and finish. + + +Step No. 2-Commutator + +Scrape all insulation off the ends of the wire. Bend the bare ends back +and forth as shown. Lay them flat over the taped shaft-one on each side +of the shaft. + +Hold the commutator down with narrow strips of tape. Wrap tightly near +the core and at the opposite end. + + +Step No. 3-Field + +Make the core by bending two 4" nails in the middle at right angles. +Space the heads about 3" apart to form a horseshoe. Wrap together with +two layers of tape. + +Wind about 400 turns of wire around the center. Leave 4" of spare wire +at start and finish. Attach to wood base with staples at each end of +the wire. Small brads, bent over, will do just as well. + + +Step No. 4--Armature Supports and Brushes + +Scrape the insulation from the ends of two 6" pieces of wire. Tack +them to the base and bend them as shown to make brushes. + +Drive two pairs of 3" brads into the base about 3-1/4" apart and in a +line midway between the field poles. Wrap wire around the supports to +form armature bearings. + +Scrape insulation off ends of wire from the field. Connect one end to +a brush wire. + + +_Assemble As Shown_ + +Adjust the position of commutator and tension of brushes against it for +best operation. + +Take the armature off the motor and connect the commutator wires to a +dry cell battery. Test the polarity of each end of the armature with a +compass. Switch the connections on the commutator and test again. See +how the compass needle changes direction? + +With the armature still off, connect the field coil directly to the dry +cell. Test the polarity of each end of the field with the compass. How +can you reverse the polarity? Try it. It's easy. + +Reassemble the motor again and start it. Push the field poles slightly +out of alignment with the turning armature. What happens to the motor's +speed? Can you tell why? + +This time, push the field poles completely out of the way. Test the +polarity of the armature as you slowly turn it by hand. Do you see what +happens and why it does? + +Try to reverse the direction of rotation of your motor by reversing the +connections at the battery. What happens? Can you explain why? + + +Demonstrations You Can Give + +Make a display board showing the parts of the toy motor and explain how +each part works compared with the parts of a commercial motor. + + +For Further Information + +There are several other types of toy motors you can build. Your club +leader or power supplier can help you find information about them. + +1. Did your toy motor run? + +2. Did your motor speed up or slow down when you pushed the field poles +out of line? Why? + +3. What happens to the magnetic polarity of the armature when you turn +it slowly by hand and check it with a compass? + +4. How can you reverse the direction of rotation of your toy motor? + +Is there another way too? + +What is it? + + + + +LESSON NO. B-6 + +Credit Points 3 + +TAKING CARE OF ELECTRIC MOTORS + + +Through the magic of electric motors, much of our work is done faster +and better at lower cost than we could do it without the help of the +electric motor. People who use motors and treat them properly have much +more time for other work and for leisure time activities. A +1/4-horsepower motor running quietly and steadily hour after hour will +do the work of one man, and operate all day for about 5 cents without +tiring. On many jobs it will work without "supervision", turning on and +off automatically, as required. It does this on water pumps, in heating +and cooling units, and on fans and similar appliances. + +All that a motor needs to do its work is electricity and a little care. +Let's see what you can do to give proper care to motors in your home and +on your farm. + + +You'll Need + +A light oil (SAE 10) for motors of less than one horsepower and a +slightly heavier oil (SAE 20) for larger motors. See if you need grease +for cups which may be on large motors. If so, be sure you use +ball-bearing grease and not ordinary cup grease. Cotton waste or clean +rags will be needed for wiping off the motors, and a tire pump or vacuum +cleaner for blowing out the dust or dirt. + +[Illustration: Some motors have instructions for oiling on the +name-plate.] + + +WHAT TO DO + +1. First, make a list of all the electric motors that work for your +home. You may wish to make a separate list for your farm buildings. +You'll probably be surprised at how many there are. Don't forget the +sewing machine, the refrigerator, the freezer, the vacuum cleaner and +other small but important motors. Don't touch any motor that is running. +Disconnect them before you touch them. + +2. Make a motor service chart with columns headed: Use, Location, +Horsepower, Volts, Amperes, Service Required, Date Serviced and What was +Done. (See sample) Then list all the motors that require any servicing. +Some will have the instructions on the motor or appliance; the +instruction booklet that came with the motor or appliance will also tell +what servicing is required. + +_Step 1._ Plan the job. Start with the motors in the home. Then you can +care for the motors on the farm. + +_Step 2._ Be sure that any motor on which you are going to work is +disconnected. Then wipe the outside case clean with a cloth. If the +motor has openings in the end, use a vacuum cleaner to suck out dust, +dirt or chaff. A tire pump may also be used to blow out this dirt. If +you use compressed air, be sure the pressure is not high as it may +damage wiring inside the motor. Dust-proof motors should be used in +dusty or dirty places. + +_Step 3._ + +[Illustration: If there are oil holes, oil according to the +manufacturer's instructions.] + +If there are no instructions, remember a little oil goes a long way as +far as motors are concerned. Motors of less than one horsepower require +only 3 or 4 drops (not squirts) of oil every 3 or 4 months if the motor +is used frequently. Too much oil can damage the motor. It spoils the +insulation. + +If there are no oil holes or grease cups on the motor, it is probably +lubricated by means of grease sealed in the bearings at the factory, or +it may use greaseless bearings, and does not need to be oiled or greased +periodically. Indicate on your chart all motors which need periodic care +and see that it is given according to schedule. + +Wipe away any excess oil or grease. Be sure oil holes are capped or +covered. + +_Step 4._ Reconnect motor and run for a moment. + +_Step 5._ Record on the chart the date you serviced the motor and what +was done. + + +What Did You Learn? + +How many motors are there in your home? ______ On the farm? ______ + +How many motors need regular oiling or grease? ______ + +How many are less than one-horsepower? ______ + +SAE Oil ______ is used to oil motors up to 1/2 horsepower. How much +oil?______ + +SAE Oil______ is used for larger motors. + + +Demonstrations You Can Give + +1. Show how to clean a small motor. + +2. Explain proper lubrication of motors. + +3. Using the chart prepared in this work sheet, give a talk about the +motors that work for you-the job each one does, which ones need oil or +grease, which need no attention, and why, etc. + +4. Use a homemade toy motor to explain "what makes motors run." + +5. Show proper way to replace worn cord on a small motor. + + +For Further Information + +Ask your county Extension agent or 4-H leader for more literature on +motors. They can help you obtain a film or a speaker such as a power +supplier, a local electric dealer, or electrical contractor to discuss +motors. + +Also visit your public library and see a science teacher for more +information on motors. + + +ELECTRIC MOTORS SERVICE CHART Sample + +Use a table like the following to list the motors around your farm and +home. + + ---------------------------------------------------------------------- + Motor | Location |H.P.|Volt |Amp |Service |Date Serviced and + Use | | | | |Needed |what was done + ---------------------------------------------------------------------- + Food | Kitchen |1/6 |120 |4.4 |Clean & Oil; |9/1-Cleaned + Mixer | | | | |cord needs |w/cloth. + Repair | | | | |repair |Oiled w/#10 Oil; + | | | | | |repaired cord + ---------------------------------------------------------------------- + Tool | Farm |1/4 |120 |5.8 |Clear, oiling; |10/6-Cleaned + Grinder | Shop | | | |Have switch |w/vacuum Oiled #10 + | | | | |Have switch |oil. 10/20-Had + | | | | |repaired |switch repaired + ---------------------------------------------------------------------- + Pump |Pump |1/3 |120 |7.2 |Oiling, |9/26-Cleaned + |house | | | |cleaning |w/tire pump; + | | | | | |oiled w/10 oil + ---------------------------------------------------------------------- + + + + +LESSON NO. B-7 + +Credit Points 4 + +READING THE ELECTRIC METER + + +There is no question but what electricity is one of the lowest cost +services in the home and on the farm. A few pennies worth of electricity +will provide the power to run machines that take the place of a man or +of several men working all day. However, we all like to know what things +cost. + +Sometime you may have to decide between different methods--man, horse, +gasoline engine or electric motor power. Then you'll want to know how to +figure the cost of electricity, as well as the cost of the original +equipment. First of all, you should know how to read an electric meter. + + +Reading a Meter + +Electric meters read in kilowatt hours, just as a water meter reads in +gallons and a gas meter in cubic feet. A kilowatt hour is the electrical +energy consumed by 1000 watts of electricity used for one hour. Ten +100-watt light bulbs burning for one hour would use one +kilowatt-hour--one kwh. + +[Illustration: Figure 1. Some meters give the reading directly, like the +mileage total on a speedometer.] + +Some meters are read directly, as shown in Figure 1. The more common +type has four dials which are read from right to left--just the opposite +from the way things are usually read. The hand on the extreme right +turns clockwise, the next hand turns counter-clockwise, the next +clockwise; the last hand on the left turns counter-clockwise. + +The first dial on the right can register up to 10 kilowatt-hours; the +second up to 100 kwh; the third, to 1000 kwh; the fourth, to 10,000 kwh. +After that, the meter starts over again. To take a reading you must read +all four dials of the meter, from right to left. + +[Illustration: Figure 2. Meter dials are read from right to left.] + +To read each dial, you use the number last passed by the dial hand. This +may not be nearest the hand. For instance, if the pointer has passed 6 +and is almost on 7, you read it as 6. Write down the figures in the same +order you read the dial, from right to left. Practice reading the meters +shown in Figure 3 on the following page. + + +What's Your Electric Bill? + +Meters aren't set back each month when the meter reader comes around. +The difference in the readings from one month to the next shows how +many kilowatt-hours have been used. If you know your electric rates, you +can figure your bill by yourself. Your power supplier will furnish you +with a rate schedule on request. + +[Illustration: Figure 3. See if you can read the above correctly. The +answers are shown in a box on the next page.] + +It will be interesting to you to find out how much it costs to operate +the various electric appliances in your home. A sample rate schedule is +shown in Figure 4. + +[Illustration: Figure 4. Sample rate schedule. Note that as the use of +electricity increases, the average cost per kwh is reduced.] + + +Estimating Operating Costs + +To find the cost of operating any single appliance, three steps are +necessary: + +1. Learn the wattage of the appliance. + +2. Estimate how many hours the appliance is used. + +3. Find its operating cost. + + +_To Find Wattage:_ + +Watts, you know, are the measure of electrical power. They are the +product of voltage (pressure) times amperes (rate of flow). Volts times +Amps equals Watts. The nameplate on the appliance will give the voltage +required for proper operation as well as either amperage or watts. If it +gives wattage, you have the information you want. Otherwise you must +multiply volts times amps to get the wattage. When voltage is given as +110-120, use 120 as your voltage. 120 volts is nominal today. + + +_How Much Will You Use?_ + +Now that you know the wattage of the appliance, multiply this figure by +number of hours the equipment operates in one day. Divide this by 1000 +to get the kwh. Now multiply the result by the number of days the +appliance is used each month. This tells you the number of kwh used by +the appliance during the month. + + + |---------------------------------------------| + | | + |Example No. 1 | + |_Yard Light:_ 300-watt lamp | + | | + |Amount of use: 3 hours per night. | + | | + |Multiply lamp wattage times hours of use | + |per night to get watt-hours per night. | + | | + |300 times 3 = 900 watt-hours per night. | + | | + |Divide watt-hours by 1000 to get kwh per | + |night. | + | | + |900 divided by 1000 = .9 kwh per night. | + | | + |Multiply kwh per night times 30 to get kwh | + |per month. | + | | + |.9 times 30 = 27 kwh per month. | + | | + |If the yard light is used 3 hours per night, | + |it consumes 27 kwh per month. | + |---------------------------------------------| + + +Example No. 2 + +_Coffee Maker_: 120 volts, 550 watts (from nameplate) + +Amount of use: 1/2 hour per day. + +Multiply wattage of coffee maker times hours of use per day to get +watt-hours per day. + +550 times 1/2 hour = 275 watt-hours per day. + +Divide watt-hours by 1000 to get kwh per day. + +275 divided by 1000 = .275 kwh per day. + +Multiply kwh per day times 30 to get kwh per month. + +.275 times 30 = 7.250 kwh per month. + +If the coffee maker is used l/2 hour daily, it consumes 7.25 kwh per +month. + + +_Calculate Operating Cost Per Month_ + +Now that you know the number of kilowatt hours an appliance uses, go to +your rate schedule and your electric bill to see what the average kwh +costs. Find the average cost of 1 kwh by dividing the amount of your +bill by the total number of kwh used in a month. + +_Example_: 410 kwh used. $14.35 total monthly bill + +Average cost per kwh equals $14.35 divided by 410 kwh-3-1/2 cents per +kwh. + +Therefore, the cost of operating the coffee maker for a month would be +3-1/2 cents times 7.25 kwh--25.4 or 25 cents. Cost of operating the yard +light would have been 94.5 or 95 cents a month. + + +(a) 6357 (b) 1963 (c) 8996 + +Correct answers to the meter readings shown on the preceding page. + + +Adding Low Cost Helpers + +You can see, by looking at your rate schedule, that the average cost per +kwh gets lower as you use more electricity. To find the cost of +operating additional electrical equipment, the cost per kilowatt hour is +found from the last "step" in the bill--the lowest cost per kwh of the +electricity you're now using. Sometimes power suppliers give special +rates for such equipment as electric water heaters. + + +WHAT TO DO: Find the Cost of Operating Electrical Equipment + +Make and fill in the blanks of a chart showing the electrical equipment +you have and the operating costs per month. + +Make a chart for the home (refer to chart one). Show the probable +operating cost of equipment you might add to what you now have. + + +Demonstrations You Can Give + +Show how to read a meter, making one with plywood or cardboard. Dials +can be painted on the main board. Arrows can be attached so they will +revolve to give different readings. + +Show how to find the wattage of various types of equipment. + +Show how to figure the cost of the average kwh in a home. + + +For Further Information + +Your leader can get additional material for you or you may want to have +someone from your power supplier talk to your club, telling about +meters, how they work and how they are regularly checked for accuracy. + +Chart One-THE HOME + + + Column No. 1. 2. 3. 4. + + Item Wattage Hours KWH per Cost per + Rating Used Month Month + per (col. 1x2)/ (Col. 3 x av. Remarks + Month 1000 kwh cost) + + Electric Iron 1100 30 33 .80 + Stove 880 60 52.8 1.21 (Special + rate) + + + +LESSON NO. B-8 +Credit Points 3 + +IRONING IS FUN WITH THE MODERN HAND IRON + + +When you are getting ready to go to school or to a party, it probably +gives you a good feeling to put on a clean, freshly-ironed skirt, blouse +or dress. But did you ever think about the electric iron that helps so +much to give you that well-dressed feeling? When you were younger, you +may have had a play iron and pretended to iron your doll's dresses. Now +you are old enough to learn about real irons--the different kinds of +irons, how the iron heats, the kind of cord needed, the type of outlet +necessary, how to use safety rules when you iron, and even how to help +with the ironing. + + +Important Things to Know + +There are many different irons, but the two kinds most important for you +to know about now are the regular dry iron and the combination +steam-and-dry iron. + +[Illustration: The thermostat keeps the iron at an even temperature.] + +It isn't weight alone that makes an iron do its job, but the heat of the +iron. The heat is given off in the sole plate. The automatic iron has +what is called a _thermostatic_ control which holds the temperature of the +iron at the heat you want. Some clothes need to be ironed with a very +hot iron, while others need only to be pressed lightly with a cool iron. +The thermostat keeps the iron at an even temperature after you set it +for the heat you want. The thermostat is the heart of the iron. + +Take a look at the iron used in your home. It isn't heavy to lift, and +has a handle that fits your hand easily. It looks graceful and has a +smooth bottom, called the sole plate. And it may have a narrow, pointed +tip which is helpful in ironing pleats, corners and gathers. + +[Illustration: Your iron has a smooth bottom called the sole plate.] + + +The Iron and Safety + +If you are going to learn to do some ironing yourself, the most +important thing for you to remember is SAFETY. You should read all about +the iron first in the instructions which came with it. + +Never use an iron carelessly. Remember the safety rules: + +1. An iron should never be left even for a few minutes without being +disconnected. Turn off by removing the plug from the outlet, or by +turning the control lever to "off." + +[Illustration: Take hold of the plug--not the cord--when you disconnect +it from the outlet.] + +2. Let the iron cool before putting it away. + +3. Wrap the cord carefully around the iron after it is cold. + +4. Always stand the iron where it will not fall off on a child or pet or +your own toes. + +WHAT TO DO: Learn About Your Iron + +Materials Needed: An automatic iron, some old play clothes, towels, +napkins or handkerchiefs, and an ironing board. + + +Steps to Take: + +1. Watch an experienced person iron. + +2. Ask questions about what clothes need to be sprinkled. + +3. Study the thermostat settings on the dial or indicator. + +[Illustration: Most irons have a dial to set for the proper heat for +different fabrics.] + +4. Ask about the kind of fabric each piece of clothing is--cotton, +linen, silk, nylon, etc.--and why the iron should be at high heat for +some, cooler for others. + +5. Set the thermostat for the amount of heat needed, and with an older +person watching you, iron some handkerchiefs, napkins, bath towels, and +a pair of play shorts or blue jeans. + +6. During a month iron some of these articles for your family, keeping a +record of how many you do and what they were. + +7. Take care of your iron. Be responsible for storing it. + + +--------+-----------------+-------------------+---------------------+ + | | No. | | Store Iron Properly | + | Date | Articles Ironed | Type of Article | (check) | + +--------+-----------------+-------------------+---------------------+ + | | | | | + +--------+-----------------+-------------------+---------------------+ + | | | | | + +--------+-----------------+-------------------+---------------------+ + + +IRONING IS FUN + +1. I (use) (do not use) an adjustable ironing Board at home. If I do, I +adjust it to the height that just clears my knees easily as I sit in a +comfortable chair. Yes No + +2. There are three kinds of irons usually used--dry iron, steam iron or +a combination steam or dry iron. I use a ---- iron. + +3. I (have) (do not have) the instruction book. (If you do, read about +the iron.) I know the iron's parts by their correct names. They are----. + +4. I disconnect the iron if I leave it even for only a minute. This is a +safety measure as fires have been known to start from irons left +connected. Yes No + +5. I take hold of the plug--not the cord--when disconnecting the iron. +Yes No + +6. I wait until the iron is cold before wrapping the cord around the +handle and storing the iron because----. + +7. Most irons have a thermostatic control. The iron I am using has +settings for----. + +8. The purpose of the thermostat is----. + +9. These fabrics need high temperature.---- + +These fabrics need medium temperature.---- + +These fabrics need low temperature.---- + +10. These fabrics need sprinkling.---- + +11. The heat and smoothness of the sole plate smoothes the wrinkles. +Pushing down on the handle or moving the iron rapidly only makes ironing +hard work. I will iron slowly and steadily arranging and moving the +garment with the left hand while guiding the iron with the right hand. +(Or the other way for the left handed.) Yes No + +12. I have watched an experienced person iron. Yes No + +13. I have practiced on handkerchiefs, napkins and pillow cases. + +14. Here is my record of ironing for one month. + + + Month ---- + Your Name ---- + + Date I have ironed: + ---------+------------------------------------------------ + | + | + + + +Demonstrations You Can Give + +1. Show a dry iron and a steam-and-dry iron. Tell the difference between +them and when each is to be used. + +2. Display garments that look nice because they have been ironed +properly, and those that have been ironed improperly. Explain about the +heat, thermostat, type of iron and why results differ. + + +For More Information + +At a club meeting ask a parent to give a demonstration of ironing +different articles. Some power suppliers or dealers have people who will +demonstrate the proper way to iron, and how to care for irons. + + + + + +LESSON NO. B-9 +Credit Points 2 + +LET'S BE FRIENDS WITH ELECTRICITY + +Plan a Hazard Hunt + + +Electricity can be your important lifelong friend and helper, so you +will want to know all you can about it and how to treat it properly. +However, careless and improper use of electricity can do a lot of harm. +Used properly, and treated with respect, electricity can do wonderful +things to help you every day in many ways. + +For safe and proper use of electricity, all wiring, fittings, +insulation, cords and plugs must be in good condition. You can be a +detective and track down defects in any such type of electrical +equipment that you may be using in your home or on your farm. + +When you find anything that is wrong, and know where it is, and know +what to do about it, you can very likely correct the condition yourself, +such as replacing a worn extension cord with a new one. If you find +defects in permanent wiring, or some places where wires are bare or +terminals are needed, you should tell your parents about them. + +SAFETY FIRST, remember, should always be on your mind when working with +anything electrical. + + +WHAT TO DO: + + +_1. Have A Hazard Hunt_ + +Go on a Hazard Hunt to see how many electrical hazards you can find. +Look for defects such as broken insulation, worn cords, splices that are +not properly soldered and taped, loose connections, or switches that +aren't working properly. + +There are many ways to have a Hazard Hunt. Choose the method that will +be the most fun. Use the Hazard Hunt Guide in this outline to check your +home, and other buildings. Maybe you'll want to have a friend help check +your home, then you help him check his. Or, why not give each member of +your family a Hazard Hunt Guide and have a contest? Parents may want to +team up against you and other younger members of your family to see +which team can find the most electrical hazards in some set time--say 30 +minutes. + +Have a Hazard Hunt Committee in your club check all member's homes and +buildings and report its findings at the next club meeting. + +_To Make It More Fun_ + +1. Put a hazard tag, like the one shown, (Figure 1) by each hazard that +is found. Leave it until the hazard is corrected. Have another contest +to see which member of the family corrects the most hazards. + +[Illustration: Figure 1] + +2. Report on your Hazard Hunt at the next club meeting. Tell about the +Hazards found, and what you have done or plan to do about them. + +3. Suggest that the entire club have an Electric Hazard Hunt at your +club meeting places or any community building. This could be part of one +meeting. + +4. Have a contest between two teams in the club to see which team can +get the most homes in your community checked by the Hazard Hunt Guide. +Losers could give a party for the winners. + + +_2. Get Others Interested_ + +Promote a community Electric Hazard Hunt. Enlist the support of power +suppliers, electric supply and equipment dealers, schools, newspapers, +radio and television stations. + + +_What To Look For_ + +Make a complete tour of your home and other buildings and see how many +hazards you can locate. When you find a hazard, put a tag near it to +mark it. + + +SAFETY TIPS + +Put hazard tags _near_ the hazard but _not_ directly on broken or frayed +wires, insulators, fittings, or other wiring equipment. Do not touch +them either. Badly-frayed wires should be disconnected immediately from +the power supply. In this way, you will not expose yourself to shock by +accidentally touching an exposed live wire that may be carrying current. + + +4-H Electric Hazard Hunt Guide + +_Wiring and Protective Devices_ + +1. Cable or conduit splices not in boxes---- + +2. Cable or conduit not securely clamped in boxes---- + +3. Conduit or armored cable not properly grounded---- + +4. Cracked or broken insulators (Figure 2)---- + +5. Wire not completely covered with insulation---- + +6. Worn insulation on wire---- + +[Illustration: Figure 2] + +7. Old unused wiring not yet removed---- + +8. Outlets, junction and switch boxes not securely fastened and covers +not in place---- + +9. Switches not working properly (sparks fly as switch is flipped) +(Figure 3)---- + +10. Fuses not of proper ampere rating for circuit---- + +11. Extension cord used in place of permanent wiring---- + +12. Pull chain socket without an insulating link in the chain---- + +13. Pull chain socket near plumbing fixtures or where hands may be wet +or one may stand in water---- + +[Illustration: Figure 3] + +14. No moisture-proof cords for outside weather conditions or heavy +rubber cords for motors and motor driven appliances + + +_Lighting_ + +1. Fixtures in farm buildings installed so that they might be easily +damaged + +2. Lights in haymows and other dusty locations not protected by +dustproof globes + +3. Outside sockets not waterproof + +4. Heat lamps not properly supported by non-current carrying wire, +chains, or brackets (Figure 4) + +5. Light bulbs not frosted, shaded, or placed so that light is diffused +to prevent glare + +[Illustration: Figure 4] + + +_Auxiliary Wiring_ + +1. Outlets overloaded--in other words, "octopus wiring" + +2. Extension cords placed under rugs + +3. Extension cords run through doorways (Figure 5) + +[Illustration: Figure 5] + +4. Extension cords or lamp cords should use underwriters' knot (Figure +6) + +[Illustration: Figure 6] + +5. Plug connections fuzzy (Figure 7) + +[Illustration: Figure 7] + +6. Extension cords run over heaters or radiators + +7. Extension cords, or appliance or lamp cords, worn or frayed + +8. Heating appliances without regular asbestos covered wire + +9. Open sockets or outlets where a baby or small child might stick a +finger or metal toy + +10. Broken plugs (Figure 8)---- + +11. Loose prongs on appliance or lamps plugs---- + +[Illustration: Figure 8] + + +How Many Hazards Did You Find? + +Make a chart listing the hazards, their locations and what you did about +them. Make your own chart and list what you find. + +Demonstrations You Can Give + +Show and tell others how to have a Hazard Hunt. + +For Further Information + +Check with your leader, then ask your power supplier or a local +electrician to tell you about safe electrical wiring, connections and +fixtures. + + +-------------------------+-------------+------------------------+ + |Hazard | Location |What I Did | + +-------------------------+-------------+------------------------+ + |_Loose prong on lamp plug|Living Room |Replaced with new plug_ | + +-------------------------+-------------+------------------------+ + |_Cracked insultor on |Back of house|Notified power _ | + |_service wire in house | |supplier_ | + +-------------------------+-------------+------------------------+ + |_Conduit not securely |Basement by |Notified parents_ | + |_clamped to box |fuse box_ | | + +-------------------------+-------------+------------------------+ + |_Extension cord, old and |Basement, by |Replaced with new_ | + |_worn |washing |rubber-covered one and_ | + | |_machine |protected it from _ | + | | |_water_ | + +-------------------------+-------------+------------------------+ + + + + +LESSON NO. B-10 +Credit Points 3 + +HOW ELECTRIC BELLS WORK--FOR YOU + + +When was the last time you wanted to get a simple message like "You're +wanted on the telephone," "There's someone here to see you," or "There's +a car in the driveway," to someone around your place? Did you have to +walk or run some distance and perhaps shout, too, to be heard by the +other person? Perhaps you had to stop some other work, or interrupt your +favorite kind of fun, to do this bit of messenger work. + +If the nature of the message is like one of those mentioned, and the +number of people in hearing is not too great, then perhaps you can use +bells or buzzers or both to do some of your messenger work for you. Even +though a bell or a buzzer can't talk, it can convey a message. + + +What to Do + +1. Learn how bells and buzzers work, and learn about the many different +kinds. + +2. Plan and install a bell system for your home or farm. + +Bells and Buzzers Can Tell a Lot + +Electric bells and buzzers use the same basic principle as the telegraph +system, invented by Samuel Morse in 1840. Although not as important +today as it was before radio, telephone, and teletype became common, the +telegraph is still in use. + +Bells and buzzers, however, are very common and have many uses. They are +most often seen in the form of doorbells, and rare is the new home that +does not have one or more. Service stations have bell systems to let the +operator know that a car is waiting at the gas pumps. A clock signal +reminds the homemaker when the cooking time is completed. Children are +called to and released from school classes by means of bells and +buzzers. + +Also, various alarms employing bells and buzzers warn us when it's time +to get up, or even that the place is on fire, or that a burglar is +trying to break in! + +Let's find out how bells and buzzers work, what different kinds there +are, the different ways you can control them, and how you can put them +to work for you. + +You'll find that buzzers and bells can help you with your 4-H projects, +and with the proper controls, can be your eyes and voice in a dozen +places at once. + +Why They Buzz or Ring--Electromagnetism + +If we were to look at an electric bell with the cover off, we'd find +that it would be very much like Figure 1. + +A push on the button, which is just a switch that is normally held +"open" or off by means of a spring, sends the current from the battery +or transformer through the circuit. + +[Illustration: Figure 1] + +You will see that the current passes first through two small coils of +wire, and each coil has at its center a piece of soft iron called the +core. When the current is on, the core becomes magnetized and attracts +another piece of iron called the armature with its clapper attached. + +This action rings the bell, but it also breaks the current by pulling +the spring away from the screw on its return to the power supply. + +With the power off, the electromagnet lets the spring return the +armature to its normal position, contact is made again, and the cycle +starts all over again--just as long as you continue to push on the +button. + +Buzzers work exactly the same way, except that they do not have a bell +and depend instead on the vibration of the armature for a noise that's +not as loud or as musical. + +Gongs or chimes, that strike only once when the button is pushed, are +made by connecting the armature with the screw by means of a flexible +wire. + + +A Special Kind of Electricity + +Most buzzers and bells work on a much lower voltage than you normally +find in the wires in your house. Some are made to work at 6 volts, +others at 10 volts, and still others at slightly higher voltages. + +You can get these low voltages by using one or more batteries, or by +using a transformer connected to your house current. Most bells and +buzzers are now powered through transformers. + + +How to Control Them + +The push button is the most common means of control. You can use one +button to control several bells, or several buttons to control one bell, +or have several buttons control several bells. Because low voltage is +used, adding extra buttons is simple, inexpensive, and safe. + +Buzzers and bells can also be controlled by: _clocks_, as in the +interval timer on an electric range or in a school class bell system; +_temperature detectors_, as in a fire alarm or freezer alarm; _door and +window trips_, as in a one-man repair shop or in a burglar alarm; and +_treadles_, as in the driveway of a service station. + +[Illustration: Figure 2] + + +Pick the Right Bell or Buzzer + +Some of the many different types of bells, and various ways of +controlling them are suggested in the table below. Just remember that no +matter what the job or conditions, you can probably find a bell or +buzzer and controls that suit your need. + + +SOME TYPICAL JOBS FOR BELLS & BUZZERS + + -------------------------------------------------------------------- + Number and + Type of location Number and + bell or of bells Type of location + Job buzzer and buzzers control of controls + --------------------------------------------------------------------- + Summon others In the house-- Enough to Push- One at the + to the small to cover all buttons telephone + telephone medium buzzers usual work and each + In locations extension + outbuildings-- phone + medium to + large bells + Outdoors-- + large + weatherproof + bell + All transformer- + powered + --------------------------------------------------------------------- + Notify club Medium to large One may be Hose One--in + member that bell-- enough--if diaphragm the + car is at his transformer- mounted on driveway + produce stand powered the back of ----------------------- + the stand (Complete driveway + including control, + are available, + ready to plug in.) + -------------------------------------------------------------------- + Warn of power Battery-powered One near Relay, One, at + failure to buzzer, medium the held open main + incubator or size poultryman's as long as switch of + brooder bedroom power is on, hatchery + closed by or + spring if brooder + interruption house + occurs + -------------------------------------------------------------------- + Warn of Battery-powered One, in or Temperature One, with + dangerously buzzer, medium near the detector bulb + warm size kitchen (sensitive inside + temperature thermostat) freezer + in freezer + --------------------------------------------------------------------- + + +How to Plan Your System + +To save your time and steps when the telephone rings for someone else in +your family who is some distance away, you can install a simple bell or +buzzer system to summon that person. + +First, you must plan what you are going to do. On a large sheet of +paper, draw to scale (roughly) a plan of your house and grounds, +including those places where phones are located. It will help if you +rule off your paper in 1/8" or 1/4" squares and let each square equal +one foot. Show the location of poles supporting your wiring. + +Next, pick out those areas where you or others would likely be when +someone else would answer the phone and want to call you to it. + +After you have thought about this, and talked it over with members of +your family, show locations on your plan where you think you would like +to have buzzers or bells, and show a button beside each telephone. +(Generally, you should have a bell or buzzer near each phone, also.) + +Figure 3 shows diagrams of various types of systems, and will help you +determine the number of wires you will have to install to connect the +buttons and bells that you have planned. + +Inside, you will connect your transformer and the various buttons and +bells with ordinary indoor bell wire. Outdoors, however, you should use +weatherproof 2-wire or 3-wire telephone twist. + +Show on your plan the distances that must be traversed by each type of +wire, and show the number of conductors in each. Don't overlook the +vertical distances (one floor to another). + +[Illustration: Figure 3] + + +Materials You'll Need + +Because no two situations are just alike, it will be necessary for you +to make your own list of materials. + +As a guide, however, here is a list of typical materials, with the +quantities left blank, for you to fill in as your own requirements and +measurements dictate. + + 10-volt transformer + --- Door buzzers + --- Doorbells + --- Weatherproof outdoor type bells + --- ft. indoor bell wire + --- ft. 2-wire weatherproof telephone twist + --- ft. 3-wire weatherproof telephone twist + --- lbs. staples (insulated) + --- entrance insulators (for attaching + weatherproof to buildings and poles) + +Because your transformer must be wired into your regular house current, +you should have some help on this from an electrician or other qualified +person. Also, you should get that person to review your plans and +materials list before you place an order. + + +Install According to Your Plan + +With the aid of an electrician or other qualified person, install your +transformer, and test it. + +You may then go ahead and complete your signal system, checking +carefully with your plan, and making sure that your installations are +both electrically and mechanically secure. + +Test your system in all possible ways that it might be used. + + +Demonstrations You Can Give + +Build a demonstration board incorporating a farm or home layout, with +pushbuttons or other controls and bells and buzzers appropriately +located. Show and tell how the system would save time and energy. + +Show and tell how some of these work, and their value: power-off alarm, +freezer alarm, fire alarm, driveway alarm. + + +For More Information + +Ask your power supplier or your nearest electrical supply house for +catalogs or literature on various types of signal systems, or ask a +dealer to show you equipment he has in stock. + + + + +LESSON NO. B-11 + +Credit Points 2 + +FIRST AID FOR ELECTRICAL INJURIES + + +What would you do if you saw someone who had been hurt by electricity? + +Did you know that you could save his life, if you had taken the time to +learn and practice a few simple rules of electrical first aid? + +First aid training equips you to know what to do and what not to do for +the injured until medical help can be obtained. While the main benefits +are for you and your family, no one can call himself a good citizen if +he fails to help a stranger who has been hurt. + +The information given here is only for electrical injuries. Perhaps what +you learn will inspire you to take a complete course in first aid. + + +What to Do + +Learn how to prevent electrical accidents, and what to do if an +electrical accident occurs. + +1. Make an electrical hazard hunt in your home or on your farm. Point +out to your parents everything that should be repaired or replaced for +safety's sake. + +2. Read the first aid suggestions that follow. Learn them. + +3. Get to know the six steps that are outlined for mouth-to-mouth rescue +breathing. Practice them on your brother, sister, or parents. Teach the +entire family how to do it. + + +Electricity Can Kill + +In this day of hundreds of uses of electricity, you should know about +electrical dangers. Electrocution can occur from either low voltage +(household type) or high voltage currents. Sometimes household voltages +are more hazardous because people underestimate the dangers involved. + +A fraction of an ampere passing through your heart muscles can be fatal. +Your body offers some resistance to the flow of electricity to ground. +If you are standing on wet ground or in water, or if your skin is damp, +this resistance is greatly reduced. + +Wire cables within walls and cords on appliances are all insulated with +a shock proof covering. Continued use, age, or damage may expose a bare +wire and create a hazard. The point of exposure need be only a fraction +of an inch. Cords are often used and abused. Exposed wires and signs of +wear are danger signals. + +Always be wary of overhead wires. People have been injured or killed +when kite strings, model plane control lines, irrigation pipe, and water +well equipment have come in contact with the power supplier's or their +own overhead wiring. + + +Prevent Accidents + +Underwriters' Laboratories (UL) have taken steps to see that minimum +safety standards are met in the manufacture of electrical equipment. +Look for the UL label when you buy cords or appliances. Never place +cords under carpets or furniture, or drape them over a nail. Replace or +repair worn cords without delay. + +Be especially careful when operating electric devices in the bathroom. +Keep in mind the dangers of a wet floor, grounded metal pipes, and wet +skin. Turning on an AC radio while you are taking a bath is asking for +real trouble. + +There may be shorts in electric devices. Keep your hands dry when using +them, and do not touch them along with grounded metal objects. If you +ever get a slight shock, sound the danger signal and do something about +it. + + +Think, Then Act + +Your first thought in rescuing a victim from an electrical accident +should be your own safety. Speed is also important, because a few +seconds or minutes may save a life. + +The first question you should ask yourself is "Can I quickly turn off +the power?" This would be easier to do in the home than outside. In the +case of a victim trapped in a bathtub from a radio accidentally knocked +into the water, it might mean simply removing the plug from the wall +outlet. If a victim is found grasping shorted, permanently installed +equipment and cannot let go, the main switch might be used for quick +release of the current. + +Outdoors, especially with high tension wires, your danger in rescue is +much greater. To handle the victim, touch him only with a long dry +stick, dry rope, or a long length of dry cloth. Be sure your hands are +dry and that you are standing on a dry board. A broom might be a good +lever to pry a victim from a high tension wire but never use a green +stick containing sap. + + + +First Aid + +Once the rescue has been made and the victim is free of further danger, +check to see if breathing has stopped. If so, start artificial +respiration _immediately_ and send someone for a doctor. + +Artificial respiration must be started as soon as possible after normal +breathing ceases. _Most persons will die within 6 minutes or less if +breathing stops completely unless they are given artificial +respiration._ Precious minutes may have passed before you get to the +victim. Since the victim may be within seconds of death by the time you +are able to touch his body, you should seek to obtain an air flow to and +from the lungs _immediately_. + +The victim may seem stiff as an effect of the current, so don't give up +easily. Continue the procedure for several hours. If transportation is +necessary, remember that there may be internal injury, fractures, or +severe burns. + + +Mouth-To-Mouth Rescue Breathing + +There are various effective ways to give artificial respiration, each +with its advantages and disadvantages. The mouth-to-mouth method is +recommended as a good one to master. It can be used on victims of +drowning, suffocation, and asphyxiation, too. People have been known to +save lives with less exposure to the correct procedure than you are +getting by reading this. So, pay attention and remember what you read. + +Step 1. Turn the victim on his back. Wipe out victim's mouth quickly. +Turn his head to the side. Use your fingers to get rid of mucus, food, +sand, and other matter. + +[Illustration: Head Position] + +Step 2. Straighten victim's head and tilt back so that chin points up. +Push or pull his jaw up into jutting out position to keep his tongue +from blocking air passage. This position is essential for keeping the +air passage open throughout the procedure. + +[Illustration: Push Jaw Up] + +[Illustration: Pinch Nostrils] + +Step 3. Take a deep breath, place your mouth tightly over victim's +mouth, and pinch nostrils closed to prevent air leakage. For a baby, +cover both nose and mouth tightly with your mouth. (Breathing through +handkerchief or cloth placed over victim's mouth or nose will not +greatly affect the exchange of air.) + +[Illustration: Breathe] + +Step 4. Breathe into victim's mouth or nose until you see his chest +rise. (Air may be blown through victim's teeth, even though they may be +clenched.) + +Step 5. Remove your mouth and listen for the sound of returning air. If +there is no air exchange, recheck jaw and head position. If you still do +not get air exchange, turn victim on side and slap him on back between +shoulder blades to dislodge matter that may be in throat. Again, wipe +his mouth to remove foreign matter. + +Step 6. Repeat breathing, removing mouth each time to allow air to +escape. For an adult, breathe about 12 times per minute. For a child, +take relatively shallow breaths, about 20 per minute. Continue until +victim breathes for himself. + + +What Did You Learn? True or False + +1. A broken arm should be splinted before artificial respiration is +applied to a victim who is not breathing. + +2. A person who has been severely shocked with an electric current +should lie down. + +3. A doctor should be called even though you successfully have revived a +victim's breathing. + +4. A fraction of an ampere through the human heart muscles can be fatal. + +5. A copper wire would provide a better path than your body for stray +currents, therefore all appliances should be grounded if possible. + +6. Outside wires are never a hazard because they are covered with +insulation when they are installed. + +7. Cords need not be repaired until you can see bare wires. + +8. Tuning in an AC radio while you are bathing is always dangerous, even +though your hands are dry. + +9. In an emergency, a broom is an acceptable tool for prying a victim +off a high tension wire. + +10. In mouth-to-mouth breathing, an adult's lungs should be filled 12 +times per minute and a child's 20. + + +Demonstrations You Can Give + +Show how to deal with an electrical first aid "problem" given to you by +your leader. + + +For More Information + +Ask your leader to have a first aid expert put on a demonstration. (Many +industrial plants and power suppliers have such people.) + + + + +LESSON NO. B-12 + +Credit Points 3 + +HOW ELECTRICITY HEATS + + +In ancient times, people thought that heat was a material just as air +is. They called it "caloric". When something got warm, they said, +caloric flowed into it. When something cooled off, caloric flowed out of +it. It did not bother them that they could not see caloric. They could +not see air either! + +Now we know that heat is not a material. It does not take up space. It +does not weigh anything. Instead, it is a form of energy. And when we +say that heat is a form of energy, we mean that it can be used to do +work. + + +What to Do + +1. Make a simple resistance heater. + +2. Make some popcorn by: + +(a) conduction (b) convection (c) radiation + + +"Resistance" Makes Heat + +There are at least four ways that electricity can make heat. The one +that we'll cover here is _resistance_ heating. (The others are: +_dielectric_ heating, where the lines of force of an electrostatic field +pass through a non-conductive material and heat it; the _heat pump_, +which is a refrigerator in reverse; and _electronic_ heating, which uses +high frequency waves similar to radio waves to create high speed +movement of the molecules or tiny particles which rub together to make +heat.) + +_Resistance_ heating occurs because every conductor of electricity +opposes the flow of current through it. Some conductors resist more than +others. When they do, a certain amount of warming takes place. The more +resistance that is offered, the more heating there is. + +Some materials, like silver, copper, and aluminum, offer little +resistance. We say they are good conductors. + +Other materials, like iron, offer more resistance. They are still +conductors, but not as good as the others mentioned. + +The _size_ of the conductor, and its _length_ are the other two things +that affect its resistance. The _smaller_ it is, the greater its +resistance. Also, the _longer_ it is, the greater its resistance. +Therefore, when we only want to _move_ electricity from place to place, +we want relatively large, "good" conductors. Here, we do not want to +make heat. In fact, we want to avoid it, because too much heat in the +wrong place can cause a fire. + +But when we want heat, we choose relatively small, "poor" conductors, +and the more heat we want, the longer they must be. If you will think of +the filament inside a lamp bulb; you may recall that it is a very fine +wire, coiled so as to get a maximum length, and made of tungsten which +has a high resistance. + +Because of all these factors, this filament glows at a white heat, and +is a source of both light and heat. + + +Make a Simple Resistance Heater + +_Materials you will need_: + + 1 dry cell battery + 1 foot iron picture wire + Pliers + +Use a short strand of iron picture wire and hook the ends to the +terminals of a dry cell battery. Use pliers so that you do not burn your +fingers. Disconnect the wires as soon as they become hot. Tell why the +wires heat. + + +Conduction is "Touching" Heat + +Conduction occurs when you set a pan containing food right on a heating +element. An egg cooking in a hot frying pan is a good example of +conduction at work. This method is the most efficient single way of +using electric heat for cooking. + + +Convection Depends on Air + +Convection warms food in pans that are not actually touching the heating +element. It uses the hot air around the element to carry heat to the +pan. + +Your oven in your range works by convection. Most houses are warmed in +winter in the same way. The heat produced in a furnace warms the air as +it circulates through. This air in turn keeps your body warm. + + +Radiation is Like the Sun + +Radiation heating is more difficult to explain. It results when heat or +energy waves strike an object and are converted into heat. The energy we +receive from the sun is a good example. When you are wearing dark +clothes on a chilly day, you may become uncomfortably hot. The sunshine +warms you even though the air around you has not been heated. Radiant +energy has a way of being absorbed by dark objects and reflected by +light colored or shiny surfaces. Did you ever notice how snow melts +faster on a black top road than it does on a concrete road? + +The electric heat lamp is one of the most familiar sources of radiant +heat. Other examples are panels and cables that are built into the walls +and ceilings of homes to provide heat. + + +Make Popcorn 3 Ways + +How do you make popcorn? Did you know that you can do this kind of a +heating job three different ways? + + +_Materials Needed_ + + Popcorn + Cooking oil or shortening + Salt and butter + 4-qt. saucepan, with cover. (A glass cover + is preferred.) + Potholder + Electric range + 2 250-watt heatlamps + 2 spring clamp type lampholders + Wire mesh corn popping basket or wire + mesh kitchen strainer (improvise a + screen wire cover) + +_First_, make popcorn the way you usually do. Set a front surface unit +control on the range at "medium high". Pour enough oil to very lightly +cover the bottom of the pan. When the pan is hot, pour in enough popcorn +to cover the bottom with one layer of kernels. Use the potholder in one +hand to hold the cover on, and with the other move the pan back and +forth across the unit. When the popping stops, remove from the heat. + +How did the heat get to the popcorn? + +_Second_, make popcorn in the oven. Add the oil to the pan, cover it and +put it in the oven. Turn the oven on, with the automatic control set at +400°. When the oven indicator light goes off, this means that the proper +temperature has been reached. With the potholder, remove the pan and add +one layer of popcorn kernels. Replace the pan in the oven. When the +popping stops (listen for it) remove the pan. + +What kind of heating took place here? + +_Third_, make popcorn with the heat lamps. Clamp the lampholders to the +back of a chair or other vertical support. They should be 6 to 8 inches +apart and pointed directly at each other. Put about 2 tablespoonfuls of +popcorn in the Wire basket or strainer. Do not add oil. Hold the basket +midway between the two lamps. When the popping stops, turn off the +lamps. + +What kind of heating was this? + +Now, butter and salt the popcorn you have made and share it with others. + + +What Did You Learn? + +1. How is heat transferred from one body to another? + +2. Could chicks or pigs receive warmth from a heat lamp without the air +in the pens becoming warm? Explain. + +3. How does a broiler unit in a range cook meat? + +4. How does an oven bake food? + +5. Tell why iron picture wire was used instead of copper wire for your +heating demonstration. + + + + +LESSON NO. B-13 + +Credit Points 2 + +MYSTERIOUS MAGNETISM + + +In ancient times, people found certain rocks that clung together in +bunches. These rocks were very mysterious. People didn't understand them +and many superstitions grew up about lodestones, as these rocks were +called. Lodestone (sometimes spelled loadstone) means leading stone. +People even told Columbus not to sail out of sight of land because a +giant lodestone was just over the horizon waiting to pull all the nails +out of his ships. + +The Chinese were the first to use magnets. They found that if you hung a +lodestone by a string, one end of the stone would always point in the +direction of the North Star. They had the first magnetic compasses. + +An artificial magnet can be made by stroking or gently rubbing a piece +of steel with a lodestone. This piece of steel then can be used to +magnetize another piece of steel. This can be continued on and on. +Lodestones are not always available but you can get the same results +with an electric current. So, magnetism and electricity are very closely +related. + + +What to Do + +Learn about magnetism by doing the experiments that follow. + +Seeing is believing! + + +Materials You Will Need + + + 2 dry cell batteries (#905) + A few feet of No. 18 bell wire + 3 steel knitting needles or similar hard steel + 2 ft. of light thread + Sheet of light cardboard or stiff paper + Permanent magnet (bar or horseshoe) + Compass + 1 or more large nails or spikes + Red and black china-marking pencils or crayons + + Iron filings + Wire cutters + Carpet tacks + + +(Iron filings usually can be found under the grinding wheel in a shop. +If you can't find any, rub some steel wool pads together to produce bits +of metal that will do.) + + +"See" a Magnetic Field + +Cover the permanent magnet with the cardboard or paper. Sprinkle iron +filings on the paper. Tap the paper and note the pattern formed. Strings +or lines of filings pass from one pole of the magnet to the other. The +area covered by the filings is the center of the magnetic field. To +remember this, you might compare the magnetic lines of force that +arrange the iron filings to the contour strips in a farmer's field. + +This magnetic field is one of the important things in our everyday life +with electricity. If it were not for the magnetic field, we would not +have electric motors. Telephones, radios, television, and many other +things we use every day also depend on this magnetic field. + +[Illustration: Figure 1] + + +Make an Electro-Magnet + +You can make magnetism work for you by winding several turns of +insulated wire around one or more large nails or spikes (soft iron). +Connect one end of the wire to the battery. Touch the other end of the +wire to the other terminal for a few seconds and see how many tacks you +can pick up. Repeat the experiment using as many turns as possible. How +many more tacks were you able to pick up? + +[Illustration: Figure 2] + +You have made what we call an electromagnet. When you disconnect the +wire, the nails fall off. This is one of the advantages of an +electromagnet. We can turn magnetism on and off as we wish. Picture a +crane operator throwing the switch and picking up scrap iron and steel. +Then he opens the switch to drop the scrap metals. + +Soft iron can be magnetized easily as you have just seen, but loses its +magnetism in a short time. Steel is harder to magnetize but holds its +magnetism almost indefinitely. + + +Make a Permanent Magnet + +Wrap the insulated bell wire around the steel knitting needle. The wire +should be wrapped the full length of the needle. One end of the wire is +connected to the battery. The other end of the wire is then touched for +just a few seconds to the other terminal. This should make the needle +into a permanent bar magnet. If you did not get results, try two +batteries in series, wind more turns of wire on the needle, and leave it +connected a little longer. Do the same thing with the second knitting +needle. In the same way, you can magnetize a screwdriver, so that you +can use it to pick up and hold steel screws. Don't do it unless you want +your screwdriver to be magnetized. + +[Illustration: Figure 3] + + +See How They Attract and Repel + +Take one of the magnetized needles and hang it with a thread. A thread +stirrup (Figure 4) will help keep it level. Be sure it is not near other +large pieces of steel. Watch the needle. Does it settle down, pointing +in one direction? (Check to see if this is the same direction as your +compass). If it does, you have made a compass. The tip of the needle +pointing north is called the North Pole (North-seeking pole). The other +end is called the South Pole. Mark the North Pole with a stroke of the +red marking pencil. Mark the South Pole black. Do the same thing with +the second needle. You can show this with a sewing needle, and a notched +cork, and a bowl of water. Rest the needle in the notched cork, and +float it on the water. + +[Illustration: Figure 4] + +Hold the compass near the North Pole of the needle. What happens? Does +the South Pole of the needle attract the North or South Pole of the +compass? Try this with the second magnetized needle. See if you can +prove the rule that like poles repel (drive away) and unlike poles +attract. + +[Illustration: Figure 5] + +Connect one end of a wire loop to the battery and run the wire directly +over the compass. Touch the other end of the wire to the battery. Which +way does the compass point now? If you get some motion out of the +compass needle, this proves there is a magnetic field around the wire +when current is flowing. This relation between electricity and magnetism +is the thing that makes electric motors and generators work. + +[Illustration: Figure 6] + + +Make Many From One + +Lay the third needle (unmagnetized) on a table and stroke it with one of +the magnetized needles. (See diagram) Always stroke it in the same +direction. Raise the magnetized needle at least two inches on each +return stroke. Thus you can magnetize the needle by using the other +needle. + +[Illustration: Figure 7] + +Use the wire cutters to cut the first magnetized needle in short +lengths. (Cover the needle with a cloth to keep the pieces from flying.) +Can you show by using the compass that each piece is a complete magnet? +Hold one end, then the other, of each piece to a compass. Does each +piece have both a North Pole and a South Pole? + + +Magnetism and Animals + +The things you have done show that electricity and magnetism are related +in many ways. Magnetism is mysterious, and there are still things to +discover about it. It is thought that animals and birds are aided in +their sense of direction by magnetism. It is commonly known that when a +person gets lost in the woods, he tends to go around in circles. +Possibly this is caused by the earth's magnetic field. + + +What Did You Learn? + +1. Where are natural magnets obtained? + +2. How can artificial magnets be made? + +3. What material is needed for a permanent magnet? For a temporary +magnet? + +4. How can you find out which is the North Pole of an unmarked magnet? + +5. How many poles does a magnet have? + +6. Which magnetic poles attract each other? + +7. Why couldn't you make a compass out of a strip of plastic? + +8. What causes the compass to change direction when a wire carrying +battery current is held over the needle? + +9. List the materials you would need and tell how you would build a +homemade compass. + +10. Tell what you enjoyed most about becoming acquainted with mysterious +magnetism. + + + + +LESSON NO. B-14 + +Credit Points 2 + +Give your appliances and lights a square meal + + +Would you say that having enough to eat was pretty important in the home +that you know? + +The "food" for your appliances and lights is electricity, and like you +they must be "fed" enough. + + +What to Do + +1. List the appliances and lights in your home. + +2. See if any of them are "starving" for the electricity they need. + +3. Learn how the electricity gets to where it's used. + +4. Make a chart of the electrical circuits in your home. + +5. Make sure that each circuit is protected with the right fuse or +circuit breaker. + + +Count Your Electrical Blessings + +Many people in much of the rest of the world wish that they could trade +places with us, because we have so many electrical appliances in our +homes. + +Of course, we have not always had as many appliances as there are today. +When electricity first came along, people used it only for lights. Then, +they began to add flatirons, washing machines, refrigerators, coffee +percolators, and radios. + +Then more and more electrical things were made for people to use and +enjoy. Now we have dozens and dozens of uses for electricity in our +homes. + +How many different uses for electricity are there in your home today? +Ask your parents how many there were when your home was built or first +wired. How many were _common_ when your parents began to keep house? + + +Some Homes Are Behind Times + +Many older homes were built before electricity was available, and were +wired later. And like them, some older homes that were wired as they +were built had only enough wiring for lights and a few other appliances, +because those were the only uses that were known at that time. + +But people kept on living in these homes, and kept adding to the uses +they made of electricity without adding to their wiring. + +What has this meant? Well, if electricity were like cars and trucks, you +could say that some people are trying to put turnpike traffic through a +back-country dirt road! + + +Watch for Signs of Starvation + +Of course, as your state has done with its highways, some people have +expanded and modernized their wiring. But many others have not yet seen +this need, or if they have, they may have to do it again. + +Here's why: + +Your power supplier delivers current to you at the right voltage or +electrical pressure. If the wires in your house are large enough, they +will pass this full voltage on to the appliances. + +But if your wiring is too small, the electricity arrives at the +appliances so weak that they can't work properly, and much of what you +pay for is wasted. + +Here are some things you can watch for in your own home. They will tell +you whether your appliances are getting enough electrical "food" or not. + +1. _A shrinking TV picture_--If it draws in from the sides of the +screen, fades, loses contrast, or if the sound becomes distorted, you +may have low voltage. + +2. _Too much fuse blowing or circuit breaker tripping._ + +3. _Heating appliances are slow to do their jobs._ + +4. _Lights dimming_, when motors or other appliances are turned on. + + +There Should Be Enough Ways to Get "Appliance-Food" Around + +If appliances in your home show these starvation signs, then you may not +have enough ways for the electricity to get to where it's used. + +There are three kinds of these electrical highways or circuits, and your +home should have enough of each: + +1. _General purpose circuits_--These serve lights all over the house, +and convenience outlets everywhere except in the kitchen, laundry, and +dining areas. + +A rule-of-thumb is: There should be at least one general purpose circuit +for each 500 sq. ft. of floor space. + +2. _Small appliance circuits_--These are not used for lights, but +instead they supply convenience outlets in the kitchen, laundry, and +dining areas where portable appliances are most used. + +Every home should have at least two small-appliance circuits. + +3. _Individual or special-purpose circuits_--One of these is needed for +each: electric range, dishwasher, water heater, freezer, automatic +washer, clothes dryer, air conditioner, pump, and house heating +equipment. + + +----------+------+------+------+------+-------+ + | | | | | | | + | Actual | | | | | | + | Size | | | | | | + +----------+------+------+------+------+-------+ + | Gauge | | | | | | + | Size | 14 | 12 | 10 | 8 | 6 | + +----------+------+------+------+------+-------+ + | Fuse or | | | | | | + | Breaker | 15 | 20 | 30 | 40 | 55 | + +----------+------+------+------+------+-------+ + |Max. Watts| | | | | | + |at 115 V. | 1725 | 2300 | 3450 | 4600 | 6325 | + +----------+------+------+------+------+-------+ + |Max. Watts| | | | | | + |at 230 V. | 3450 | 4600 | 6900 | 9200 | 12750 | + +----------+------+------+------+------+-------+ + +[Illustration: Wire sizes commonly used in homes] + + +Each Circuit Big Enough + +The capacity of each circuit is limited by the size of its wires. The +chart above shows you the actual sizes of wires commonly used in +permanent home wiring, and what each will carry. Notice that each size +is given a number, and the smaller the number, the bigger the wire. + +Also notice that a given size of wire will carry twice as many watts at +230 volts as it will at 115 volts. (Watts are figured by multiplying +amps times volts.) + +General purpose circuits usually are either Number 14 or Number 12 wire, +at 115 volts. What is the capacity of each, in watts? (Number 12 wire is +recommended for all new general purpose circuits.) + +Small appliance circuits are required to be at least Number 12 wire. + +Individual circuits are always sized according to the appliance they +serve. Find the size wire that should be used for a 10, 000-watt, +230-volt range; a 1500-watt, 115-volt dishwasher; a 4500-watt, 230-volt +clothes dryer. ________ ________ ________ + + +Only One Fuse Size Right + +A fuse in an electrical circuit is like an alert traffic +policeman--stopping everything if there's danger. A circuit breaker +serves the same purpose, and the right size is installed when the wiring +is done. + +A policeman uses his brain to tell him when to blow his whistle, but a +fuse depends on the size of the little fusible (meltable) metal link +that you see under the glass. + +If too great an electrical load is added to a circuit, this link will +melt and prevent a dangerous overload. If you put in a fuse with too +heavy a link, it will not melt in time, and the wiring and equipment may +be damaged. + +Therefore the right size of fuse is very important, and is something +that you should check in your own home. + +See the chart above for the right fuse for each size wire. + + +Make a Circuit Chart + +At one or more places in your home there is a box or panel containing +the fuses or breakers for the various circuits. Attached to the inside +of the door of each such panel should be a chart something like this: + +[Illustration] + + +-----+---------------------+-----------+ + | No. | Description | Fuse size | + +-----+---------------------+-----------+ + | 1 | Range | 40 | + +-----+---------------------+-----------+ + | 2 | Kitchen Outlets | 20 | + +-----+---------------------+-----------+ + | 3 | Dining Room Outlets | 20 | + +-----+---------------------+-----------+ + | 4 | Living Room Outlets | 15 | + +-----+---------------------+-----------+ + | | | | + +-----+---------------------+-----------+ + | | | | + +-----+---------------------+-----------+ + +Notice that in our chart we have made columns for a description of what +each circuit serves, its number or position in the panel, and the proper +size fuse for it. + +Because most such charts leave out this last very important bit of +information, you should make a complete new chart, like the one shown. +Provide as many lines as there are fuse positions. Paste or tape it to +the inside of the panel door. + +Then, ask permission of your parents to disconnect all the circuits by +unscrewing the fuses or flipping the circuit breakers. _Do not touch +anything but the fuse rim._ Then reconnect them, one at a time, to find +out what each circuit serves. Turn on as many lights as you can, to help +you in your detective work. Use a test lamp at those outlets that do not +have a light connected to them. Write two or three words describing each +circuit on the proper line on your chart. + +On a separate sheet, keep track of the appliances and lights that are on +each circuit, and add up the watts. (If the name-plate of any appliance +gives "amperes", "amps", or "A" instead of watts, just remember that +amps times volts equals watts.) This will tell you if any of them are +overloaded. Show this sheet to your parents. + + +Check the Wire Sizes + +_Disconnect the main switch_, and determine the size of the wires in +each circuit. Don't include the insulation in your measurement. + + +_BE CAREFUL! + +Even though you have disconnected the main switch, the wires coming into +it are still "live". So, do not touch any wires. Instead hold the wire +size chart near them so that you can tell which gauge each one is._ + +Write in the proper size fuse for each circuit on your chart. + + +Replace Any Wrong-Size Fuses + +Do the fuse sizes you have written on your chart agree with the ones +that are in place in the panel? + +Get the right size fuses and replace any that are wrong. Make sure that +you have a reserve supply of the right sizes, and that they are handy +for future use. + + +Talk it Over With Your Parents + +Do you think that your home has enough of the proper size circuits? If +not, talk it over with your parents. They may want to ask an electrician +to go over the wiring and make the necessary changes. + + +What Did You Learn? + +(Underline the right answer.) + +1. A (television set, radio) is very sensitive to changes in voltage. + +2. Dimming lights mean (static in the wires, an electrical overload). + +3. Wires that become warm from overload make it (more expensive, +cheaper) to operate the equipment. + +4. A home of 2,000 sq. ft. should have at least (three, four) general +purpose circuits. + +5. One solution to low voltage symptoms is (heavier fuses, more +circuits). + +6. Full capacity for a Number 14 wire circuit at 115 volts is (1725 +watts, 3000 watts). + +7. A room air conditioner should be on (a general purpose, an +individual) circuit. + +8. The purpose of a fuse is to (let you disconnect the circuit, +automatically prevent overloading the circuit). + +9. The right size fuse is determined by (wire size, the store where you +buy it). + +10. A circuit chart should give (circuit description and fuse size, the +maker's name). + + +Demonstrations You Can Give + +Ask your leader to help you plan a demonstration. You can show how +lights dim when too many other appliances are connected, how a fuse +protects against overloading, and the danger of using too large a fuse. + + +For More Information + +Ask your Extension agent, power supplier, or electrician for additional +help. + + + + +LESSON NO. B-15 + +Credit Points 4 + +YOU CAN MEASURE ELECTRICITY + + +Instruments that can detect or measure the flow of electricity have +helped to make possible the wonders of electricity as we know them +today. + +Scientists in laboratories must have measuring devices for experiments +leading to new uses of electricity. Power suppliers must have +instruments that tell what the generating equipment is doing and to +measure the amount of electricity being sold to users. Factories need +instruments that keep tab on electrical equipment to make sure +electricity is being used efficiently. + +In fact, almost anywhere you find electric power at work you'll find +electrical instruments--even in your home. The one you know best +measures the amount of electricity used. Another, in the family car, +shows whether the generator is charging the battery or if the battery is +discharging. + + +What to Do + +1. Make a simple kind of direct-current meter that will show you that +there's a magnetic field around a wire carrying an electric current and +that will detect a very tiny current. + +2. Make a more refined D.C. instrument (galvanoscope) and measure the +voltage of different sizes of dry batteries, and show how an electric +current can be induced. + + +Tools and Materials You'll Need: + + Pair of pliers, knife, small hammer + 30 feet of No. 24 bell or magnet wire + Compass + Two coins--a penny and a dime + Fine sandpaper + Blotting paper + Plastic or cellophane tape + Wooden blocks (See Figure 4) + Glue + 2 small nails + One #905 dry cell, a penlight battery, and + two regular flashlight batteries + Table salt + Drinking glass + 2 paper clips + Two machine bolts + + +How They Work + +Like many electrical things, most electrical instruments depend on the +action of magnetism created by an electric current. There is a magnetic +_field_ or lines of force around any wire carrying an electric current. +If this field is controlled and made to react on a sensitive device, +like an easily moved pointer, we have an electrical instrument. + + +Detect a Magnetic Field + +First, let's prove that there is a magnetic field around any wire +carrying an electric current. Take a piece of wire about two feet long +and scrape off about an inch of insulation from each end. Connect one +end to a battery terminal. Make a loop of wire that crosses the face of +your compass, north to south. Now touch the other end of the wire to the +other battery terminal. + +(DO NOT attempt to substitute alternating current, as from a model +railroad transformer because its alternating current will cause the +compass needle to swing rapidly from one side to the other.) + +[Illustration: Figure 1. + +Put your right hand beneath the wire so that your fingers point the way +the needle deflects, and your thumb will point in the direction that the +current is flowing.] + +What happens? Your compass needle should move to one side because it is +very sensitive to magnetic influences. This proved that the wire created +a magnetic field or lines of force when we passed electricity through +it. (Figure 1) + + +Detect a Tiny Current + +How sensitive is your simple electric meter? Take about five feet of +wire and wrap it around your compass as in Figure 2, keeping the turns +bunched together as much as you can. Leave about six inches at both ends +of the wire extended for leads. Scrape the insulation off the last inch +of both. Rotate the coil and compass until the needle and coil are +parallel, both pointing north and south. + +[Illustration: Figure 2] + +Take a copper penny and a dime, and clean off any corrosion or film on +the coin faces with a bit of fine sandpaper. Now take a piece of +blotting paper about the size of the penny and dip it into strong salt +water. Place the damp blotting paper between the penny and the dime. +Place one of your compass coil leads against the dime, and the other +against the penny as shown in Figure 3. Be sure you have good +metal-to-metal contact between the wires and the coins. + +[Illustration: Figure 3] + +At the instant that you squeeze the leads against the coins, watch what +is happening to the compass needle. It should move for an instant from +the north position each time you press the leads against the two coins. + +Obviously, the little coin battery you have just made produces a very +weak electrical current. Even so, your instrument should be able to +detect it. + + +Make a Simple Galvanoscope + +Now let's make a meter that is a little more practical to use. Broadly +speaking, a galvanoscope is an instrument that detects the presence of +electric currents. It sounds complicated but it is really quite simple. +It is named in honor of an Italian professor named Galvani who made +important early experiments with electricity. + +A refinement of the galvanoscope is today's galvanometer. Other related +instruments are the voltmeter and ammeter. These are very important +instruments to the electrical engineer. + +Using a glass or anything three to four inches in diameter, wind about +20 turns of wire in a "bunched" coil as in Figure 4. Wrap the coil at +several points with cellophane or plastic tape to keep it from +unwinding. + +[Illustration: Figure 4] + +Make a wood base for your coil as shown in Figure 4. The compass support +blocks can be thin wood slats. Do not attach them with steel nails or +tacks. Use glue instead. Hold the coil in the slot between the blocks +with glue or melted wax or use copper staples. Place the compass on the +supports and rotate the base so that the compass needle and coil are +parallel, pointing north and south. + + +Measure the Voltage of Batteries + +Do you know what difference the size of dry cell battery makes in the +voltage it supplies? Your meter can tell you. + +To test the voltage of batteries we must be able to control our +galvanoscope. To do this, connect a glass of strong salt water in series +with the battery as shown in Figure 5. Make sure the wire ends immersed +in the salt water are scraped free of enamel. + +[Illustration: Figure 5] + +With one of the batteries connected, move the wires in the salt water +first closer, then farther apart (keeping them parallel to each other) +while watching your compass needle. When the needle stays 15 to 20 +degrees off north, lock the wires in the salt solution in place with +paper clips. + +Now disconnect the battery you have been using and connect a smaller +battery. If both batteries are fresh, the compass needle should return +to almost the same spot. This proves that both batteries regardless of +size put out the very same voltage. The larger ones, however, are +designed to last longer. + + +Measure the Difference between Series and Parallel + +Using the salt solution as in the previous experiment, connect two +flashlight batteries in series as shown in Figure 6. The compass needle +should move about twice as far as it did with one battery connected. +This shows that when you connect batteries this way you double their +voltage. + +[Illustration: Figure 6] + +Now place your batteries side by side and connect the two top terminals +and the two bases as shown in Figure 7. The compass needle should move +only as much as it did for one battery. This is called a parallel +connection. You can see that this arrangement does not double the +voltage, even though you used two batteries. + +[Illustration: Figure 7] + +While you have this hookup, try reversing the position of the leads +connected to your batteries. Notice that reversing the direction of +current flow in the coil causes the compass needle to swing in the +opposite direction. + + +Test for Induced Current + +Make a simple coil by winding about 50 turns of wire around a machine +bolt core. The bolt should be 1/4 to 1/2" in diameter and about two +inches long. Connect the coil to your galvanoscope as shown in Figure 8. +Pass the coil back and forth close to the end of a permanent magnet. +[Illustration: Figure 8] + +Notice a slight deflection of the compass needle with each pass. You +have shown that electricity can be induced in a wire coil by moving it +through a magnetic field. Currents generated in this way are called +induced currents. + +[Illustration: Figure 9] + +Now make another coil and core just like the first one and arrange them +and a connection as shown in Figure 9. If you make and break the current +to the second coil, you will build up and collapse a magnetic field +around the first coil and again induce a current in it. You will see the +compass needle swing back and forth again. + +These last two experiments give you a crude idea of how an electric +generator works, producing electric current by induction as a coil-wound +rotor revolves within a magnetic field. + + +What Did You Learn? + +What does every current-carrying wire have around it? How does this help +us to measure electricity? How sensitive are electrical instruments? +What is the difference in voltage between (a) a large and a small dry +cell? (b) batteries connected in series and in parallel? (c) your +original connection and the reverse of it? What similarity does the test +for induced current show between movement through a magnetic field and +the making and breaking of a direct current? + + +Demonstrations You Can Give + +Show others how your galvanoscope can detect: whether a battery is +producing current, which way the current is flowing, and whether a +current is strong or weak. Demonstrate how a current can be generated +using magnetism. + + +For More Information + +Ask your power supplier representative to show you some of the +instruments used by his organization, and to give you a brief +explanation of how they work. Ask him or an electrician to give you a +demonstration of a split-core ammeter. + + + +***END OF THE PROJECT GUTENBERG EBOOK ELECTRICITY FOR THE 4-H SCIENTIST*** + + +******* This file should be named 38036-8.txt or 38036-8.zip ******* + + +This and all associated files of various formats will be found in: +http://www.gutenberg.org/dirs/3/8/0/3/38036 + + + +Updated editions will replace the previous one--the old editions +will be renamed. + +Creating the works from public domain print editions means that no +one owns a United States copyright in these works, so the Foundation +(and you!) can copy and distribute it in the United States without +permission and without paying copyright royalties. Special rules, +set forth in the General Terms of Use part of this license, apply to +copying and distributing Project Gutenberg-tm electronic works to +protect the PROJECT GUTENBERG-tm concept and trademark. 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Wilson</title> + <style type="text/css"> + + blockquote { + text-align:justify; + } + + body { + margin-left:10%; + margin-right:10%; + } + + .booktitle { + letter-spacing:3px; + } + + .center { + text-align:center; + font-weight:bold; + } + + div.center { + text-align:center; + } + + div.center table { + margin-left:auto; + margin-right:auto; + text-align:left; + } + + div.inset12, div.inset20, div.inset26 { + margin-top:1em; + margin-bottom:1em; + margin-left:auto; + margin-right:auto; + } + + div.inset12 { + width:12em + } + + div.inset20 { + width:20em + } + + div.inset26 { + width:26em + } + + div.inset12 p, div.inset20 p, div.inset26 p { + text-indent:0; + } + + .figcenter { + padding:1em; + text-align:center; + font-size:0.8em; + border:none; + margin:auto; + text-indent:1em; + } + + .h1 { + font-size:2em; + margin:.67em 0; + } + + .h1, .h2, .h3, .h4, .h5, .h6 { + font-weight:bolder; + text-align:center; + text-indent:0; + } + + h1, h2, h3, h4, h5, h6 { + text-align:center; + } + + .h2 { + font-size:1.5em; + margin:.75em 0; + } + + .h3 { + font-size:1.17em; + margin:.83em 0; + } + + .h4 { + margin:1.12em 0 ; + } + + .h5 { + font-size:.83em; + margin:1.5em 0 ; + } + + h5 { + margin-bottom:1%; + margin-top:1%; + } + + .h6 { + font-size:.75em; + margin:1.67em 0; + } + + hr.chapter { + margin-top:6em; + margin-bottom:4em; + } + + p { + text-align:justify; + margin-top:.75em; + margin-bottom:.75em; + text-indent:0; + } + + p.caption { + text-indent:0; + text-align:center; + margin-bottom:2em; + } + + p.hang { + margin-left:2em; + text-indent:-2em; + } + + p.margin20 { + margin-right:20px; + margin-left:20px; + } + + p.right { + text-align:right; + } + + p.spacer { + margin-top:2em; + margin-bottom:3em; + } + + .pagenum { +/* visibility:hidden; remove comment out to hide page numbers */ + position:absolute; + right:2%; + font-size:75%; + color:gray; + background-color:inherit; + text-align:right; + text-indent:0; + font-style:normal; + font-weight:normal; + font-variant:normal; + } + + .split { + float: left; + clear: left; + padding-right: 2%; + padding-left: 0; + padding-top: 0; + padding-bottom: 0; + } + + .splitr { + float: right; + clear: right; + padding-right: 0; + padding-left: 2%; + padding-top: 0; + padding-bottom: 0; + } + + .tdc { + text-align:center; + } + + .tdl { + text-align:left; + } + + .tdli { + font-style: italic; + text-align:left; + } + + .tdr { + text-align:right; + padding-right:1em; + } + + .topbox { + color:black; + border:2px solid black; + } + + .topbox400 { + width:400px; + color:black; + border:2px solid black; + } + + hr.full { width: 100%; + margin-top: 3em; + margin-bottom: 0em; + margin-left: auto; + margin-right: auto; + height: 4px; + border-width: 4px 0 0 0; /* remove all borders except the top one */ + border-style: solid; + border-color: #000000; + clear: both; } + pre.pg {font-size: 85%;} + </style> +</head> +<body> +<h1>The Project Gutenberg eBook, Electricity for the 4-H Scientist, by Eric B. +Wilson</h1> +<pre class="pg"> +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at <a href = "http://www.gutenberg.org">www.gutenberg.org</a></pre> +<p>Title: Electricity for the 4-H Scientist</p> +<p> Idaho Agricultural Extension Service Bulletin 396, June, 1962</p> +<p>Author: Eric B. Wilson</p> +<p>Release Date: November 16, 2011 [eBook #38036]</p> +<p>Language: English</p> +<p>Character set encoding: ISO-8859-1</p> +<p>***START OF THE PROJECT GUTENBERG EBOOK ELECTRICITY FOR THE 4-H SCIENTIST***</p> +<p> </p> +<h3>E-text prepared by<br /> + Kevin Handy, John Hagerson, Matthew Wheaton,<br /> + and the Online Distributed Proofreading Team<br /> + (http://www.pgdp.net)</h3> +<p> </p> +<hr class="full" /> +<p> </p> +<p> </p> + +<div class="figcenter topbox400"> +<img src="images/cover.jpg" width="400" height="510" alt="" /> +</div> + +<p class="spacer"> </p> + +<p class="h6">IDAHO Agricultural<br /> +Extension Service</p> + +<p class="spacer"> </p> + +<p class="h6">BULLETIN 396<br /> +JUNE, 1962<br /> +T-1</p> + +<p class="spacer"> </p> + +<h1 class="booktitle">ELECTRICITY for the 4-H scientist</h1> + +<p class="spacer"> </p> + +<p class="h3">Safety<br /> +Uses<br /> +Economy</p> + +<p class="spacer"> </p> + +<p class="h6">DIVISION I<br /> +4-H ELECTRIC</p> + +<p class="spacer"> </p> + +<p class="h4">UNIVERSITY OF IDAHO<br /> +<i>College of Agriculture</i></p> + +<hr class="chapter" /> + +<h2 id="How_to">HOW TO USE THIS BOOK IN FULFILLING THE GOALS OF THE 4-H ELECTRIC PROJECT +FOR THE FIRST AND SUCCEEDING YEARS</h2> + +<p>The minimum goals for credit in the +4-H Electric project vary according to the +4-H member's age and the number of years +he or she has taken the electric project. For +example, if you are a 4-H member beginning +the 4-H Electric project at the age of 10, +you will not be required to earn as many +credit points as a 14-year-old 4-H member +beginning the 4-H Electric project. However, +if you are a 12-year-old in your second +year of electricity you must earn as +many credit points in that year as a 14-year-old +does in his or her first year.</p> + +<p>Each lesson or goal has been designated +a certain number of credit points. These +are shown near the title of each lesson or +goal. You decide on the lessons you want +to study, list them, and add up the credit +points.</p> + +<p>For a full year's 4-H project credit, the +total of your credit points should be at least +as many as shown in the following table:</p> + +<p>Examples of reading the table below are +as follows: (a) An 11-year-old member is +required to complete 13 credit points the +first year, (b) A 14-year-old is required to +complete 17 credit points his first year, (c) +A 14-year-old taking the electric project for +the third year must complete 16 credit points +that year.</p> + +<p>We recommend that, if you are taking +the 4-H Electric project, you start with the +first lesson in the book and go on through +to the back of the book in advanced years. +But you may skip the less important or less +interesting parts so long as you learn the +basic lessons. A way to find out whether +you know the basic lessons is to read them +through and try to answer all questions +under the heading "What Did You Learn." +If you can answer these questions you may +not wish to spend the time doing the things +listed under "What To Do."</p> + +<p>Minimum Number of Credit Points +Required for Each Year's Work in the 4-H Electric Project</p> + +<p class="spacer"></p> + +<div class="center"> +<table border="2" cellpadding="4" cellspacing="0" summary="Year's Work"> + <tr> + <td class="tdl">4-H Member's Age</td> + <td class="tdc" colspan="4">4-H Member's Year in 4-H Electric Project</td> + </tr> + <tr> + <td class="tdl"> </td> + <td class="tdc">1st Year</td> + <td class="tdc">2nd Year</td> + <td class="tdc">3rd Year</td> + <td class="tdc">4th or<br /> Later Years</td> + </tr> + <tr> + <td class="tdl">10-11</td> + <td class="tdc">13</td> + <td class="tdc">15</td> + <td class="tdc"> </td> + <td class="tdc"> </td> + </tr> + <tr> + <td class="tdl">12-13</td> + <td class="tdc">15</td> + <td class="tdc">17</td> + <td class="tdc">19</td> + <td class="tdc">20</td> + </tr> + <tr> + <td class="tdl">14-15</td> + <td class="tdc">17</td> + <td class="tdc">19</td> + <td class="tdc">21</td> + <td class="tdc">21</td> + </tr> + <tr> + <td class="tdl">16 & over</td> + <td class="tdc">19</td> + <td class="tdc">21</td> + <td class="tdc">21</td> + <td class="tdc">21</td> + </tr> +</table></div> + +<p><br />This system of credit points makes it possible for you to do the things you want to do with +electricity and get credit for them in the 4-H Electric project.</p> + +<p class="spacer"> </p> + +<p class="h4">4-H Electric, Division I</p> + +<p class="spacer"> </p> + +<hr class="chapter" /> + +<h2>TABLE OF CONTENTS</h2> + +<div class="center"> +<table border="0" cellpadding="4" cellspacing="20" summary="Table of Contents"> + <tr> + <td class="tdr">Lesson<br />Number</td> + <td class="tdc">Title</td> + <td class="tdc">Credit<br />Points</td> + <td class="tdc">Page<br />Number</td> + </tr> + <tr> + <td class="tdr"> </td> + <td class="tdl"><a href="#How_to">How to Use This Book</a></td> + <td> </td> + <td class="tdc">1</td> + </tr> + <tr> + + <td class="tdr"><a href="#LESSON_NO_B-l">B-1</a></td> + <td class="tdl">Getting Acquainted With Electricity</td> + <td class="tdc">3</td> + <td class="tdc">2</td> + </tr> + <tr> + <td class="tdr"><a href="#LESSON_NO_B-2">B-2</a></td> + <td class="tdl">Tools for Electricians</td> + <td class="tdc">4</td> + <td class="tdc">7</td> + </tr> + <tr> + <td class="tdr"><a href="#LESSON_NO_B-3">B-3</a></td> + <td class="tdl">Rewire a Lamp—Be a Lamp Detective</td> + <td class="tdc">3</td> + <td class="tdc">11</td> + </tr> + <tr> + <td class="tdr"><a href="#LESSON_NO_B-4">B-4</a></td> + <td class="tdl">Make a Trouble Light</td> + <td class="tdc">3</td> + <td class="tdc">15</td> + </tr> + <tr> + <td class="tdr"><a href="#LESSON_NO_B-5">B-5</a></td> + <td class="tdl">What Makes Motors Run</td> + <td class="tdc">5</td> + <td class="tdc">18</td> + </tr> + <tr> + <td class="tdr"><a href="#LESSON_NO_B-6">B-6</a></td> + <td class="tdl">Taking Care of Electric Motors</td> + <td class="tdc">3</td> + <td class="tdc">23</td> + </tr> + <tr> + <td class="tdr"><a href="#LESSON_NO_B-7">B-7</a></td> + <td class="tdl">Reading the Electric Meter</td> + <td class="tdc">4</td> + <td class="tdc">26</td> + </tr> + <tr> + <td class="tdr"><a href="#LESSON_NO_B-8">B-8</a></td> + <td class="tdl">Ironing is Fun</td> + <td class="tdc">3</td> + <td class="tdc">30</td> + </tr> + <tr> + <td class="tdr"><a href="#LESSON_NO_B-9">B-9</a></td> + <td class="tdl">Let's Be Friends With Electricity</td> + <td class="tdc">2</td> + <td class="tdc">35</td> + </tr> + <tr> + <td class="tdr"><a href="#LESSON_NO_B-10">B-10</a></td> + <td class="tdl">How Electric Bells Work—For You</td> + <td class="tdc">3</td> + <td class="tdc">39</td> + </tr> + <tr> + <td class="tdr"><a href="#LESSON_NO_B-11">B-11</a></td> + <td class="tdl">First Aid for Electrical Injuries</td> + <td class="tdc">2</td> + <td class="tdc">43</td> + </tr> + <tr> + <td class="tdr"><a href="#LESSON_NO_B-12">B-12</a></td> + <td class="tdl">How Electricity Heats</td> + <td class="tdc">3</td> + <td class="tdc">47</td> + </tr> + <tr> + <td class="tdr"><a href="#LESSON_NO_B-13">B-13</a></td> + <td class="tdl">Mysterious Magnetism</td> + <td class="tdc">2</td> + <td class="tdc">50</td> + </tr> + <tr> + <td class="tdr"><a href="#LESSON_NO_B-14">B-14</a></td> + <td class="tdl">Give Your Appliances and Lights a Square Meal</td> + <td class="tdc">2</td> + <td class="tdc">54</td> + </tr> + <tr> + <td class="tdr"><a href="#LESSON_NO_B-15">B-15</a></td> + <td class="tdl">You Can Measure Electricity</td> + <td class="tdc">4</td> + <td class="tdc">58</td> + </tr> +</table></div> + +<p class="spacer"> </p> + +<p class="h5">UNIVERSITY OF IDAHO<br /> +COLLEGE OF AGRICULTURE<br /> +AGRICULTURAL EXTENSION SERVICE<br /> +Eric B. Wilson, Extension Agricultural Engineer<br /> +1962</p> + +<p>Published and distributed in furtherance of the Acts of May 8 and June 30, 1914, by the +University of Idaho Extension Service, James E. Kraus, Director; and the U. S. Department +of Agriculture, Co-operating.</p> + +<hr class="chapter" /> + +<p><span class="pagenum">[2]</span></p> + +<div> +<img src="images/electprog_logo.jpg" width="50" height="70" alt="" class="split" /> +<img src="images/4h_logo.jpg" width="60" height="60" alt="" class="splitr" /> +</div> + +<h2 id="LESSON_NO_B-l">LESSON NO. B-1</h2> + +<p class="h4">Credit Points 3</p> + +<p class="h3">GETTING ACQUAINTED WITH ELECTRICITY</p> + +<p>Electricity serves you best when you understand +how it works and use it properly. +As a 4-H member, you should know about +electricity and help to show others the way to +obtain its tremendous work-saving benefits as +well as how to use it with safety.</p> + +<p>A good way to think of electricity is to +compare it with water. It acts a lot like water. +However it is made of tiny parts of atoms +called electrons. When there are more than +the normal number of electrons in anything, +it is said to be negatively charged; when there +is a shortage of electrons, it is positively +charged. As water flows downhill, "seeking +it's level," electrons flow from negative to +positive, seeking to "balance" the charge.</p> + +<h3>Electrical Conductors</h3> + +<p>Even if you're never going to repair a +lamp or make a chick brooder, you should +know about conductors and insulators. This +is because you happen to be a fairly good +conductor of electricity. Electricity will pass +easily through you to other conductors—the +ground, for instance. When this happens you +may get a shock, burn, or serious injury. +But it doesn't ever have to happen, if you learn +to understand your friend, electricity.</p> + +<p>Silver, copper, iron, aluminum and many +other metals are very good conductors. +Water, acids, and salts are too. Electricity +passes over or through them very easily. +Like water pipes, the larger the conductor, +the more electricity it can carry. When conductors +are too small for the amount of +electrons trying to move over them, they get +hot, melt, may start fires. That's why wire +size is important.</p> + +<h3>Electrical Insulators</h3> + +<p>Insulators are the opposite of conductors. +Electricity has trouble passing through some +materials. Rubber, most plastics, dry wood, +oils and glass are some of the good insulators. +It's the amount and kind of insulation +that counts. If it has enough force, electricity +can pass through just about anything—even +jump gaps!</p> + +<p>Electricity, like water, flows along the +easiest paths. It is always trying to get to +the ground. The earth attracts it. It stays +on the wires unless a person, a wet branch, +or some other conductor gives it a path to +the ground. Do not touch any wire which +might be carrying electricity.</p> + +<div class="figcenter"> +<img src="images/p02_blackboard.jpg" width="300" height="275" alt="" /> +</div> + +<h3>Play It Safe</h3> + +<p>If you should touch a "hot" wire accidentally +and are standing on a dry piece of +wood, the conducting pathway to the ground is +not good and the electricity may keep running +along its wire. But do not touch some +other conductor with another part of your +body. This would complete a circuit through +your body and would be very dangerous. Always +make sure there is plenty of good insulation +material or plenty of distance between +you and anything which might be carrying +electricity.</p> + +<p>Remember, too, insulation is of little use +when it is wet. Dew, mist, rain, condensation, +a damp floor can change the whole picture. +If you understand electricity and how it +acts, you'll be safe enough, because you won't +take chances or expose yourself to injury.</p> + +<p><span class="pagenum">[3]</span></p> + +<h3>Electrical Terms</h3> + +<p><i>Alternating Current</i>—Usually referred to as +"AC," alternating current is current which +reverses its direction of flow at regular +intervals, 60 times a second.</p> + +<p><i>Direct Current</i>—"DC" current flows only in +one direction. Battery current is DC.</p> + +<p><i>Ampere</i>—Amperes are units by which the rate +of flow of electrical current (electrons) is +measured. An ampere is 6.3 billion electrons +passing one point in a circuit, in one second. +This compares with the way the flow of water +is measured in gallons per second.</p> + +<p><i>Volts</i>—A volt is a unit to measure the tendency +of electrons to move when they are +shoved. Voltage is the amount of "push" +behind the electrons. It's like water pressure +in a pipe. Home power lines carry 115 +volts (110 to 120 volts). For appliances +such as electric stoves, washers and driers, +a second 115-volt line should be added, giving +230 volts (220 to 240 volts).</p> + +<p><i>Watts</i>—Watts equal volts times amperes. +Light bulbs, electric irons and other appliances +are usually marked with the voltage +they require and the number of watts.</p> + +<p><i>Kilowatts</i>—Your electric bill usually reads +in kilowatt hours. A kilowatt is 1000 watts. +A kilowatt hour equals 1000 watts used for 1 +hour. One kilowatt equals about 1-1/3 horsepower. +A kilowatt is usually indicated by +"kw" and a kilowatt hour by "kwh."</p> + +<p><i>Circuits</i>—A closed circuit is one in which +the electricity is flowing, lighting a light, running +a motor, or some other appliance. The +circuit runs all the way from the place the +electricity is being generated to your home, +through the appliance or light bulb, and back +to the generator.</p> + +<p>Circuits are opened and closed by +switches. When the circuit is opened, the +electricity stops at the switch. Before working +on a switch, socket, fuse, or any part of +the wiring be sure to open the main switch. +The main switch is usually at the fuse box +or near it. Appliances should be disconnected +when you work on them. Everyone in the +family should know where the main switch is +so it can be pulled in case of accidents, fire, +flood, or windstorm damage.</p> + +<p><i>Fuses and Circuit Breakers</i>—These are the +safety valves of your electrical system. +The different electrical circuits in your home +are meant to carry only certain amounts of +electricity. Some carry only 15 amps, others +can carry 20 or more. They are marked to +show capacity.</p> + +<p>When a fuse burns out or a circuit breaker +opens, look for an overload of lights and +appliances on the circuit before you try to replace +the fuse or close the circuit breaker. +Without these safeguards, the overloaded +electric line will heat up and may start a fire. +Even if no fire starts, electricity will be +wasted and the homeowner will be paying for +electricity that's doing no good.</p> + +<p>Remember: If you ever have to replace +a fuse, pull the main switch first. Keep a +flashlight handy in your house. It seems that +fuses usually blow at night, and it doesn't pay +to stumble or fumble around electric wires +in the dark.</p> + +<div class="figcenter"> +<img src="images/p03_wateranalogy.jpg" width="400" height="230" alt="" /> +</div> + +<p class="spacer"> </p> + +<p><span class="pagenum">[4]</span></p> + +<h3>WHAT TO DO: Make A Circuit Board</h3> + +<p>So that you can show others how electricity +travels from here to there, and how it behaves +under different conditions, make an electric +circuit board.</p> + +<p class="hang"> +<b><i>Materials Needed:</i></b><br /> + Piece of 3/4" board about 4" x 6"<br /> + l-l/2-volt No. 6 dry cell battery<br /> + Two pieces of bell wire, each 24" long, one black, one white<br /> + Two 10-penny box nails (3")<br /> + Three 3-penny box nails (1")<br /> + Two small screws or carpet tacks<br /> + Two 2-inch rubber bands<br /> + Two miniature sockets with solder terminals<br /> + Two l-l/2-volt flashlight bulbs +</p> + +<p class="hang"> +<b><i>Tools Needed:</i></b><br /> + Ruler, pencils, hammer, pliers or vise. +</p> + +<p><b><i>Making the Board:</i></b></p> + +<p class="hang">1. Lay out the board with a pencil and ruler +as indicated in Figure 1.</p> + +<p class="hang">2. Bend the three-inch nail as shown in Figure +2, using pliers, vise and hammer.</p> + +<p class="hang">3. Pound the one-inch nails into the board for +a half-inch at points A, C, and D. Use the +three-inch nail to make a hole a half-inch +deep at B. Put the crank nail in this +hole and pound in a little farther. Attach +the lamp socket brackets at E and F. +Stretch the rubber band as in Figure 3.</p> + +<p class="hang">4. Lay out the electricity path, the circuit +(Figure 3). Use the black wire for the +positive side of the circuit (the center +pole of battery). Twist it around the +switch crank B, and the center pole of +battery. Run another piece to the outside +terminal of bulb socket at E. Run white +piece to negative pole of battery from the +other terminal at E.</p> + +<div class="figcenter"> +<img src="images/p04_fig1.jpg" width="232" height="175" alt="" /> +</div> + +<p class="caption">Figure 1 (Circuit Board)</p> + +<div class="figcenter"> +<img src="images/p04_fig2.jpg" width="222" height="93" alt="" /> +</div> + +<p class="caption">Figure 2 (Switch)</p> + +<p class="hang">5. Close the switch. The rubber band should +hold the switch nail tightly against nail at +C. Does the bulb light? __________ +If it doesn't, check the connections.</p> + +<p>Now you have a circuit—a closed circuit +when the electricity runs all the way from the +positive pole to the negative pole. The black +wire is the hot side, the live wire, because it +carries the full load of the battery up to the +bulb.</p> + +<p>Remember, battery current is direct current, +DC. In the case of alternating current, +AC, such as most homes and buildings use, +the electricity flows in first one direction and +then the other.</p> + +<div class="figcenter"> +<img src="images/p04_fig3.jpg" width="237" height="187" alt="" /> +</div> + +<p class="caption">Figure 3 (Closed Circuit)</p> + +<h3>Parallel Wiring</h3> + +<p>To make this circuit hookup, attach another +white wire to the negative pole of battery +and a terminal of the second flashlight +bulb. Run a black wire from the other terminal +to the switch terminal at C (Figure 4). +Close switch. Both bulbs will light.</p> + +<p>Trace the circuit. Electricity is going +equally to each bulb, the same amount that +went to the single bulb. The difference is that +the battery will last only half as long. It's like +a pail of water with two open spigots. The +pail empties twice as fast as it would with just +one spigot open. This type of wiring is called +parallel wiring. If one bulb is unscrewed, +the other will stay lit.</p> + +<p><span class="pagenum">[5]</span></p> + +<div class="figcenter"> +<img src="images/p05_fig4.jpg" width="237" height="185" alt="" /> +</div> + +<p class="caption">Figure 4 (Parallel Wiring)</p> + +<h3>Series Wiring</h3> + +<p>To do this, run the negative wire to one +terminal of the second bulb and attach a wire +from the other terminal to a terminal of the +first bulb. The other terminal connects with +the switch at C (Figure 5). This is series +wiring. If one bulb is unscrewed, the other +will fail to light because the circuit is broken +for both. Anything that breaks the circuit has +the effect of opening the switch.</p> + +<div class="figcenter"> +<img src="images/p05_fig5.jpg" width="237" height="180" alt="" /> +</div> + +<p class="caption">Figure 5 (Series Wiring)</p> + +<p>Show there is a circuit through the bulb +by screwing and unscrewing it. Also, "jump" +the socket by running the wire from C to the +other terminal of the bulb at E while it is unscrewed. +Bulb at F will light. Trace this +circuit.</p> + +<p class="spacer"> </p> + +<h3>SUGGESTED DEMONSTRATIONS</h3> + +<p>Using the Circuit Board, you can give +many demonstrations of the way electricity +flows, works and behaves.</p> + +<h3>Water And Electricity</h3> + +<p>To help others understand electricity +better, draw a water system on an electric +circuit board paralleling the circuit. For the +battery show a water tank, pipes instead of +wires, faucets instead of switches. Somewhere +on the board paste a comparison of +electrical terms with terms used in describing +water, such as the following:</p> + +<p class="hang"> <br /> +Wire equals Pipe<br /> +Volts equal Pressure<br /> +Amperes equal Rate of Flow - gallons per second<br /> +Watts equal Pressure times Rate of Flow<br /> +Switch equals Faucet<br /> +Current equals Flowing Water +</p> + +<p>Show how to figure the wattage that a circuit +protected by a 15 ampere fuse can handle. +Do it with actual things or cut-out pictures +of light bulbs, irons, toasters, coffee-makers, +etc.</p> + +<p>You know that Amperes times Volts equal +Watts. If the voltage is 115, a 15 amp circuit +can handle 115 volts times 15 amps, or 1725 +watts.</p> + +<p>The name plates on electric motors indicate +the amperage at full load. You can convert +this to watts, of course, by multiplying +amperage by the line voltage. Motors require +an additional amount of electricity when they +start. You need to allow for this fact, so fuses +will not blow or circuits trip when a motor is +turned on. You will learn more about this +when you study electric motors.</p> + +<p class="spacer"> </p> + +<h3>For More Information</h3> + +<p>Your leader has many other sources of +information about electricity and demonstrations +you can perform. Ask him. Also, +libraries have many books about electricity +and its history, which are very interesting and +useful. Maybe you can find an electrician, +someone from your power supplier, or an +equipment dealer who will talk to your club on +electricity or electrical safety.</p> + +<p class="spacer"> </p> + +<p><span class="pagenum">[6]</span></p> + +<h3>What Did You Learn?</h3> + +<p>(Underline the correct answers then discuss in +the group.)</p> + +<p>1. In a water pipe system water flows. In an +electrical circuit (electrons) (atoms) (charges) +flow.</p> + +<p>2. Electricity or electrons flow (easier) (harder) +(about the same) in a conductor than in an +insulator.</p> + +<p>3. Rubber is a good (conductor) (insulator) +(ground).</p> + +<p>4. The most common material used as an electrical +conductor is (glass) (silver) (copper).</p> + +<p>5. The unit of electrical pressure or push is +the (ampere) (volt) (watt).</p> + +<p>6. The rate of flow of electricity is measured +in (gallons) (amperes per minute) (amperes).</p> + +<p>7. Volts times amperes equals (watts) (kilowatt +hours) (alternating current).</p> + +<p>8. A dry cell battery (stores) (makes) (uses) +electrical energy.</p> + +<p>9. In a parallel circuit the electricity has (one) +(two or more) (no) paths to travel.</p> + +<p>10. In a series circuit with two bulbs and a +switch the bulbs are (brighter) (dimmer) (the +same) as when they were in the parallel circuit.</p> + +<hr class="chapter" /> + +<p><span class="pagenum">[7]</span></p> + +<div> +<img src="images/electprog_logo.jpg" width="50" height="70" alt="" class="split" /> +<img src="images/4h_logo.jpg" width="60" height="60" alt="" class="splitr" /> +</div> +<h2 id="LESSON_NO_B-2">LESSON NO. B-2</h2> + +<p class="h4">Credit Points 4</p> + +<h3><b>TOOLS FOR ELECTRICIANS</b></h3> + +<div class="inset12"> +<p>Who goeth a borrowing<br /> +Goeth a sorrowing<br /> +Few lend (but fools)<br /> +Their working tools</p> +<p class="right">Tusser 1524-1580</p> +</div> + +<p>Whenever a job comes up, it saves time +and trouble when you have the right tools +and they are all where you can find them. +Electrical work takes some special tools +and some everyday tools.</p> + +<p>If you have ever watched a good electrician +at work, you've seen how neatly he +stores his tools in a box so every one +of them is handy. When a lineman climbs a +pole, he has his regular tools in a holster on +his belt. Special tools are kept in a box in +racks in the repair truck, all ready for instant +use. Wouldn't you like to have electrician's +tools all handy, ready for use, and +know how to use them properly?</p> + +<h3>Basic Tools for Electrical Work</h3> + +<div class="figcenter"> +<img src="images/p07_tools.jpg" width="350" height="103" alt="" /> +</div> + +<p><i>Knife</i></p> + +<p>A good knife with a sharp blade is one of +the most useful tools. A camper's or electrician's +type knife is probably best because +it has other useful parts besides the cutting +blades—a screwdriver or punch, for instance. +Of course, you'll never use the cutting blades +as a screwdriver. This knife should be kept clean, +dry, sharp, and free from rust. Put +a little oil on the joints from time to time. +Remember, "Never whittle toward you and +you'll never cut yourself."</p> + +<p><i>Pliers</i></p> + +<p>A pair of electrician's pliers should be +part of your kit. Wrap the handles with +plastic insulating tape. Even though you're +not going to work on "hot" electric lines, +it pays to play safe. Later on, as you learn more +about electricity, you'll want a pair of +needle-nose pliers for the fine work.</p> + +<p><i>Screwdrivers</i></p> + +<p>You'll want a screwdriver which has true +corners. A 4 to 6 inch plastic handled screwdriver +with a narrow blade is best. You'll +probably need more than one size to fit the +various size screws you'll be turning.</p> + +<p><span class="pagenum">[8]</span></p> + +<p>Screwdrivers are easily damaged if you +try to use them as chisels and pry bars, or +use them in screw slots which are too large +for the blade.</p> + +<p>You can be hurt by the screwdriver if +you try to screw or unscrew things you are +holding in your hand. Keep your free hand +away from the end of the screwdriver. Place +the work on a bench or where it can be +handled easily.</p> + +<p><i>Soldering Iron</i></p> + +<p>A good 100 to 250-watt electric soldering +iron will be useful. Later on you may want +to buy a soldering gun, but unless you are doing +a lot of soldering it won't be necessary. +A supply of resin-core electrician's solder +will be needed. Acid-core solder reacts +with copper and in time causes a bad splice.</p> + +<div class="figcenter"> +<img src="images/p07_soldering.jpg" width="287" height="295" alt="" /> +</div> + +<p><i>Tape</i></p> + +<p>Once it was necessary to use two types of +tape on splices—rubber tape with friction +tape over it. Now there is a plastic tape on +the market which takes the place of both and +has good insulating quality. It is called +electrical tape, or plastic tape, and resists +water, oils (which would damage rubber tape), +and acids. You'll need a lot of tape in your +electrical work, so keep a roll on hand.</p> + +<p><i>Other Tools and Equipment</i></p> + +<p>As you go along in electrical work, you'll +be adding tools and other equipment, such as +a trouble light and maybe an ammeter or +voltmeter. Other tools you'll want to add will +be a Phillips screwdriver, open end wrenches, +a crescent wrench, small hack saw, hand drill +and bits.</p> + +<p>You'll also be using some regular carpenter's +tools such as hammers, saws, and so on. +Unless you use them frequently, you don't +need to keep them in your electrical kit.</p> + +<p>It's a good idea to start acquiring a supply +of electrical parts—lengths of wire, fuses, +switches, sockets, plugs, and other items that +will come in handy. There are parts you can +salvage from old lamps, motors, and other +equipment. Such a collection can be a real +treasure chest when you need a part in a +hurry. But be sure to throw away all faulty +parts.</p> + +<div class="figcenter"> +<img src="images/p08_fig1.jpg" width="212" height="175" alt="" /> +</div> + +<p class="caption">Figure 1. Completed tool chest.</p> + +<p class="spacer"> </p> + +<h3>WHAT TO DO: Build a Tool Chest</h3> + +<p>To keep your tools always ready for use, +a tool chest will be very handy. It's the 4-H +way to work. You'll be surprised how much +easier it makes a job when you have your +tools, various parts and repair equipment all +in one place. You can make the chest (Figure 1) +with a saw, plane, screwdriver, pencil, +ruler or carpenter's square, and hammer.</p> + +<p><i>Materials You'll Need:</i></p> + +<p class="hang">A piece of lumber 1" by 10" by 8 feet +long. (1" lumber is actually only 3/4" thick—this +is the thickness you'll be working with.)<br /> +2 small hinges, with wood screws<br /> +1 small hasp, with wood screws<br /> +2 small handles with wood screws, or one +large handle<br /> +1 small chain, 10" to 12" long<br /> +Some No. 6 penny finishing nails or wood +screws about the same length</p> + +<p><i>Making The Chest:</i></p> + +<p>1. Cut your lumber into the following +pieces:</p> +<p><span class="pagenum">[9]</span></p> +<p>1 piece 10" x 18" for top</p> + +<p>1 piece 8-1/2" x 16-1/2" for bottom</p> + +<p>2 pieces 6" x 8-1/2" for two ends</p> + +<p>2 pieces 6" x 18" for front and back</p> + +<p>2. Lay out pieces as shown in Figure 2.</p> + +<div class="figcenter"> +<img src="images/p09_fig2.jpg" width="212" height="160" alt="" /> +</div> + +<p class="caption">Figure 2.</p> + +<p>Then, set up the two end pieces and nail +to bottom section. Refer back to Figure 1 as +you go along to see that box is shaping up as +shown. Nail the front and back sections to +the ends along the bottom. Wood screws can +be used instead of nails.</p> + +<p>3. Lay the top in place and attach hinges +to the back side, about two inches in from +each end.</p> + +<p>4. Attach one part of hasp to the top, and +the other part to front board in center. Fasten +the handles to each end.</p> + +<p>5. Attach chain to the top and front so the +top will stay open when chain is fully extended.</p> + +<p>Now you can invent your own improvements +for your chest. You can paint it, put +your name on it, and your club emblem and +name if you wish. You can put a rack on the +inside of the cover to hold your work sheets +and other booklets and materials. You can install +special slots or straps to hold each tool +in its place along the sides of the box. Maybe +you will want to put some partitions in the +box to separate various electrical equipment +such as wires, fuses, switches, and plugs.</p> + +<p><i>A Working Kit</i></p> + +<p>An accessory which you may want to add +to your tool chest is an apron or holster to +wear when you are moving around on the job. +An apron can be made of a size of cloth about +18 by 20 inches. It should be folded up from +the bottom, and sewn to fit the number and size +of tools you have. Figure 3 shows such an +apron.</p> + +<div class="figcenter"> +<img src="images/p09_fig3.jpg" width="225" height="155" alt="" /> +</div> + +<p class="caption">Figure 3. Apron</p> + +<p>You can make a lineman's holster in the +same way, using plastic or soft leather. +Merely make belt loops by cutting on the +dotted lines. A snap fastener will hold the +flap over the tools so they won't fall out.</p> + +<div class="figcenter"> +<img src="images/p09_fig4.jpg" width="175" height="163" alt="" /> +</div> + +<p class="caption">Figure 4. Lineman's Holster.</p> + +<p class="spacer"> </p> + +<p><span class="pagenum">[10]</span></p> + +<h3>Demonstrations You Can Give</h3> + +<p>Show and tell others the proper handling, +care and use of tools.</p> + +<p>Show and tell how to build an electrician's +tool kit.</p> + +<p class="spacer"> </p> + +<h3>For Further Information</h3> + +<p>Ask your power supplier or an electrician +to tell the club about the various tools of the +electrician's trade and demonstrate them. +Ask your leader how to get exhibit material +or information about electrical tools and their +use and then tell the club about them.</p> + +<hr class="chapter" /> + +<p><span class="pagenum">[11]</span></p> + +<div> +<img src="images/electprog_logo.jpg" width="50" height="70" alt="" class="split" /> +<img src="images/4h_logo.jpg" width="60" height="60" alt="" class="splitr" /> +</div> + +<h2 id="LESSON_NO_B-3">LESSON NO. B-3</h2> + +<p class="h4">Credit Points 4</p> + +<p class="h3"><b>REWIRE A LAMP—BE A LAMP DETECTIVE</b></p> + +<div class="figcenter"> +<img src="images/p11_lineup.jpg" width="400" height="133" alt="" /> +</div> + +<p class="caption">The Line-Up Of Lamp Suspects</p> + +<p>One of the duties of a law officer is to +prevent crime. It's that way with the +lamp detective. You can become one. In the +average home there are lamps about to commit +the crime of shocking people, starting +fires, and stealing electricity. Some are refusing +to do their job well and some are no-goods, +sitting in closets or attics, doing +nothing. You can put these lamps to working +again safely and well. Become the lamp expert +in your family.</p> + +<h3>What's In A Lamp?</h3> + +<p>A lamp gives light for comfortable and +convenient use in the home. It consists +normally of a stand, switch, cord, lampshade +holder, and shade. Some lamps have diffusing +bowls which reduce glare and shadows.</p> + +<p>The most common fault found in an old +lamp is in the cord, but sometimes the +switch or the wiring in the lamp is bad. Look +over all the lamps in your home and find +the ones needing to be fixed.</p> + +<h3>WHAT TO DO—Rewire A Lamp</h3> + +<p>Somewhere around your house you can +probably find a lamp that is no longer used or +needs repairing. You can make it useful again +and at the same time learn how to wire a lamp.</p> + +<p><i>Materials Needed</i>:</p> + +<p>Tools: Pocket knife, small or medium +screwdriver, and pliers (electrician type is +best).</p> + +<p><i>New Lamp Cord</i>: For each lamp to be rewired, +you'll need 6 feet of cord plus the +length of wire within the lamp stand. Lamp +cord wire comes in two sizes, No. 18 and No. +16 AWG (American Wire Gauge). No. 18 is +smaller than No. 16, but is adequate for most +lamps. Cords are made with surface coverings +of several different materials: braided +cotton, rayon or silk, and molded rubber or +plastic. Braided cord is decorative, but rubber +or plastic is easier to work with and is +usually more desirable.</p> + +<p><i>Switch</i>: If the switch is bad, get a new one. +Socket switches are made with push-through, +turn-knob, or pull-chain controls. The pull-chain +type is seldom used on modern table or +floor lamps. Your lamp may have a separate +push-switch in the base. In this case, get the +same kind for replacement. Some switches +are "3-circuit" switches for use with high, +medium, and low-light bulbs.</p> + +<p><i>Plug</i>: Plugs are made of various materials, +mostly hard rubber or molded plastic. +Some have a shank or handle for better grasping. +This type is more desirable. The plug +on the old cord may be good, and if so, may +be used on the new cord.</p> + +<h3>How To Do It:</h3> + +<p>1. If the plug on the old cord is good and you +plan to use it, remove it from the old cord.</p> + +<p>2. Measure and cut a new lamp cord equal to +the length of the cord within the lamp, plus +6 feet.</p> + +<p><span class="pagenum">[12]</span></p> + +<p>3. Pass one end of the new cord through the +center of the plug. Strip 2 inches of the +fabric insulation off cord, or in case of a +rubber cord, split cord back two inches. Be +sure no bare wire shows in long split section +(Figure 1).</p> + +<p>4. Use knife to strip insulation off wire for +3/4" on end of each cord. Be careful. Don't +cut yourself. Don't cut wires. Use a light +touch, slope the knifeblade and slice with knife +edge away from you (Figure 1).</p> + +<div class="figcenter"> +<img src="images/p12_fig1.jpg" width="237" height="100" alt="" /> +</div> + +<p class="caption">Figure 1 (Ready to Wire Plug)</p> + +<p>5. Twist exposed strands of each wire tightly +to make a good conductor, and place each +conductor around its proper terminal in the +direction in which the screw tightens (Figure 2).</p> + +<p>6. Tighten screws on terminal posts. Pull +cord until slack is out. Lay aside until ready +to attach to lamp.</p> + +<div class="figcenter"> +<img src="images/p12_fig2.jpg" width="237" height="150" alt="" /> +</div> + +<p class="caption">Figure 2 (Attaching Cord to Plug)</p> + +<p>7. Remove lamp shade, shade-holder, bulb, +and diffusing bowl, if there is one.</p> + +<p>8. Separate the metal shell of socket from its +cap by pressing on shell at place marked +"press," and pull socket from cap.</p> + +<p>9. Pull on socket body to get some slack in +lamp cord. Loosen screws and detach cord. +Pull cord out through base of lamp. You can +splice new cord to the old one and use the +latter to "string" the new wire.</p> + +<p>10. Pass the new cord up through the lamp +base and socket cap, tie a simple half-hitch +knot in the cord to prevent strain on +the terminals, and attach wires to the terminals +on the socket (Figure 3). If there is +likely to be any strain on cord, use an Underwriters' +knot. Twist strands and attach wire +in direction in which screw tightens.</p> + +<p>11. Pull slack out of cord in lamp so that +socket rests in socket cap, replace shell and +reconnect cap. Be sure the fiber insulator +is in the shell. You'll feel or hear a click +when the notches in shell are locked to the +projections in the cap.</p> + +<p>12. Replace bulb, inspect carefully, and test. +(In floor lamps where the cord runs through +the center post and out under the base, the +cord will last longer if it is fastened with +tape so it doesn't rub edge of lamp base +when lamp is moved.)</p> + +<p>13. If the lamp has a porcelain socket, +simply disconnect the wires at the terminals, +remove the old wire and connect the +new one.</p> + +<div class="figcenter"> +<img src="images/p12_fig3.jpg" width="175" height="325" alt="" /> +</div> + +<p class="caption">Figure 3 (Socket and Switch Assembly)</p> + +<p><span class="pagenum">[13]</span></p> + +<h3>What Did You Learn?</h3> + +<p>Underline correct answers then discuss in the +group. (There may be more than one correct +answer.)</p> + +<p>1. The part of the lamp that usually wears +out first is (the socket) (the cord) (the +plug).</p> + +<p>2. Lamps that waste electricity are those +which have (bad wiring) (frayed cords) (dirty +shades or bulb).</p> + +<p>3. To unplug a lamp you should grasp (cord) +(plug) firmly and pull.</p> + +<p>4. Wire in lamp cord usually comes in sizes +16 or 18. Size 16 is the smaller (true) (false).</p> + +<p>5. In fastening wire around a terminal post +it should go around in a (clockwise) (counter-clockwise) +direction.</p> + +<p>6. When the switch on a lamp is turned off, +the electricity only goes as far as (the wall +plug) (the switch).</p> + +<p>7. An Underwriters' knot should be used +(only when there is room for it in the plug) +(whenever there is likely to be strain on the +cord, even if you have to replace the plug +with a larger one).</p> + +<h3>SUGGESTED DEMONSTRATIONS</h3> + +<p>Show how to inspect a lamp and its cord. +You might tie tags on the cord and lamp at +points of danger or failure—at the plug, +wear points next to lamp base, bad sockets.</p> + +<p>Demonstrate the process of repairing a +lamp cord, socket and plug.</p> + +<p>Make a board display of the parts of the +lamp socket showing cord attached.</p> + +<p>Make a display of the types of lamp cords +and plugs in common use.</p> + +<p>Using two lamps, one with clean bulb and +shade, the other dusty, show how the former +gives more light.</p> + +<h3>For More Information</h3> + +<p>Lamps have an interesting history. Look it +up in your local library. Ask someone from +your power supplier or electric dealer to talk +to the club about the different kinds of lamps. +Your leader has or can get additional information +on lamps, if you wish.</p> + +<div class="figcenter"> +<img src="images/p13_violation.jpg" width="250" height="188" alt="" /> +</div> + +<p><span class="pagenum">[14]</span></p> + +<p>What Did You Exhibit</p> + +<p>What Did You Demonstrate</p> + +<hr class="chapter" /> + +<p><span class="pagenum">[15]</span></p> + +<div> +<img src="images/electprog_logo.jpg" width="50" height="70" alt="" class="split" /> +<img src="images/4h_logo.jpg" width="60" height="60" alt="" class="splitr" /> +</div> + +<h2 id="LESSON_NO_B-4">LESSON NO. B-4</h2> + +<p class="h4">Credit Points 3</p> + +<h3><b>MAKE A TROUBLE LIGHT.</b></h3> + +<p>A handy piece of equipment in the home +and on the farm is a heavy-duty extension +cord with a shielded light and a side +outlet on it. When you want to work on the car +or tractor in the yard at night, the trouble +light is better than a flashlight. You can use +it both for light and as an extension cord. It +is safer than matches or a lantern, especially +around the garage or barn.</p> + +<p>It is easy to make a trouble light, and it +gives you good practice in electrical work. +Of course you can buy one, but you wouldn't +have the fun of making it nor would it suit +your needs. Trouble lights are not for permanent +use—they're for emergency use and +to provide light or electricity in places where +they are seldom needed. When you find a +trouble light being used as permanent wiring, +that's the place to install an outlet.</p> + +<h3>What Size Cord?</h3> + +<p>Choose the right kind of cord. What length +will be best for your various uses? A cord +too long may be bothersome to use and store. +What will be the heaviest load you are likely +to put on the cord, in amperes? Check appliances +you may want to connect to it. No. 16 +wire can carry 10 amperes safely for a distance +of 50 feet, while No. 18 can carry only +up to 7 amperes for a distance of 40 feet. +You'll want a "hard service" cord, called S, +ST, or SO-type cord by electricians. Junior +hard service cords, known as SJ, SJT, or +SJO, are fine for lighter duty.</p> + +<h3>Cord, Plug and Guard</h3> + +<p>A rubber-handled socket should be used +for safety and to withstand hard knocks. It +should have a switch on it, preferably a push +switch in a recess in the handle.</p> + +<p>The connector or attachment plug should +be of rubber or solid plastic and have a metal +cord grip fastened to it. This grip will hold +the cord firmly and prevent strain on the +terminal connections.</p> + +<div class="figcenter"> +<img src="images/p15_trouble.jpg" width="175" height="163" alt="" /> +</div> + +<p class="caption">Finished Trouble Light</p> + +<p>Get a good lamp guard. If the wire is too +light, it may bend and break the bulb when +hit or dropped. For the lamp itself, get a +rough service lamp. An ordinary lamp won't +last long with rough usage.</p> + +<h3>How to Make the Trouble Light</h3> + +<p><i>Tools Needed:</i></p> + +<p>Your 4-H electrician's kit or screwdriver, +knife and soldering iron</p> + +<p><i>Materials Needed:</i></p> + +<p>1. About 20 feet of 2-wire, No. 16 heavy +duty (hard service)</p> + +<p>2. A rubber-handled socket with switch +and a side outlet</p> + +<p>3. A shielded lamp guard</p> + +<p><span class="pagenum">[16]</span></p> + +<div class="figcenter"> +<img src="images/p16_materials.jpg" width="237" height="130" alt="" /> +</div> + +<p class="caption">Materials Needed</p> + +<p>4. A good connector plug cap, preferably +with a clamp-type grip for the cord</p> + +<p>5. A rough service lamp bulb</p> + +<p>6. Solder and flux</p> + +<p><i>Steps to Take:</i></p> + +<p>1. Remove about 2 inches of the outer +covering of cord at one end.</p> + +<p>2. Separate the wires and cut away the +filler material.</p> + +<p>3. Remove 3/4 inch of the conductor insulation +from the end of each wire and +tightly twist the strands together to +form a firm conductor. Be careful not +to cut any of the fine wires. Ends may +be soldered.</p> + +<p>4. Slide the plug in position on the cord.</p> + +<p>5. If there is no cord grip, tie the underwriters' +knot (Figure 1). If there isn't +room enough, make an "S" loop by +passing the wires around the prongs +before fastening them to the terminal +screws as explained in the next step.</p> + +<p>6. Loop the bare part of the wire around +the screw in the direction the screw +is turned to tighten (clockwise direction). +This will prevent the wires +from being forced out from under the +head of the screw as it is tightened. +Now repeat with the second wire, +wrapping it around the other prong of +the plug.</p> + +<p><i>Connecting the socket.</i></p> + +<p>1. Separate the parts of rubber-handled +socket (Figure 2).</p> + +<p>2. Prepare the other end of the cord as +in steps 1, 2, and 3 above.</p> + +<p>3. Insert the cord through the rubber +handle and socket guard.</p> + +<p>4. Tie the holding knot (underwriters' +knot) as explained in Step 5.</p> + +<p>5. Connect wires to terminal screws and +assemble the rubber-handled socket.</p> + +<p>6. Screw in the rough service lamp and +test your cord.</p> + +<p>7. Put the shielded lamp guard on the +socket and tighten the holding clamp +until it is firmly in place. You are +now ready to use or demonstrate your +trouble light.</p> + +<p>8. After you've made your trouble light, +decide on a good place to keep it where +it will be handy for use. Loop it carefully +and hang it over a wooden dowel +rather than a nail. It will last longer.</p> + +<div class="figcenter"> +<img src="images/p16_knot.jpg" width="187" height="267" alt="" /> +</div> + +<p class="caption">Figure 1 Tying an Underwriter's Knot</p> + +<p><span class="pagenum">[17]</span></p> + +<div class="figcenter"> +<img src="images/p17_fig2.jpg" width="187" height="120" alt="" /> +</div> + +<p class="caption">Figure 2 Disassembled Light</p> + +<h3>What Did You Learn?</h3> + +<p>(Underline correct answer)</p> + +<p>1. A Junior Hard Service Cord is known as +an (SO-Type) (SJO-Type) cord.</p> + +<p>2. You disconnect a cord by (jerking it from +the socket) (grasping plug and pulling it +out).</p> + +<p>3. Brass sockets are unsafe because (they +break too easily) (the exposed metal can +cause short circuits).</p> + +<p>4. Rubber-covered cord is safer for emergency +cords than fabric because (it will +stretch) (it will insulate and protect the +wires inside).</p> + +<p>5. In a trouble light (any kind of bulb will +do) (a rough service bulb is best).</p> + +<h3>Ideas for Demonstrations and Exhibits</h3> + +<p>1. Show how to make your trouble light and +a method of storing it.</p> + +<p>2. Show a safe trouble light, and an unsafe +trouble light with danger points marked.</p> + +<p>3. Show cutaway pieces of different types of +cord.</p> + +<h3>For More Information</h3> + +<p>Ask your power supplier, county highway +engineer, police official or leader to tell you +about various types of portable emergency +lights and their uses.</p> + +<hr class="chapter" /> + +<p><span class="pagenum">[18]</span></p> + +<div> +<img src="images/electprog_logo.jpg" width="50" height="70" alt="" class="split" /> +<img src="images/4h_logo.jpg" width="60" height="60" alt="" class="splitr" /> +</div> + +<h2 id="LESSON_NO_B-5">LESSON NO. B-5</h2> + +<p class="h4">Credit Points 5</p> + +<h3><b>WHAT MAKES MOTORS RUN</b></h3> + +<p>What makes an electric motor run? Can +you make an electric motor that will +run? Certainly you can, and by doing so +you'll learn why it runs. It won't be mysterious +any more and you'll be ahead of all +the millions of people who use motors every +day and never know why or how the motor +converts electrical energy into useful +power.</p> + +<div class="figcenter"> +<img src="images/p18_makingmotor.jpg" width="212" height="200" alt="" /> +</div> + +<h3>Motors Are Magnets</h3> + +<p>You know how one end of a compass +needle always points to North. No matter +how you turn the compass, the same end of +the needle always swings to the North. The +earth itself and that small compass are +both magnets (Figure 1). Each has a North +pole and a South pole. Around the poles of +each there are magnetic fields, invisible +lines of force that attract and repel.</p> + +<div class="figcenter"> +<img src="images/p18_fig1.jpg" width="225" height="138" alt="" /> +</div> + +<p class="caption">Figure 1. The same end of the compass needle always points to the earth's magnetic North Pole.</p> + +<p>The N poles <i>repel</i> each other and so do +the S poles. The N and S poles <i>attract</i> each +other. In other words, opposite poles attract; +poles that are alike repel each other.</p> + +<p>Lay 2 bar magnets on a table side-by-side. +If both N poles are at one end, they'll +repel each other and almost flip around until +there's a N pole lying next to a S pole +(Figure 2).</p> + +<div class="figcenter"> +<img src="images/p18_fig2.jpg" width="110" height="145" alt="" /> + +</div> + +<p class="caption">Figure 2. Small bar magnets laid side by side move +so that the North pole of one is near the South pole +of the other.</p> + +<p>Now suppose we place one of the bar +magnets on the table. The other, we'll fix +on a pivot so it can spin around. This one +we'll move so its N pole almost touches the +fixed magnet's N pole. As soon as we release +it, the movable magnet will spin around +so its S pole will be near the N pole of the<span class="pagenum">[19]</span> +stationary magnet. That's an electric motor—almost.</p> + +<div class="figcenter"> +<img src="images/p19_fig3.jpg" width="175" height="125" alt="" /> +</div> + +<p class="caption">Figure 3. A movable bar magnet pivots so its South pole is near the North pole of a stationary magnet.</p> + +<p>It's not quite a motor because the rotating +magnet will just move as far as it +has to in order to get the opposite poles +together. You might be able to cause the +movable bar magnet to make turn after +turn. You could do this by turning the fixed +magnet quickly end for end. This wouldn't +be very practical as a motor.</p> + +<h3>We Can Improve It</h3> + +<p>If we could change the pole on one end of +the rotating magnet just as soon as it +reaches the attracting pole, it could make +a complete circle. In doing that, the pole +at the near end of the rotating magnet would +be repelled by the stationary magnet and +pushed away. As soon as the opposite end +of the rotating magnet would come into the +magnetic field, it would be drawn to the +stationary magnet. In order to keep the +"motor" running, we would have to constantly +change the poles at each end on +every half revolution.</p> + +<h3>We Need An Electromagnet</h3> + +<p>We can't reverse the poles on simple +bar magnets, but we can on <i>electromagnets</i>. +We can make one by wrapping a wire several +times around an iron core to form a coil. +This magnet will also have a N and a S pole +when connected to electrical current. The +big difference is that the poles can be +changed instantly by reversing the current +in the wire.</p> + +<h3>Switching Poles Automatically</h3> + +<p>The rotating electromagnet will have to +be connected to the 2 wires through which +we pass the current. Since it's rotating on +a center shaft, we can't have a solid connection. +Instead we have to extend the +wires from the coil out along the shaft and +let the electric contact be made with +brushes which touch the wires along the +shaft.</p> + +<div class="figcenter"> +<img src="images/p19_fig4.jpg" width="250" height="150" alt="" /> +</div> + +<p class="caption">Figure 4. A rotating electromagnet changes poles as contacts are made first one way, then the other.</p> + +<p>This is a simple way to reverse the current +in the coil of the electromagnet.</p> + +<h3>Increasing Efficiency</h3> + +<p>Instead of using only one pole of a +stationary magnet, we can use both. This +is done by shaping the stationary magnet +around the path of the rotating electromagnet. +This way we have the benefit of +the attracting and repelling forces from +both poles. The effect is doubled.</p> + +<p>We can also wrap wires around this +circular iron and make an electromagnet +of it. But when we wire this magnet we +use no brushes because we want the current +to flow in one direction only.</p> + +<p>The stationary electromagnet is called +the <i>field</i>. The rotating electromagnet is +the <i>armature</i>.</p> + +<p><span class="pagenum">[20]</span></p> + +<h3>WHAT TO DO: Make A Motor</h3> + +<p><i>Tools Needed:</i></p> + +<p>Pocket knife, hammer, vise (or 2 pairs +of pliers).</p> + +<p><i>Materials Needed</i>:</p> + +<pre> +1 roll of No. 24 enameled wire +1 roll of electrician's tape +3 - 4" (20-penny) nails +4 - 2-1/2" (8-penny) nails +4 - 3" brads (10 penny) +Wood board for motor base +2 staples or 4 small brads +2 tacks +2 - 3 volt dry cell batteries (or a 6 +volt transformer). +</pre> + +<h3>Step No. 1-Armature</h3> + +<div class="figcenter"> +<img src="images/p20_step1a.jpg" width="125" height="95" alt="" /> +</div> + +<p>Wrap about 1-1/2" of a +4" nail with two layers of +tape. This will be the +shaft.</p> + +<div class="figcenter"> +<img src="images/p20_step1b.jpg" width="125" height="130" alt="" /> +</div> + +<p>The iron core will be +made of two pairs of +2-1/2" nails. Wrap tape +around each pair with +heads and points alternated.</p> + +<div class="figcenter"> +<img src="images/p20_step1c.jpg" width="125" height="100" alt="" /> +</div> + +<p>Center both pairs on each +side of the shaft. Place +them about 1" from the +head of the shaft nail. +Wrap them together with +two layers of tape from +tip to tip.</p> + +<div class="figcenter"> +<img src="images/p20_step1d.jpg" width="125" height="85" alt="" /> +</div> + +<p>Start at the shaft and wind +No. 24 enameled wire to +one end and back. Then +do the same on the other +end. Always wind in the +same direction. Leave 6" +of spare wire at start and +finish.</p> + +<h3>Step No. 2-Commutator</h3> + +<div class="figcenter"> +<img src="images/p20_step2a.jpg" width="237" height="112" alt="" /> +</div> + +<p>Scrape all insulation off the ends of the wire. +Bend the bare ends back and forth as +shown. Lay them flat over the taped shaft-one +on each side of the shaft.</p> + +<div class="figcenter"> +<img src="images/p20_step2b.jpg" width="137" height="105" alt="" /> +</div> + +<p>Hold the commutator down with narrow +strips of tape. Wrap tightly near the core +and at the opposite end.</p> + +<h3>Step No. 3-Field</h3> + +<div class="figcenter"> +<img src="images/p20_step3a.jpg" width="112" height="95" alt="" /> +</div> + +<p>Make the core by bending +two 4" nails in the middle +at right angles. Space the +heads about 3" apart to +form a horseshoe. Wrap +together with two layers +of tape.</p> + +<div class="figcenter"> +<img src="images/p20_step3b.jpg" width="200" height="153" alt="" /> +</div> + +<p>Wind about 400 turns of wire around the +center. Leave 4" of spare wire at start +and finish. Attach to wood base with staples +at each end of the wire. Small brads, bent +over, will do just as well.</p> + +<p><span class="pagenum">[21]</span></p> + +<h3>Step No. 4—Armature Supports and Brushes</h3> + +<div class="figcenter"> +<img src="images/p21_armature.jpg" width="237" height="182" alt="" /> +</div> + +<p>Scrape the insulation from the ends of two +6" pieces of wire. Tack them to the base +and bend them as shown to make brushes.</p> + +<p>Drive two pairs of 3" brads into the base +about 3-1/4" apart and in a line midway +between the field poles. Wrap wire around +the supports to form armature bearings.</p> + +<p>Scrape insulation off ends of wire from the +field. Connect one end to a brush wire.</p> + +<div class="figcenter"> +<img src="images/p21_assembled.jpg" width="212" height="222" alt="" /> +</div> + +<p><i>Assemble As Shown</i></p> + +<p>Adjust the position of commutator and +tension of brushes against it for best operation.</p> + +<p>Take the armature off the motor and +connect the commutator wires to a dry +cell battery. Test the polarity of each end +of the armature with a compass. Switch +the connections on the commutator and +test again. See how the compass needle +changes direction?</p> + +<p>With the armature still off, connect the +field coil directly to the dry cell. Test the +polarity of each end of the field with the +compass. How can you reverse the polarity? +Try it. It's easy.</p> + +<p>Reassemble the motor again and start +it. Push the field poles slightly out of +alignment with the turning armature. What +happens to the motor's speed? Can you +tell why?</p> + +<p>This time, push the field poles completely +out of the way. Test the polarity of +the armature as you slowly turn it by hand. +Do you see what happens and why it does?</p> + +<p>Try to reverse the direction of rotation +of your motor by reversing the connections +at the battery. What happens? Can you explain +why?</p> + +<h3>Demonstrations You Can Give</h3> + +<p>Make a display board showing the parts +of the toy motor and explain how each part +works compared with the parts of a commercial +motor.</p> + +<h3>For Further Information</h3> + +<p>There are several other types of toy +motors you can build. Your club leader or +power supplier can help you find information +about them.</p> + +<p><span class="pagenum">[22]</span></p> + +<p>1. Did your toy motor run?</p> + +<p>2. Did your motor speed up or slow down when you pushed the field poles out of line?</p> + +<p>Why?</p> + +<p>3. What happens to the magnetic polarity of the armature when you turn it slowly by hand and +check it with a compass?</p> + +<p>4. How can you reverse the direction of rotation of your toy motor?</p> + +<p>Is there another way too?</p> + +<p>What is it?</p> + +<hr class="chapter" /> + +<p><span class="pagenum">[23]</span></p> + +<div> +<img src="images/electprog_logo.jpg" width="50" height="70" alt="" class="split" /> +<img src="images/4h_logo.jpg" width="60" height="60" alt="" class="splitr" /> +</div> + +<h2 id="LESSON_NO_B-6">LESSON NO. B-6</h2> + +<p class="h4">Credit Points 3</p> + +<h3><b>TAKING CARE OF ELECTRIC MOTORS</b></h3> + +<p>Through the magic of electric motors, +much of our work is done faster and +better at lower cost than we could do it +without the help of the electric motor. +People who use motors and treat them properly +have much more time for other work +and for leisure time activities. A 1/4-horsepower +motor running quietly and steadily +hour after hour will do the work of one +man, and operate all day for about 5 cents +without tiring. On many jobs it will work +without "supervision", turning on and off +automatically, as required. It does this on +water pumps, in heating and cooling units, +and on fans and similar appliances.</p> + +<div class="figcenter"> +<img src="images/p23_motors.jpg" width="187" height="167" alt="" /> +</div> + +<p>All that a motor needs to do its work is +electricity and a little care. Let's see what +you can do to give proper care to motors in +your home and on your farm.</p> + +<h3>You'll Need</h3> + +<p>A light oil (SAE 10) for motors of less +than one horsepower and a slightly heavier +oil (SAE 20) for larger motors. See if you +need grease for cups which may be on large +motors. If so, be sure you use ball-bearing +grease and not ordinary cup grease. Cotton +waste or clean rags will be needed for wiping +off the motors, and a tire pump or +vacuum cleaner for blowing out the dust or +dirt.</p> + +<div class="figcenter"> +<img src="images/p23_instrux.jpg" width="135" height="188" alt="" /> +</div> + +<p class="caption">Some motors have instructions for oiling on the name-plate.</p> + +<h3>WHAT TO DO</h3> + +<p>1. First, make a list of all the electric +motors that work for your home. You may +wish to make a separate list for your farm +buildings. You'll probably be surprised at +how many there are. Don't forget the sewing +machine, the refrigerator, the freezer, +the vacuum cleaner and other small but important +motors. Don't touch any motor that +is running. Disconnect them before you +touch them.</p> + +<p>2. Make a motor service chart with +columns headed: Use, Location, Horsepower, +Volts, Amperes, Service Required, +Date Serviced and What was Done. (See +sample) Then list all the motors that require +any servicing. Some will have the instructions +on the motor or appliance; the +instruction booklet that came with the +motor or appliance will also tell what servicing +is required.</p> + +<p><i>Step 1.</i> Plan the job. Start with the +motors in the home. Then you can care for +the motors on the farm.</p> + +<p><span class="pagenum">[24]</span></p> + +<p><i>Step 2.</i> Be sure that any motor on which +you are going to work is disconnected. +Then wipe the outside case clean with a +cloth. If the motor has openings in the end, +use a vacuum cleaner to suck out dust, dirt +or chaff. A tire pump may also be used to +blow out this dirt. If you use compressed +air, be sure the pressure is not high as it +may damage wiring inside the motor. Dust-proof +motors should be used in dusty or +dirty places.</p> + +<p><i>Step 3.</i></p> + +<div class="figcenter"> +<img src="images/p24_step3.jpg" width="175" height="125" alt="" /> +</div> + +<p class="caption">If there are oil holes, oil according to the manufacturer's instructions.</p> + +<p>If there are no instructions, remember +a little oil goes a long way as far as motors +are concerned. Motors of less than one +horsepower require only 3 or 4 drops (not +squirts) of oil every 3 or 4 months if the +motor is used frequently. Too much oil +can damage the motor. It spoils the insulation.</p> + +<p>If there are no oil holes or grease cups +on the motor, it is probably lubricated by +means of grease sealed in the bearings at +the factory, or it may use greaseless bearings, +and does not need to be oiled or +greased periodically. Indicate on your +chart all motors which need periodic care +and see that it is given according to +schedule.</p> + +<p>Wipe away any excess oil or grease. Be +sure oil holes are capped or covered.</p> + +<p><i>Step 4.</i> Reconnect motor and run for a +moment.</p> + +<p><i>Step 5.</i> Record on the chart the date you +serviced the motor and what was done.</p> + +<h3>What Did You Learn?</h3> + +<p>How many motors are there in your home? +______ On the farm? ______</p> + +<p>How many motors need regular oiling or +grease? ______</p> + +<p>How many are less than one-horsepower? ______</p> + +<p>SAE Oil ______ is used to oil motors up to +1/2 horsepower. How much oil?______</p> + +<p>SAE Oil______ is used for larger motors.</p> + +<h3>Demonstrations You Can Give</h3> + +<p>1. Show how to clean a small motor.</p> + +<p>2. Explain proper lubrication of motors.</p> + +<p>3. Using the chart prepared in this work +sheet, give a talk about the motors that +work for you-the job each one does, +which ones need oil or grease, which +need no attention, and why, etc.</p> + +<p>4. Use a homemade toy motor to explain +"what makes motors run."</p> + +<p>5. Show proper way to replace worn cord +on a small motor.</p> + +<h3>For Further Information</h3> + +<p>Ask your county Extension agent or 4-H +leader for more literature on motors. They +can help you obtain a film or a speaker +such as a power supplier, a local electric +dealer, or electrical contractor to discuss +motors.</p> + +<p>Also visit your public library and see a +science teacher for more information on +motors.</p> + +<p><span class="pagenum">[25]</span></p> + +<p class="spacer"> </p> + +<h3>ELECTRIC MOTORS SERVICE CHART Sample</h3> + +<p class="h5">Use a table like the following to list the motors around your farm and home.</p> + +<div class="center"> +<table border="2" cellpadding="10" cellspacing="0" summary="Motor Service Table"> + <tr> + <td class="tdl">Motor Use</td> + <td class="tdl">Location</td> + <td class="tdl">H.P.</td> + <td class="tdl">Volts</td> + <td class="tdl">Amps.</td> + <td class="tdl">Service Needed</td> + <td class="tdl">Date Serviced and what was done</td> + </tr> + <tr> + <td class="tdl">Food Mixer</td> + <td class="tdl">Kitchen</td> + <td class="tdl">1/6</td> + <td class="tdl">120</td> + <td class="tdl">4.4</td> + <td class="tdl">Clean & Oil; cord needs repair</td> + <td class="tdl">9/1-Cleaned w/cloth. Oiled w/#10 Oil; repaired cord</td> + </tr> + <tr> + <td class="tdl">Tool Grinder</td> + <td class="tdl">Farm Shop</td> + <td class="tdl">1/4</td> + <td class="tdl">120</td> + <td class="tdl">5.8</td> + <td class="tdl">Clear, oiling; Have switch repaired</td> + <td class="tdl">10/6-Cleaned w/vacuum; Oiled, #10 oil. 10/20. Had switch repaired</td> + </tr> + <tr> + <td class="tdl">Pump</td> + <td class="tdl">Pump house</td> + <td class="tdl">1/3</td> + <td class="tdl">120</td> + <td class="tdl">7.2</td> + <td class="tdl">Oiling, cleaning</td> + <td class="tdl">9/26-Cleaned w/tire pump; oiled w/10 oil</td> + </tr> + <tr> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + </tr> + <tr> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + </tr> + <tr> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + </tr> + <tr> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + </tr> +</table></div> + +<hr class="chapter" /> + +<p><span class="pagenum">[26]</span></p> + +<div> +<img src="images/electprog_logo.jpg" width="50" height="70" alt="" class="split" /> +<img src="images/4h_logo.jpg" width="60" height="60" alt="" class="splitr" /> +</div> + +<h2 id="LESSON_NO_B-7">LESSON NO. B-7</h2> + +<p class="h4">Credit Points 4</p> + +<h3>READING THE ELECTRIC METER</h3> + +<p>There is no question but what electricity +is one of the lowest cost services in +the home and on the farm. A few pennies +worth of electricity will provide the power to +run machines that take the place of a man or +of several men working all day. However, we +all like to know what things cost.</p> + +<p>Sometime you may have to decide between +different methods—man, horse, gasoline engine +or electric motor power. Then you'll +want to know how to figure the cost of electricity, +as well as the cost of the original +equipment. First of all, you should know +how to read an electric meter.</p> + +<h3>Reading a Meter</h3> + +<p>Electric meters read in kilowatt hours, just +as a water meter reads in gallons and a gas +meter in cubic feet. A kilowatt hour is the +electrical energy consumed by 1000 watts of +electricity used for one hour. Ten 100-watt +light bulbs burning for one hour would use +one kilowatt-hour—one kwh.</p> + +<div class="figcenter"> +<img src="images/p26_fig1.jpg" width="175" height="98" alt="" /> +</div> + +<p class="caption">Figure 1. Some meters give the reading directly, like the mileage total on a speedometer.</p> + +<p>Some meters are read directly, as shown +in Figure 1. The more common type has four +dials which are read from right to left—just +the opposite from the way things are usually +read. The hand on the extreme right turns +clockwise, the next hand turns counter-clockwise, +the next clockwise; the last hand on +the left turns counter-clockwise.</p> + +<div class="figcenter"> +<img src="images/p26_readingmeter.jpg" width="212" height="180" alt="" /> +</div> + +<p>The first dial on the right can register +up to 10 kilowatt-hours; the second up to 100 +kwh; the third, to 1000 kwh; the fourth, to +10,000 kwh. After that, the meter starts over +again. To take a reading you must read all +four dials of the meter, from right to left.</p> + +<div class="figcenter"> +<img src="images/p26_fig2.jpg" width="237" height="127" alt="" /> +</div> + +<p class="caption">Figure 2. Meter dials are read from right to left.</p> + +<p>To read each dial, you use the number +last passed by the dial hand. This may not be +nearest the hand. For instance, if the pointer +has passed 6 and is almost on 7, you read it +as 6. Write down the figures in the same +order you read the dial, from right to left. +Practice reading the meters shown in Figure +3 on the following page.</p> + +<h3>What's Your Electric Bill?</h3> + +<p>Meters aren't set back each month when +the meter reader comes around. The difference<span class="pagenum">[27]</span> +in the readings from one month to the +next shows how many kilowatt-hours have +been used. If you know your electric rates, +you can figure your bill by yourself. Your +power supplier will furnish you with a rate +schedule on request.</p> + +<div class="figcenter"> +<img src="images/p27_fig3.jpg" width="250" height="247" alt="" /> +</div> + +<p class="caption">Figure 3. See if you can read the above correctly. The answers are shown in a box on the next page.</p> + +<p>It will be interesting to you to find out +how much it costs to operate the various +electric appliances in your home. A sample +rate schedule is shown in Figure 4.</p> + +<div class="figcenter"> +<img src="images/p27_fig4.jpg" width="225" height="167" alt="" /> +</div> + +<p class="caption">Figure 4. Sample rate schedule. Note that as the use of electricity increases, the average cost per kwh is reduced.</p> + +<h3>Estimating Operating Costs</h3> + +<p>To find the cost of operating any single +appliance, three steps are necessary:</p> + +<p>1. Learn the wattage of the appliance.</p> + +<p>2. Estimate how many hours the appliance +is used.</p> + +<p>3. Find its operating cost.</p> + +<p><i>To Find Wattage:</i></p> + +<p>Watts, you know, are the measure of +electrical power. They are the product of +voltage (pressure) times amperes (rate of +flow). Volts times Amps equals Watts. The +nameplate on the appliance will give the voltage +required for proper operation as well as +either amperage or watts. If it gives wattage, +you have the information you want. Otherwise +you must multiply volts times amps to +get the wattage. When voltage is given as +110-120, use 120 as your voltage. 120 volts +is nominal today.</p> + +<p><i>How Much Will You Use?</i></p> + +<p>Now that you know the wattage of the appliance, +multiply this figure by number of +hours the equipment operates in one day. +Divide this by 1000 to get the kwh. Now multiply +the result by the number of days the +appliance is used each month. This tells you +the number of kwh used by the appliance during +the month.</p> + +<div class="inset26 topbox"> +<p class="h5">Example No. 1</p> +<p class="margin20"><i>Yard Light:</i> 300-watt lamp<br /> +<br /> +Amount of use: 3 hours per night.<br /> +<br /> +Multiply lamp wattage times hours of use +per night to get watt-hours per night.<br /> +<br /> +300 times 3 = 900 watt-hours per night.<br /> +<br /> +Divide watt-hours by 1000 to get kwh per night.<br /> +<br /> +900 divided by 1000 = .9 kwh per night.<br /> +<br /> +Multiply kwh per night times 30 to get kwh per month.<br /> +<br /> +.9 times 30 = 27 kwh per month.<br /> +<br /> +If the yard light is used 3 hours per night, it consumes 27 kwh per month. +</p> +</div> + +<p><span class="pagenum">[28]</span></p> + +<p class="spacer"> </p> + +<div class="inset26 topbox"> +<p class="h5">Example No. 2</p> + +<p class="margin20"><i>Coffee Maker</i>: 120 volts, 550 watts (from nameplate)<br /> +<br /> +Amount of use: 1/2 hour per day.<br /> +<br /> +Multiply wattage of coffee maker times +hours of use per day to get watt-hours per day.<br /> +<br /> +550 times 1/2 hour = 275 watt-hours per day.<br /> +<br /> +Divide watt-hours by 1000 to get kwh per day.<br /> +<br /> +275 divided by 1000 = .275 kwh per day.<br /> +<br /> +Multiply kwh per day times 30 to get kwh per month.<br /> +<br /> +.275 times 30 = 7.250 kwh per month.<br /> +<br /> +If the coffee maker is used l/2 hour daily, +it consumes 7.25 kwh per month. +</p> +</div> + +<p><i>Calculate Operating Cost Per Month</i></p> + +<p>Now that you know the number of kilowatt +hours an appliance uses, go to your rate +schedule and your electric bill to see what the +average kwh costs. Find the average cost of +1 kwh by dividing the amount of your bill by +the total number of kwh used in a month.</p> + +<p class="hang"> +<i>Example</i>: 410 kwh used.<br /> +$14.35 total monthly bill<br /> +<br /> +Average cost per kwh equals $14.35 divided +by 410 kwh-3-1/2 cents per kwh.</p> + +<p>Therefore, the cost of operating the coffee +maker for a month would be 3-1/2 cents +times 7.25 kwh—25.4 or 25 cents. Cost of +operating the yard light would have been 94.5 +or 95 cents a month.</p> + +<div class="inset20 topbox"> +<p class="margin20">(a) 6357 nbsp; (b) 1963 (c) 8996 +<br /><br /> +Correct answers to the meter readings +shown on the preceding page. +</p> +</div> + +<h3>Adding Low Cost Helpers</h3> + +<p>You can see, by looking at your rate schedule, +that the average cost per kwh gets lower +as you use more electricity. To find the +cost of operating additional electrical equipment, +the cost per kilowatt hour is found from +the last "step" in the bill—the lowest cost +per kwh of the electricity you're now using. +Sometimes power suppliers give special rates +for such equipment as electric water heaters.</p> + +<h3>WHAT TO DO: Find the Cost +of Operating Electrical Equipment</h3> + +<p>Make and fill in the blanks of a chart +showing the electrical equipment you have +and the operating costs per month.</p> + +<p>Make a chart for the home (refer to chart +one). Show the probable operating cost of +equipment you might add to what you now +have.</p> + +<h3>Demonstrations You Can Give</h3> + +<p>Show how to read a meter, making one +with plywood or cardboard. Dials can be +painted on the main board. Arrows can be +attached so they will revolve to give different +readings.</p> + +<p>Show how to find the wattage of various +types of equipment.</p> + +<p>Show how to figure the cost of the average +kwh in a home.</p> + +<h3>For Further Information</h3> + +<p>Your leader can get additional material +for you or you may want to have someone +from your power supplier talk to your club, +telling about meters, how they work and how +they are regularly checked for accuracy.</p> + +<p><span class="pagenum">[29]</span></p> + +<p class="h4">Chart One-THE HOME</p> + +<div class="center"> +<table border="2" cellpadding="10" cellspacing="0" summary="Home Wattage Chart"> + <tr> + <td class="tdc">Column No.</td> + <td class="tdc">1.</td> + <td class="tdc">2.</td> + <td class="tdc">3.</td> + <td class="tdc">4.</td> + <td class="tdc"> </td> + </tr> + <tr> + <td class="tdl">Item</td> + <td class="tdl">Wattage Rating</td> + <td class="tdl">Hours Used per Month</td> + <td class="tdl">KWH per Month<br />(col. 1 x 2) / (1000)</td> + <td class="tdl">Cost per Month<br />(Col. 3 x av.kwh cost)</td> + <td class="tdl">Remarks</td> + </tr> + <tr> + <td class="tdl">Electric Iron</td> + <td class="tdl">1100</td> + <td class="tdl">30</td> + <td class="tdl">33</td> + <td class="tdl">.80</td> + <td class="tdl"> </td> + </tr> + <tr> + <td class="tdl">Stove</td> + <td class="tdl">880</td> + <td class="tdl">60</td> + <td class="tdl">52.8</td> + <td class="tdl">1.21</td> + <td class="tdl">(Special rate.)</td> + </tr> + <tr> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + </tr> + <tr> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + </tr> + <tr> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + </tr> + <tr> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + </tr> + <tr> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + <td class="tdl"> </td> + </tr> +</table></div> + +<hr class="chapter" /> + +<p><span class="pagenum">[30]</span></p> + +<div> +<img src="images/electprog_logo.jpg" width="50" height="70" alt="" class="split" /> +<img src="images/4h_logo.jpg" width="60" height="60" alt="" class="splitr" /> +</div> + +<h2 id="LESSON_NO_B-8">LESSON NO. B-8</h2> + +<p class="h4">Credit Points 3</p> + +<h3><b>IRONING IS FUN WITH THE MODERN HAND IRON</b></h3> + +<p>When you are getting ready to go to +school or to a party, it probably gives +you a good feeling to put on a clean, +freshly-ironed skirt, blouse or dress. But +did you ever think about the electric iron +that helps so much to give you that well-dressed +feeling? When you were younger, +you may have had a play iron and pretended +to iron your doll's dresses. Now +you are old enough to learn about real +irons—the different kinds of irons, how +the iron heats, the kind of cord needed, the +type of outlet necessary, how to use safety +rules when you iron, and even how to help +with the ironing.</p> + +<div class="figcenter"> +<img src="images/p30_ironing.jpg" width="172" height="249" alt="" /> +</div> + +<h3>Important Things to Know</h3> + +<p>There are many different irons, but the +two kinds most important for you to know +about now are the regular dry iron and the +combination steam-and-dry iron.</p> + +<div class="figcenter"> +<img src="images/p30_thermostat.jpg" width="237" height="79" alt="" /> +</div> + +<p class="caption">The thermostat keeps the iron at an even temperature.</p> + +<p>It isn't weight alone that makes an iron +do its job, but the heat of the iron. The heat +is given off in the sole plate. The automatic +iron has what is called a <i>thermostatic</i> control +which holds the temperature of the +iron at the heat you want. Some clothes +need to be ironed with a very hot iron, +while others need only to be pressed lightly +with a cool iron. The thermostat keeps +the iron at an even temperature after you +set it for the heat you want. The thermostat +is the heart of the iron.</p> + +<p>Take a look at the iron used in your +home. It isn't heavy to lift, and has a +handle that fits your hand easily. It looks +graceful and has a smooth bottom, called +the sole plate. And it may have a narrow, +pointed tip which is helpful in ironing pleats, +corners and gathers.</p> + +<div class="figcenter"> +<img src="images/p30_soleplate.jpg" width="175" height="165" alt="" /> +</div> + +<p class="caption">Your iron has a smooth bottom called the sole plate.</p> + +<p><span class="pagenum">[31]</span></p> + +<h3>The Iron and Safety</h3> + +<p>If you are going to learn to do some +ironing yourself, the most important thing +for you to remember is SAFETY. You +should read all about the iron first in the +instructions which came with it.</p> + +<p>Never use an iron carelessly. Remember +the safety rules:</p> + +<p>1. An iron should never be left even for +a few minutes without being disconnected. +Turn off by removing the plug from the outlet, +or by turning the control lever to "off."</p> + +<div class="figcenter"> +<img src="images/p31_plug.jpg" width="130" height="110" alt="" /> +</div> + +<p class="caption">Take hold of the plug—not the cord—when you disconnect +it from the outlet.</p> + +<p>2. Let the iron cool before putting it +away.</p> + +<p>3. Wrap the cord carefully around the +iron after it is cold.</p> + +<p>4. Always stand the iron where it will +not fall off on a child or pet or your own +toes.</p> + +<h3>WHAT TO DO: Learn About Your Iron</h3> + +<p>Materials Needed: An automatic iron, some +old play clothes, towels, napkins or handkerchiefs, +and an ironing board.</p> + +<p>Steps to Take:</p> + +<p>1. Watch an experienced person iron.</p> + +<p>2. Ask questions about what clothes +need to be sprinkled.</p> + +<p>3. Study the thermostat settings on the +dial or indicator.</p> + +<div class="figcenter"> +<img src="images/p31_dial.jpg" width="133" height="110" alt="" /> +</div> + +<p class="caption">Most irons have a dial to set for the proper heat for different fabrics.</p> + +<p>4. Ask about the kind of fabric each piece +of clothing is—cotton, linen, silk, nylon, +etc.—and why the iron should be at high +heat for some, cooler for others.</p> + +<p>5. Set the thermostat for the amount of +heat needed, and with an older person +watching you, iron some handkerchiefs, +napkins, bath towels, and a pair of play +shorts or blue jeans.</p> + +<p>6. During a month iron some of these +articles for your family, keeping a record +of how many you do and what they were.</p> + +<p>7. Take care of your iron. Be responsible +for storing it.</p> + +<div class="center"> +<table border="2" cellpadding="3" cellspacing="0" summary="Ironing Log"> +<tr><td class="tdc">Date</td><td class="tdc">No. Aricles Ironed</td><td class="tdc">Type of Article</td><td class="tdc">Stored Iron Properly<br />(check)</td></tr> +<tr><td class="tdc"> </td><td class="tdc"> </td><td class="tdc"> </td><td class="tdc"> </td></tr> +<tr><td class="tdc"> </td><td class="tdc"> </td><td class="tdc"> </td><td class="tdc"> </td></tr> +<tr><td class="tdc"> </td><td class="tdc"> </td><td class="tdc"> </td><td class="tdc"> </td></tr> +<tr><td class="tdc"> </td><td class="tdc"> </td><td class="tdc"> </td><td class="tdc"> </td></tr> +<tr><td class="tdc"> </td><td class="tdc"> </td><td class="tdc"> </td><td class="tdc"> </td></tr> +</table></div> + +<p class="spacer"> </p> + +<p><span class="pagenum">[32]</span></p> + +<h3>IRONING IS FUN</h3> + +<p>1. I (use) (do not use) an adjustable ironing Board at home. If I do, I adjust it to the height +that just clears my knees easily as I sit in a comfortable chair. Yes No</p> + +<p>2. There are three kinds of irons usually used—dry iron, steam iron or a combination steam +or dry iron. I use a —— iron.</p> + +<p>3. I (have) (do not have) the instruction book. (If you do, read about the iron.) I know the +iron's parts by their correct names. They are——.</p> + +<p>4. I disconnect the iron if I leave it even for only a minute. This is a safety measure as fires +have been known to start from irons left connected. Yes No</p> + +<p>5. I take hold of the plug—not the cord—when disconnecting the iron. Yes No</p> + +<p>6. I wait until the iron is cold before wrapping the cord around the handle and storing the iron +because——.</p> + +<p>7. Most irons have a thermostatic control. The iron I am using has settings for——.</p> + +<p>8. The purpose of the thermostat is——.</p> + +<p>9. These fabrics need high temperature.——</p> + +<p>These fabrics need medium temperature.——</p> + +<p>These fabrics need low temperature.——</p> + +<p>10. These fabrics need sprinkling.——</p> + +<p>11. The heat and smoothness of the sole plate smoothes the wrinkles. Pushing down on the +handle or moving the iron rapidly only makes ironing hard work. I will iron slowly and +steadily arranging and moving the garment with the left hand while guiding the iron with +the right hand. (Or the other way for the left handed.) Yes No</p> + +<p>12. I have watched an experienced person iron. Yes No</p> + +<p>13. I have practiced on handkerchiefs, napkins and pillow cases.</p> + +<p>14. Here is my record of ironing for one month</p> + +<p><span class="pagenum">[33]</span></p> + +<div class="inset26 topbox"> +<p> +<br /> +<br />Month____________</p> + +<p class="right">Your Name _____________________</p> +<br /> +<p>Date I have ironed:<br /> +_____________________________________________________<br /> + | <br /> + | <br /> + | <br /> + | <br /> + | <br /> + | <br /> + | <br /> + | <br /> +</p> +</div> + +<p><span class="pagenum">[34]</span></p> + +<p class="spacer"> </p> + +<h3>Demonstrations You Can Give</h3> + +<p>1. Show a dry iron and a steam-and-dry +iron. Tell the difference between them and +when each is to be used.</p> + +<p>2. Display garments that look nice because +they have been ironed properly, and +those that have been ironed improperly. +Explain about the heat, thermostat, type of +iron and why results differ.</p> + +<h3>For More Information</h3> + +<p>At a club meeting ask a parent to give a +demonstration of ironing different articles. +Some power suppliers or dealers have +people who will demonstrate the proper way +to iron, and how to care for irons.</p> + +<hr class="chapter" /> + +<p><span class="pagenum">[35]</span></p> + +<div> +<img src="images/electprog_logo.jpg" width="50" height="70" alt="" class="split" /> +<img src="images/4h_logo.jpg" width="60" height="60" alt="" class="splitr" /> +</div> + +<h2 id="LESSON_NO_B-9">LESSON NO. B-9</h2> + +<p class="h4">Credit Points 2</p> + +<p class="h3"><b>LET'S BE FRIENDS WITH ELECTRICITY +Plan a Hazard Hunt</b></p> + +<p>Electricity can be your important lifelong +friend and helper, so you will want to +know all you can about it and how to treat it +properly. However, careless and improper +use of electricity can do a lot of harm. Used +properly, and treated with respect, electricity +can do wonderful things to help you every +day in many ways.</p> + +<p>For safe and proper use of electricity, +all wiring, fittings, insulation, cords and +plugs must be in good condition. You can be +a detective and track down defects in any +such type of electrical equipment that you +may be using in your home or on your farm.</p> + +<p>When you find anything that is wrong, and +know where it is, and know what to do about +it, you can very likely correct the condition +yourself, such as replacing a worn extension +cord with a new one. If you find defects in +permanent wiring, or some places where +wires are bare or terminals are needed, you +should tell your parents about them.</p> + +<p>SAFETY FIRST, remember, should always +be on your mind when working with +anything electrical.</p> + +<h3>WHAT TO DO:</h3> + +<p><i>1. Have A Hazard Hunt</i></p> + +<p>Go on a Hazard Hunt to see how many +electrical hazards you can find. Look for +defects such as broken insulation, worn +cords, splices that are not properly soldered +and taped, loose connections, or switches +that aren't working properly.</p> + +<p>There are many ways to have a Hazard +Hunt. Choose the method that will be the +most fun. Use the Hazard Hunt Guide in this +outline to check your home, and other buildings. +Maybe you'll want to have a friend help +check your home, then you help him check +his. Or, why not give each member of your +family a Hazard Hunt Guide and have a contest? +Parents may want to team up against +you and other younger members of your +family to see which team can find the most +electrical hazards in some set time—say 30 +minutes.</p> + +<p>Have a Hazard Hunt Committee in your +club check all member's homes and buildings +and report its findings at the next club +meeting.</p> + +<p><i>To Make It More Fun</i></p> + +<p>1. Put a hazard tag, like the one shown, +(Figure 1) by each hazard that is found. +Leave it until the hazard is corrected. +Have another contest to see which member +of the family corrects the most +hazards.</p> + +<div class="figcenter"> +<img src="images/p35_fig1.jpg" width="127" height="162" alt="" /> +</div> + +<p class="caption">Figure 1</p> + +<p>2. Report on your Hazard Hunt at the next +club meeting. Tell about the Hazards +found, and what you have done or plan to +do about them.</p> + +<p>3. Suggest that the entire club have an Electric +Hazard Hunt at your club meeting +places or any community building. This +could be part of one meeting.</p> + +<p><span class="pagenum">[36]</span></p> + +<p>4. Have a contest between two teams in the +club to see which team can get the most +homes in your community checked by the +Hazard Hunt Guide. Losers could give a +party for the winners.</p> + +<p><i>2. Get Others Interested</i></p> + +<p>Promote a community Electric Hazard +Hunt. Enlist the support of power suppliers, +electric supply and equipment dealers, +schools, newspapers, radio and television +stations.</p> + +<p><i>What To Look For</i></p> + +<p>Make a complete tour of your home and +other buildings and see how many hazards +you can locate. When you find a hazard, put +a tag near it to mark it.</p> + +<div class="inset20 topbox"> +<h3>SAFETY TIPS</h3> + +<p class="margin20">Put hazard tags <i>near</i> the hazard +but <i>not</i> directly on broken or frayed +wires, insulators, fittings, or other +wiring equipment. Do not touch them +either. Badly-frayed wires should be +disconnected immediately from the +power supply. In this way, you will +not expose yourself to shock by accidentally +touching an exposed live +wire that may be carrying current.</p> +</div> + +<h3>4-H Electric Hazard Hunt Guide</h3> + +<p><i>Wiring and Protective Devices</i></p> + +<p>1. Cable or conduit splices not +in boxes——</p> + +<p>2. Cable or conduit not securely +clamped in boxes——</p> + +<p>3. Conduit or armored cable not +properly grounded——</p> + +<p>4. Cracked or broken insulators +(Figure 2)——</p> + +<p>5. Wire not completely covered +with insulation——</p> + +<p>6. Worn insulation on wire——</p> + +<div class="figcenter"> +<img src="images/p36_fig2.jpg" width="115" height="183" alt="" /> +</div> + +<p class="caption">Figure 2</p> + +<p>7. Old unused wiring not yet +removed——</p> + +<p>8. Outlets, junction and switch +boxes not securely fastened +and covers not in place——</p> + +<p>9. Switches not working properly +(sparks fly as switch is flipped) +(Figure 3)——</p> + +<p>10. Fuses not of proper ampere +rating for circuit——</p> + +<p>11. Extension cord used in place +of permanent wiring——</p> + +<p>12. Pull chain socket without an +insulating link in the chain——</p> + +<p>13. Pull chain socket near plumbing +fixtures or where hands +may be wet or one may stand +in water——</p> + +<div class="figcenter"> +<img src="images/p36_fig3.jpg" width="145" height="205" alt="" /> +</div> + +<p class="caption">Figure 3</p> + +<p><span class="pagenum">[37]</span></p> + +<p>14. No moisture-proof cords for +outside weather conditions or +heavy rubber cords for +motors and motor driven +appliances</p> + +<p><i>Lighting</i></p> + +<p>1. Fixtures in farm buildings +installed so that they might +be easily damaged</p> + +<p>2. Lights in haymows and other +dusty locations not protected +by dustproof globes</p> + +<p>3. Outside sockets not waterproof</p> + +<p>4. Heat lamps not properly supported +by non-current carrying +wire, chains, or brackets +(Figure 4)</p> + +<p>5. Light bulbs not frosted, +shaded, or placed so that light +is diffused to prevent glare</p> + +<div class="figcenter"> +<img src="images/p37_fig4.jpg" width="177" height="187" alt="" /> +</div> + +<p class="caption">Figure 4</p> + +<p><i>Auxiliary Wiring</i></p> + +<p>1. Outlets overloaded—in other +words, "octopus wiring"</p> + +<p>2. Extension cords placed under +rugs</p> + +<p>3. Extension cords run through +doorways (Figure 5)</p> + +<div class="figcenter"> +<img src="images/p37_fig5.jpg" width="185" height="155" alt="" /> +</div> + +<p class="caption">Figure 5</p> + +<p>4. Extension cords or lamp +cords should use underwriters' +knot (Figure 6)</p> + +<div class="figcenter"> +<img src="images/p37_fig6.jpg" width="165" height="113" alt="" /> +</div> + +<p class="caption">Figure 6</p> + +<p>5. Plug connections fuzzy (Figure +7)</p> + +<div class="figcenter"> +<img src="images/p37_fig7.jpg" width="172" height="112" alt="" /> +</div> + +<p class="caption">Figure 7</p> + +<p>6. Extension cords run over +heaters or radiators</p> + +<p>7. Extension cords, or appliance +or lamp cords, worn or frayed</p> + +<p>8. Heating appliances without +regular asbestos covered +wire</p> + +<p>9. Open sockets or outlets +where a baby or small child +might stick a finger or metal +toy</p> + +<p><span class="pagenum">[38]</span></p> + +<p>10. Broken plugs (Figure 8)——</p> + +<p>11. Loose prongs on appliance +or lamps plugs——</p> + +<div class="figcenter"> +<img src="images/p38_fig8.jpg" width="165" height="113" alt="" /> +</div> + +<p class="caption">Figure 8</p> + +<h3>How Many Hazards Did You Find?</h3> + +<p>Make a chart listing the hazards, their +locations and what you did about them. Make +your own chart and list what you find.</p> + +<h3>Demonstrations You Can Give</h3> + +<p>Show and tell others how to have a Hazard +Hunt.</p> + +<h3>For Further Information</h3> + +<p>Check with your leader, then ask your +power supplier or a local electrician to tell +you about safe electrical wiring, connections +and fixtures.</p> + +<div class="center"> +<table border="2" cellpadding="6" cellspacing="0" summary="Hazard Chart"> + <tr> + <td class="tdc">Hazard</td> + <td class="tdc">Location</td> + <td class="tdc">What I Did</td> + </tr> + <tr> + <td class="tdli">Loose prong on lamp plug</td> + <td class="tdli">Living Room</td> + <td class="tdli">Replaced with new plug</td> + </tr> + <tr> + <td class="tdli">Cracked insultor on service wire in house</td> + <td class="tdli">Back of house</td> + <td class="tdli">Notified power supplier</td> + </tr> + <tr> + <td class="tdli">Conduit not securely clamped to box</td> + <td class="tdli">Basement by fuse box</td> + <td class="tdli">Notified parents</td> + </tr> + <tr> + <td class="tdli">Extension cord, old and worn</td> + <td class="tdli">Basement, by washing machine</td> + <td class="tdli">Replaced with new rubber-covered one and protected it from water</td> + </tr> +</table></div> + +<hr class="chapter" /> + +<p><span class="pagenum">[39]</span></p> + +<div> +<img src="images/electprog_logo.jpg" width="50" height="70" alt="" class="split" /> +<img src="images/4h_logo.jpg" width="60" height="60" alt="" class="splitr" /> +</div> + +<h2 id="LESSON_NO_B-10">LESSON NO. B-10</h2> + +<p class="h4">Credit Points 3</p> + +<h3>HOW ELECTRIC BELLS WORK—FOR YOU</h3> + +<div class="figcenter"> +<img src="images/p39_phonecall.jpg" width="300" height="163" alt="" /> +</div> + +<p>When was the last time you wanted to get +a simple message like "You're wanted +on the telephone," "There's someone here to +see you, "or "There's a car in the driveway," +to someone around your place? Did you have +to walk or run some distance and perhaps +shout, too, to be heard by the other person? +Perhaps you had to stop some other work, or +interrupt your favorite kind of fun, to do this +bit of messenger work.</p> + +<p>If the nature of the message is like one of +those mentioned, and the number of people +in hearing is not too great, then perhaps you +can use bells or buzzers or both to do some +of your messenger work for you. Even +though a bell or a buzzer can't talk, it can +convey a message.</p> + +<h3>What to Do</h3> + +<p>1. Learn how bells and buzzers work, +and learn about the many different kinds.</p> + +<p>2. Plan and install a bell system for your +home or farm.</p> + +<h3>Bells and Buzzers Can Tell a Lot</h3> + +<p>Electric bells and buzzers use the same +basic principle as the telegraph system, invented +by Samuel Morse in 1840. Although +not as important today as it was before radio, +telephone, and teletype became common, the +telegraph is still in use.</p> + +<p>Bells and buzzers, however, are very common +and have many uses. They are most +often seen in the form of doorbells, and rare +is the new home that does not have one or +more. Service stations have bell systems to +let the operator know that a car is waiting at +the gas pumps. A clock signal reminds the +homemaker when the cooking time is completed. +Children are called to and released +from school classes by means of bells and +buzzers.</p> + +<p>Also, various alarms employing bells and +buzzers warn us when it's time to get up, or +even that the place is on fire, or that a burglar +is trying to break in!</p> + +<p>Let's find out how bells and buzzers work, +what different kinds there are, the different +ways you can control them, and how you can +put them to work for you.</p> + +<p>You'll find that buzzers and bells can help +you with your 4-H projects, and with the +proper controls, can be your eyes and voice +in a dozen places at once.</p> + +<p><span class="pagenum">[40]</span></p> + +<h3>Why They Buzz or Ring—Electromagnetism</h3> + +<p>If we were to look at an electric bell with +the cover off, we'd find that it would be very +much like Figure 1.</p> + +<p>A push on the button, which is just a switch +that is normally held "open" or off by means +of a spring, sends the current from the battery +or transformer through the circuit.</p> + +<div class="figcenter"> +<img src="images/p40_fig1.jpg" width="170" height="238" alt="" /> +</div> + +<p class="caption">Figure 1</p> + +<p>You will see that the current passes first +through two small coils of wire, and each +coil has at its center a piece of soft iron +called the core. When the current is on, the +core becomes magnetized and attracts another +piece of iron called the armature with its +clapper attached.</p> + +<p>This action rings the bell, but it also breaks +the current by pulling the spring away from +the screw on its return to the power supply.</p> + +<p>With the power off, the electromagnet lets +the spring return the armature to its normal +position, contact is made again, and the +cycle starts all over again—just as long as +you continue to push on the button.</p> + +<p>Buzzers work exactly the same way, except +that they do not have a bell and depend +instead on the vibration of the armature for +a noise that's not as loud or as musical.</p> + +<p>Gongs or chimes, that strike only once +when the button is pushed, are made by connecting +the armature with the screw by means +of a flexible wire.</p> + +<h3>A Special Kind of Electricity</h3> + +<p>Most buzzers and bells work on a much +lower voltage than you normally find in the +wires in your house. Some are made to work +at 6 volts, others at 10 volts, and still others +at slightly higher voltages.</p> + +<p>You can get these low voltages by using one +or more batteries, or by using a transformer +connected to your house current. Most bells +and buzzers are now powered through transformers.</p> + +<h3>How to Control Them</h3> + +<p>The push button is the most common means +of control. You can use one button to control +several bells, or several buttons to control +one bell, or have several buttons control +several bells. Because low voltage is used, +adding extra buttons is simple, inexpensive, +and safe.</p> + +<p>Buzzers and bells can also be controlled +by: <i>clocks</i>, as in the interval timer on an +electric range or in a school class bell system; +<i>temperature detectors</i>, as in a fire +alarm or freezer alarm; <i>door and window +trips</i>, as in a one-man repair shop or in a +burglar alarm; and <i>treadles</i>, as in the driveway +of a service station.</p> + +<div class="figcenter"> +<img src="images/p40_fig2.jpg" width="237" height="217" alt="" /> +</div> + +<p class="caption">Figure 2</p> + +<p><span class="pagenum">[41]</span></p> + +<h3>Pick the Right Bell or Buzzer</h3> + +<p>Some of the many different types of bells, +and various ways of controlling them are +suggested in the table below. Just remember +that no matter what the job or conditions, +you can probably find a bell or buzzer and +controls that suit your need.</p> + +<p class="spacer"> </p> + +<div class="center"> +<table border="2" cellpadding="10" cellspacing="0" summary="buzzer jobs"> + <tr> + <th colspan="5">SOME TYPICAL JOBS FOR BELLS & BUZZERS</th> + </tr> + <tr> + <td class="tdl">Job</td> + <td class="tdl">Type of bell or buzzer</td> + <td class="tdl">Number and location of bells and buzzers</td> + <td class="tdl">Type of control</td> + <td class="tdl">Number and location of controls</td> + </tr> + <tr> + <td class="tdl">Summon others to the telephone</td> + <td class="tdl">In the house— small to medium buzzers<br /> + In outbuildings— medium to large bells<br /> + Outdoors— large weatherproof bell<br /> + All transformer-powered</td> + <td class="tdl">Enough to cover all usual work locations</td> + <td class="tdl">Push-buttons</td> + <td class="tdl">One at the telephone and each extension phone</td> + </tr> + <tr> + <td class="tdl">Notify club member that car is at his produce stand</td> + <td class="tdl">Medium to large bell— transformer-powered</td> + <td class="tdl">One may be enough—if mounted on the back of the stand</td> + <td class="tdl">Hose diaphragm<br /> + (Complete driveway units including control, are available, ready to plug in.)</td> + <td class="tdl">One—in the driveway</td> + </tr> + <tr> + <td class="tdl">Warn of power failure to incubator or brooder</td> + <td class="tdl">Battery-powered buzzer, medium size</td> + <td class="tdl">One near the poultryman's bedroom</td> + <td class="tdl">Relay, held open as long as power is on, closed by spring if interruption occurs</td> + <td class="tdl">One, at main switch of hatchery or brooder house</td> + </tr> + <tr> + <td class="tdl">Warn of dangerously warm temperature in freezer</td> + <td class="tdl">Battery-powered buzzer, medium size</td> + <td class="tdl">One, in or near the kitchen</td> + <td class="tdl">Temperature detector (sensitive thermostat)</td> + <td class="tdl">One, with bulb inside freezer</td> + </tr> +</table> +</div> + +<p class="spacer"> </p> + +<h3>How to Plan Your System</h3> + +<p>To save your time and steps when the telephone +rings for someone else in your family +who is some distance away, you can install a +simple bell or buzzer system to summon that +person.</p> + +<p>First, you must plan what you are going to +do. On a large sheet of paper, draw to scale +(roughly) a plan of your house and grounds, +including those places where phones are located. +It will help if you rule off your paper +in 1/8" or 1/4" squares and let each square +equal one foot. Show the location of poles +supporting your wiring.</p> + +<p>Next, pick out those areas where you or +others would likely be when someone else +would answer the phone and want to call you +to it.</p> + +<p>After you have thought about this, and +talked it over with members of your family, +show locations on your plan where you think +you would like to have buzzers or bells, and +show a button beside each telephone. (Generally, +you should have a bell or buzzer near +each phone, also.)</p> + +<p>Figure 3 shows diagrams of various types +of systems, and will help you determine the +number of wires you will have to install to +connect the buttons and bells that you have +planned.</p> + +<p>Inside, you will connect your transformer +and the various buttons and bells with ordinary +indoor bell wire. Outdoors, however, you +should use weatherproof 2-wire or 3-wire +telephone twist.</p> + +<p>Show on your plan the distances that must +be traversed by each type of wire, and show +the number of conductors in each. Don't +overlook the vertical distances (one floor to +another).</p> + +<p><span class="pagenum">[42]</span></p> + +<div class="figcenter"> +<img src="images/p42_fig3.jpg" width="400" height="207" alt="" /> +</div> + +<p class="caption">Figure 3</p> + +<h3>Materials You'll Need</h3> + +<p>Because no two situations are just alike, +it will be necessary for you to make your own +list of materials.</p> + +<p>As a guide, however, here is a list of +typical materials, with the quantities left +blank, for you to fill in as your own requirements +and measurements dictate.</p> + +<p class="hang"><br /> + 10-volt transformer<br /> +_____ Door buzzers<br /> +_____ Doorbells<br /> +_____ Weatherproof outdoor type bells<br /> +_____ ft. indoor bell wire<br /> +_____ ft. 2-wire weatherproof telephone twist<br /> +_____ ft. 3-wire weatherproof telephone twist<br /> +_____ lbs. staples (insulated)<br /> +_____ entrance insulators (for attaching + weatherproof to buildings and poles) +</p> + +<p>Because your transformer must be wired +into your regular house current, you should +have some help on this from an electrician +or other qualified person. Also, you should +get that person to review your plans and materials +list before you place an order.</p> + +<h3>Install According to Your Plan</h3> + +<p>With the aid of an electrician or other +qualified person, install your transformer, +and test it.</p> + +<p>You may then go ahead and complete your +signal system, checking carefully with your +plan, and making sure that your installations +are both electrically and mechanically secure.</p> + +<p>Test your system in all possible ways that +it might be used.</p> + +<h3>Demonstrations You Can Give</h3> + +<p>Build a demonstration board incorporating +a farm or home layout, with pushbuttons or +other controls and bells and buzzers appropriately +located. Show and tell how the system +would save time and energy.</p> + +<p>Show and tell how some of these work, and +their value: power-off alarm, freezer alarm, +fire alarm, driveway alarm.</p> + +<h3>For More Information</h3> + +<p>Ask your power supplier or your nearest +electrical supply house for catalogs or literature +on various types of signal systems, or +ask a dealer to show you equipment he has in +stock.</p> + +<hr class="chapter" /> + +<p><span class="pagenum">[43]</span></p> + +<div> +<img src="images/electprog_logo.jpg" width="50" height="70" alt="" class="split" /> +<img src="images/4h_logo.jpg" width="60" height="60" alt="" class="splitr" /> +</div> + +<h2 id="LESSON_NO_B-11">LESSON NO. B-11</h2> + +<p class="h4">Credit Points 2</p> + +<h3><b>FIRST AID FOR ELECTRICAL INJURIES</b></h3> + +<div class="figcenter"> +<img src="images/p43_injury.jpg" width="300" height="158" alt="" /> +</div> + +<p>What would you do if you saw someone who +had been hurt by electricity?</p> + +<p>Did you know that you could save his life, +if you had taken the time to learn and practice +a few simple rules of electrical first aid?</p> + +<p>First aid training equips you to know what +to do and what not to do for the injured until +medical help can be obtained. While the main +benefits are for you and your family, no one +can call himself a good citizen if he fails to +help a stranger who has been hurt.</p> + +<p>The information given here is only for electrical +injuries. Perhaps what you learn will +inspire you to take a complete course in first +aid.</p> + +<h3>What to Do</h3> + +<p>Learn how to prevent electrical accidents, +and what to do if an electrical accident occurs.</p> + +<p>1. Make an electrical hazard hunt in your +home or on your farm. Point out to your +parents everything that should be repaired +or replaced for safety's sake.</p> + +<p>2. Read the first aid suggestions that follow. +Learn them.</p> + +<p>3. Get to know the six steps that are outlined +for mouth-to-mouth rescue breathing. +Practice them on your brother, sister, or +parents. Teach the entire family how to do +it.</p> + +<h3>Electricity Can Kill</h3> + +<p>In this day of hundreds of uses of electricity, +you should know about electrical +dangers. Electrocution can occur from either +low voltage (household type) or high voltage +currents. Sometimes household voltages are +more hazardous because people underestimate +the dangers involved.</p> + +<p>A fraction of an ampere passing through +your heart muscles can be fatal. Your body +offers some resistance to the flow of electricity +to ground. If you are standing on wet +ground or in water, or if your skin is damp, +this resistance is greatly reduced.</p> + +<p><span class="pagenum">[44]</span></p> + +<p>Wire cables within walls and cords on appliances +are all insulated with a shock proof +covering. Continued use, age, or damage +may expose a bare wire and create a hazard. +The point of exposure need be only a fraction +of an inch. Cords are often used and abused. +Exposed wires and signs of wear are danger +signals.</p> + +<p>Always be wary of overhead wires. People +have been injured or killed when kite strings, +model plane control lines, irrigation pipe, +and water well equipment have come in contact +with the power supplier's or their own +overhead wiring.</p> + +<h3>Prevent Accidents</h3> + +<p>Underwriters' Laboratories (UL) have +taken steps to see that minimum safety standards +are met in the manufacture of electrical +equipment. Look for the UL label when you +buy cords or appliances. Never place cords +under carpets or furniture, or drape them +over a nail. Replace or repair worn cords +without delay.</p> + +<div class="figcenter"> +<img src="images/p44_underwriters.jpg" width="112" height="112" alt="" /> +</div> + +<p>Be especially careful when operating electric +devices in the bathroom. Keep in mind +the dangers of a wet floor, grounded metal +pipes, and wet skin. Turning on an AC radio +while you are taking a bath is asking for real +trouble.</p> + +<p>There may be shorts in electric devices. +Keep your hands dry when using them, and +do not touch them along with grounded metal +objects. If you ever get a slight shock, sound +the danger signal and do something about it.</p> + +<h3>Think, Then Act</h3> + +<p>Your first thought in rescuing a victim +from an electrical accident should be your +own safety. Speed is also important, because +a few seconds or minutes may save a +life.</p> + +<p>The first question you should ask yourself +is "Can I quickly turn off the power?" This +would be easier to do in the home than outside. +In the case of a victim trapped in a +bathtub from a radio accidentally knocked into +the water, it might mean simply removing +the plug from the wall outlet. If a victim is +found grasping shorted, permanently installed +equipment and cannot let go, the main switch +might be used for quick release of the current.</p> + +<div class="figcenter"> +<img src="images/p44_inthebath.jpg" width="200" height="100" alt="" /> +</div> + +<p>Outdoors, especially with high tension +wires, your danger in rescue is much greater. +To handle the victim, touch him only with a +long dry stick, dry rope, or a long length of +dry cloth. Be sure your hands are dry and +that you are standing on a dry board. A +broom might be a good lever to pry a victim +from a high tension wire but never use a +green stick containing sap.</p> + +<div class="figcenter"> +<img src="images/p44_drystick.jpg" width="225" height="143" alt="" /> +</div> + +<p><span class="pagenum">[45]</span></p> + +<h3>First Aid</h3> + +<p>Once the rescue has been made and the +victim is free of further danger, check to +see if breathing has stopped. If so, start +artificial respiration <i>immediately</i> and send +someone for a doctor.</p> + +<p>Artificial respiration must be started as +soon as possible after normal breathing +ceases. <i>Most persons will die within 6 minutes +or less if breathing stops completely +unless they are given artificial respiration.</i> +Precious minutes may have passed before +you get to the victim. Since the victim may +be within seconds of death by the time you +are able to touch his body, you should seek +to obtain an air flow to and from the lungs +<i>immediately</i>.</p> + +<p>The victim may seem stiff as an effect of +the current, so don't give up easily. Continue +the procedure for several hours. If +transportation is necessary, remember that +there may be internal injury, fractures, or +severe burns.</p> + +<h3>Mouth-To-Mouth Rescue Breathing</h3> + +<p>There are various effective ways to give +artificial respiration, each with its advantages +and disadvantages. The mouth-to-mouth +method is recommended as a good one to +master. It can be used on victims of drowning, +suffocation, and asphyxiation, too. +People have been known to save lives with +less exposure to the correct procedure than +you are getting by reading this. So, pay attention +and remember what you read.</p> + +<p>Step 1. Turn the victim on his back. Wipe +out victim's mouth quickly. Turn his head +to the side. Use your fingers to get rid of +mucus, food, sand, and other matter.</p> + +<div class="figcenter"> +<img src="images/p45_headposition.jpg" width="162" height="127" alt="" /> +</div> + +<p class="caption">Head Position</p> + +<p>Step 2. Straighten victim's head and tilt +back so that chin points up. Push or pull his +jaw up into jutting out position to keep his +tongue from blocking air passage. This position +is essential for keeping the air passage +open throughout the procedure.</p> + +<div class="figcenter"> +<img src="images/p45_pushjawup.jpg" width="117" height="137" alt="" /> +</div> + +<p class="caption">Push Jaw Up</p> + +<div class="figcenter"> +<img src="images/p45_pinchnostrils.jpg" width="137" height="137" alt="" /> +</div> + +<p class="caption">Pinch Nostrils</p> + +<p>Step 3. Take a deep breath, place your +mouth tightly over victim's mouth, and pinch +nostrils closed to prevent air leakage. For +a baby, cover both nose and mouth tightly +with your mouth. (Breathing through handkerchief +or cloth placed over victim's mouth +or nose will not greatly affect the exchange +of air.)</p> + +<div class="figcenter"> +<img src="images/p45_breathe.jpg" width="162" height="130" alt="" /> +</div> + +<p class="caption">Breathe</p> + +<p>Step 4. Breathe into victim's mouth or +nose until you see his chest rise. (Air may +be blown through victim's teeth, even though +they may be clenched.)</p> + +<p>Step 5. Remove your mouth and listen for +the sound of returning air. If there is no +air exchange, recheck jaw and head position. +If you still do not get air exchange, turn +victim on side and slap him on back between +shoulder blades to dislodge matter that may +be in throat. Again, wipe his mouth to remove +foreign matter.</p> + +<p>Step 6. Repeat breathing, removing mouth +each time to allow air to escape. For an +adult, breathe about 12 times per minute. +For a child, take relatively shallow breaths, +about 20 per minute. Continue until victim +breathes for himself.</p> + +<p><span class="pagenum">[46]</span></p> + +<h3>What Did You Learn? True or False</h3> + +<p>1. A broken arm should be splinted before +artificial respiration is applied to a victim +who is not breathing.</p> + +<p>2. A person who has been severely shocked +with an electric current should lie down.</p> + +<p>3. A doctor should be called even though +you successfully have revived a victim's +breathing.</p> + +<p>4. A fraction of an ampere through the +human heart muscles can be fatal.</p> + +<p>5. A copper wire would provide a better +path than your body for stray currents, therefore +all appliances should be grounded if +possible.</p> + +<p>6. Outside wires are never a hazard because +they are covered with insulation when +they are installed.</p> + +<p>7. Cords need not be repaired until you +can see bare wires.</p> + +<p>8. Tuning in an AC radio while you are +bathing is always dangerous, even though +your hands are dry.</p> + +<p>9. In an emergency, a broom is an acceptable +tool for prying a victim off a high +tension wire.</p> + +<p>10. In mouth-to-mouth breathing, an +adult's lungs should be filled 12 times per +minute and a child's 20.</p> + +<h3>Demonstrations You Can Give</h3> + +<p>Show how to deal with an electrical first +aid "problem" given to you by your leader.</p> + +<h3>For More Information</h3> + +<p>Ask your leader to have a first aid expert +put on a demonstration. (Many industrial +plants and power suppliers have such people.)</p> + +<hr class="chapter" /> + +<p><span class="pagenum">[47]</span></p> + +<div> +<img src="images/electprog_logo.jpg" width="50" height="70" alt="" class="split" /> +<img src="images/4h_logo.jpg" width="60" height="60" alt="" class="splitr" /> +</div> + +<h2 id="LESSON_NO_B-12">LESSON NO. B-12</h2> + +<p class="h4">Credit Points 3</p> + +<h3><b>HOW ELECTRICITY HEATS</b></h3> + +<div class="figcenter"> +<img src="images/p47_popcorn.jpg" width="300" height="168" alt="" /> +</div> + +<p>In ancient times, people thought that heat +was a material just as air is. They +called it "caloric". When something got +warm, they said, caloric flowed into it. +When something cooled off, caloric flowed +out of it. It did not bother them that they +could not see caloric. They could not see +air either!</p> + +<p>Now we know that heat is not a material. +It does not take up space. It does not weigh +anything. Instead, it is a form of energy. +And when we say that heat is a form of energy, +we mean that it can be used to do work.</p> + +<h3>What to Do</h3> + +<p>1. Make a simple resistance heater.</p> + +<p>2. Make some popcorn by:</p> + +<p>(a) conduction (b) convection +(c) radiation</p> + +<h3>"Resistance" Makes Heat</h3> + +<p>There are at least four ways that electricity +can make heat. The one that we'll +cover here is <i>resistance</i> heating. (The others +are: <i>dielectric</i> heating, where the lines of +force of an electrostatic field pass through a +non-conductive material and heat it; the <i>heat +pump</i>, which is a refrigerator in reverse; +and <i>electronic</i> heating, which uses high frequency +waves similar to radio waves to create +high speed movement of the molecules or tiny +particles which rub together to make heat.)</p> + +<p><i>Resistance</i> heating occurs because every +conductor of electricity opposes the flow of +current through it. Some conductors resist +more than others. When they do, a certain +amount of warming takes place. The more +resistance that is offered, the more heating +there is.</p> + +<p>Some materials, like silver, copper, and +aluminum, offer little resistance. We say +they are good conductors.</p> + +<p>Other materials, like iron, offer more +resistance. They are still conductors, but +not as good as the others mentioned.</p> + +<p><span class="pagenum">[48]</span></p> + +<p>The <i>size</i> of the conductor, and its <i>length</i> +are the other two things that affect its resistance. +The <i>smaller</i> it is, the greater its +resistance. Also, the <i>longer</i> it is, the +greater its resistance. Therefore, when we +only want to <i>move</i> electricity from place to +place, we want relatively large, "good" conductors. +Here, we do not want to make heat. +In fact, we want to avoid it, because too +much heat in the wrong place can cause a +fire.</p> + +<div class="figcenter"> +<img src="images/p48_filament.jpg" width="150" height="118" alt="" /> +</div> + +<p>But when we want heat, we choose relatively +small, "poor" conductors, and the +more heat we want, the longer they must be. +If you will think of the filament inside a lamp +bulb; you may recall that it is a very fine +wire, coiled so as to get a maximum length, +and made of tungsten which has a high resistance.</p> + +<p>Because of all these factors, this filament +glows at a white heat, and is a source of +both light and heat.</p> + +<h3>Make a Simple Resistance Heater</h3> + +<p class="hang"><i>Materials you will need</i>:<br /> +1 dry cell battery<br /> +1 foot iron picture wire<br /> +Pliers</p> + +<p>Use a short strand of iron picture wire +and hook the ends to the terminals of a dry +cell battery. Use pliers so that you do not +burn your fingers. Disconnect the wires as +soon as they become hot. Tell why the wires +heat.</p> + +<div class="figcenter"> +<img src="images/p48_resistance.jpg" width="175" height="100" alt="" /> +</div> + +<h3>Conduction is "Touching" Heat</h3> + +<div class="figcenter"> +<img src="images/p48_fryingpan.jpg" width="185" height="95" alt="" /> +</div> + +<p>Conduction occurs when you set a pan containing +food right on a heating element. An +egg cooking in a hot frying pan is a good example +of conduction at work. This method +is the most efficient single way of using electric +heat for cooking.</p> + +<h3>Convection Depends on Air</h3> + +<div class="figcenter"> +<img src="images/p48_oven.jpg" width="182" height="187" alt="" /> +</div> + +<p>Convection warms food in pans that are +not actually touching the heating element. It +uses the hot air around the element to carry +heat to the pan.</p> + +<p>Your oven in your range works by convection. +Most houses are warmed in winter in +the same way. The heat produced in a furnace +warms the air as it circulates through. +This air in turn keeps your body warm.</p> + +<p><span class="pagenum">[49]</span></p> + +<h3>Radiation is Like the Sun</h3> + +<p>Radiation heating is more difficult to explain. +It results when heat or energy waves +strike an object and are converted into heat. +The energy we receive from the sun is a good +example. When you are wearing dark clothes +on a chilly day, you may become uncomfortably +hot. The sunshine warms you even +though the air around you has not been heated. +Radiant energy has a way of being absorbed +by dark objects and reflected by light colored +or shiny surfaces. Did you ever notice how +snow melts faster on a black top road than it +does on a concrete road?</p> + +<div class="figcenter"> +<img src="images/p49_snowmelt.jpg" width="182" height="169" alt="" /> +</div> + +<p>The electric heat lamp is one of the most +familiar sources of radiant heat. Other examples +are panels and cables that are built +into the walls and ceilings of homes to provide +heat.</p> + +<h3>Make Popcorn 3 Ways</h3> + +<p>How do you make popcorn? Did you know +that you can do this kind of a heating job three +different ways?</p> + +<p class="hang"><i>Materials Needed</i><br /> +Popcorn<br /> +Cooking oil or shortening<br /> +Salt and butter<br /> +4-qt. saucepan, with cover. (A glass cover is preferred.)<br /> +Potholder<br /> +Electric range<br /> +2 250-watt heatlamps<br /> +2 spring clamp type lampholders<br /> +Wire mesh corn popping basket or wire mesh kitchen strainer (improvise a screen wire cover)</p> + +<p><i>First</i>, make popcorn the way you usually +do. Set a front surface unit control on the +range at "medium high". Pour enough oil to +very lightly cover the bottom of the pan. +When the pan is hot, pour in enough popcorn +to cover the bottom with one layer of kernels. +Use the potholder in one hand to hold the +cover on, and with the other move the pan +back and forth across the unit. When the +popping stops, remove from the heat.</p> + +<p>How did the heat get to the popcorn?</p> + +<p><i>Second</i>, make popcorn in the oven. Add +the oil to the pan, cover it and put it in the +oven. Turn the oven on, with the automatic +control set at 400°. When the oven indicator +light goes off, this means that the proper +temperature has been reached. With the +potholder, remove the pan and add one layer +of popcorn kernels. Replace the pan in the +oven. When the popping stops (listen for it) +remove the pan.</p> + +<p>What kind of heating took place here?</p> + +<p><i>Third</i>, make popcorn with the heat lamps. +Clamp the lampholders to the back of a chair +or other vertical support. They should be 6 +to 8 inches apart and pointed directly at each +other. Put about 2 tablespoonfuls of popcorn +in the Wire basket or strainer. Do not add +oil. Hold the basket midway between the two +lamps. When the popping stops, turn off the +lamps.</p> + +<p>What kind of heating was this?</p> + +<p>Now, butter and salt the popcorn you have +made and share it with others.</p> + +<h3>What Did You Learn?</h3> + +<p>1. How is heat transferred from one body +to another?</p> + +<p>2. Could chicks or pigs receive warmth +from a heat lamp without the air in the pens +becoming warm? Explain.</p> + +<p>3. How does a broiler unit in a range cook +meat?</p> + +<p>4. How does an oven bake food?</p> + +<p>5. Tell why iron picture wire was used +instead of copper wire for your heating demonstration.</p> + +<hr class="chapter" /> + +<p><span class="pagenum">[50]</span></p> + +<div> +<img src="images/electprog_logo.jpg" width="50" height="70" alt="" class="split" /> +<img src="images/4h_logo.jpg" width="60" height="60" alt="" class="splitr" /> +</div> + +<h2 id="LESSON_NO_B-13">LESSON NO. B-13</h2> + +<p class="h4">Credit Points 2</p> + +<h3><b>MYSTERIOUS MAGNETISM</b></h3> + +<div class="figcenter"> +<img src="images/p50_magnetism.jpg" width="182" height="245" alt="" /> +</div> + +<p>In ancient times, people found certain +rocks that clung together in bunches. +These rocks were very mysterious. People +didn't understand them and many superstitions +grew up about lodestones, as these rocks +were called. Lodestone (sometimes spelled +loadstone) means leading stone. People even +told Columbus not to sail out of sight of land +because a giant lodestone was just over the +horizon waiting to pull all the nails out of his +ships.</p> + +<p>The Chinese were the first to use magnets. +They found that if you hung a lodestone by a +string, one end of the stone would always +point in the direction of the North Star. They +had the first magnetic compasses.</p> + +<p>An artificial magnet can be made by stroking +or gently rubbing a piece of steel with a +lodestone. This piece of steel then can be +used to magnetize another piece of steel. +This can be continued on and on. Lodestones +are not always available but you can get the +same results with an electric current. So, +magnetism and electricity are very closely +related.</p> + +<h3>What to Do</h3> + +<p>Learn about magnetism by doing the experiments +that follow.</p> + +<p>Seeing is believing!</p> + +<p class="hang">Materials You Will Need<br /> +2 dry cell batteries (#905)<br /> +A few feet of No. 18 bell wire<br /> +3 steel knitting needles or similar hard steel<br /> +2 ft. of light thread<br /> +Sheet of light cardboard or stiff paper<br /> +Permanent magnet (bar or horseshoe)<br /> +Compass<br /> +1 or more large nails or spikes<br /> +Red and black china-marking pencils or crayons<br /> +<br /> +Iron filings<br /> +Wire cutters<br /> +Carpet tacks</p> + +<p>(Iron filings usually can be found under the +grinding wheel in a shop. If you can't find +any, rub some steel wool pads together to +produce bits of metal that will do.)</p> + +<h3>"See" a Magnetic Field</h3> + +<p>Cover the permanent magnet with the cardboard +or paper. Sprinkle iron filings on the +paper. Tap the paper and note the pattern +formed. Strings or lines of filings pass from +one pole of the magnet to the other. The +area covered by the filings is the center of +the magnetic field. To remember this, you +might compare the magnetic lines of force +that arrange the iron filings to the contour +strips in a farmer's field.</p> + +<p>This magnetic field is one of the important +things in our everyday life with electricity. +If it were not for the magnetic field, we would +not have electric motors. Telephones, +radios, television, and many other things we +use every day also depend on this magnetic +field.</p> + +<p><span class="pagenum">[51]</span></p> + +<div class="figcenter"> +<img src="images/p51_fig1.jpg" width="182" height="136" alt="" /> +</div> + +<p class="caption">Figure 1</p> + +<h3>Make an Electro-Magnet</h3> + +<p>You can make magnetism work for you by +winding several turns of insulated wire around +one or more large nails or spikes (soft iron). +Connect one end of the wire to the battery. +Touch the other end of the wire to the other +terminal for a few seconds and see how many +tacks you can pick up. Repeat the experiment +using as many turns as possible. How +many more tacks were you able to pick up?</p> + +<div class="figcenter"> +<img src="images/p51_fig2.jpg" width="182" height="138" alt="" /> +</div> + +<p class="caption">Figure 2</p> + +<p>You have made what we call an electromagnet. +When you disconnect the wire, the +nails fall off. This is one of the advantages +of an electromagnet. We can turn magnetism +on and off as we wish. Picture a crane operator +throwing the switch and picking up scrap +iron and steel. Then he opens the switch to +drop the scrap metals.</p> + +<p>Soft iron can be magnetized easily as you +have just seen, but loses its magnetism in a +short time. Steel is harder to magnetize but +holds its magnetism almost indefinitely.</p> + +<h3>Make a Permanent Magnet</h3> + +<p>Wrap the insulated bell wire around the +steel knitting needle. The wire should be +wrapped the full length of the needle. One +end of the wire is connected to the battery. +The other end of the wire is then touched for +just a few seconds to the other terminal. This +should make the needle into a permanent bar +magnet. If you did not get results, try two +batteries in series, wind more turns of wire +on the needle, and leave it connected a little +longer. Do the same thing with the second +knitting needle. In the same way, you can +magnetize a screwdriver, so that you can use +it to pick up and hold steel screws. Don't +do it unless you want your screwdriver to be +magnetized.</p> + +<div class="figcenter"> +<img src="images/p51_fig3.jpg" width="182" height="153" alt="" /> +</div> + +<p class="caption">Figure 3</p> + +<h3>See How They Attract and Repel</h3> + +<p>Take one of the magnetized needles and +hang it with a thread. A thread stirrup +(Figure 4) will help keep it level. Be sure +it is not near other large pieces of steel. +Watch the needle. Does it settle down, pointing +in one direction? (Check to see if this +is the same direction as your compass). If +it does, you have made a compass. The tip +of the needle pointing north is called the +North Pole (North-seeking pole). The other +end is called the South Pole. Mark the North +Pole with a stroke of the red marking pencil. +Mark the South Pole black. Do the same +thing with the second needle. You can show +this with a sewing needle, and a notched +cork, and a bowl of water. Rest the needle +in the notched cork, and float it on the water.</p> + +<p><span class="pagenum">[52]</span></p> + +<div class="figcenter"> +<img src="images/p52_fig4.jpg" width="182" height="126" alt="" /> +</div> + +<p class="caption">Figure 4</p> + +<p>Hold the compass near the North Pole of +the needle. What happens? Does the South +Pole of the needle attract the North or South +Pole of the compass? Try this with the second +magnetized needle. See if you can prove +the rule that like poles repel (drive away) +and unlike poles attract.</p> + +<div class="figcenter"> +<img src="images/p52_fig5.jpg" width="182" height="66" alt="" /> +</div> + +<p class="caption">Figure 5</p> + +<p>Connect one end of a wire loop to the battery +and run the wire directly over the compass. +Touch the other end of the wire to the +battery. Which way does the compass point +now? If you get some motion out of the compass +needle, this proves there is a magnetic +field around the wire when current is flowing. +This relation between electricity and magnetism +is the thing that makes electric motors +and generators work.</p> + +<div class="figcenter"> +<img src="images/p52_fig6.jpg" width="182" height="163" alt="" /> +</div> + +<p class="caption">Figure 6</p> + +<h3>Make Many From One</h3> + +<p>Lay the third needle (unmagnetized) on a +table and stroke it with one of the magnetized +needles. (See diagram) Always stroke it in +the same direction. Raise the magnetized +needle at least two inches on each return +stroke. Thus you can magnetize the needle +by using the other needle.</p> + +<div class="figcenter"> +<img src="images/p52_fig7.jpg" width="237" height="220" alt="" /> +</div> + +<p class="caption">Figure 7</p> + +<p>Use the wire cutters to cut the first magnetized +needle in short lengths. (Cover the +needle with a cloth to keep the pieces from +flying.) Can you show by using the compass +that each piece is a complete magnet? Hold +one end, then the other, of each piece to a +compass. Does each piece have both a North +Pole and a South Pole?</p> + +<div class="figcenter"> +<img src="images/p52_shortlengths.jpg" width="187" height="50" alt="" /> +</div> + +<h3>Magnetism and Animals</h3> + +<p>The things you have done show that electricity +and magnetism are related in many +ways. Magnetism is mysterious, and there +are still things to discover about it. It is +thought that animals and birds are aided in +their sense of direction by magnetism. It is +commonly known that when a person gets lost +in the woods, he tends to go around in circles. +Possibly this is caused by the earth's magnetic +field.</p> + +<p><span class="pagenum">[53]</span></p> + +<h3>What Did You Learn?</h3> + +<p>1. Where are natural magnets obtained?</p> + +<p>2. How can artificial magnets be made?</p> + +<p>3. What material is needed for a permanent magnet? For a temporary magnet?</p> + +<p>4. How can you find out which is the North Pole of an unmarked magnet?</p> + +<p>5. How many poles does a magnet have?</p> + +<p>6. Which magnetic poles attract each other?</p> + +<p>7. Why couldn't you make a compass out of a strip of plastic?</p> + +<p>8. What causes the compass to change direction +when a wire carrying battery current +is held over the needle?</p> + +<p>9. List the materials you would need and +tell how you would build a homemade compass.</p> + +<p>10. Tell what you enjoyed most about becoming +acquainted with mysterious magnetism.</p> + +<hr class="chapter" /> + +<p><span class="pagenum">[54]</span></p> + +<div> +<img src="images/electprog_logo.jpg" width="50" height="70" alt="" class="split" /> +<img src="images/4h_logo.jpg" width="60" height="60" alt="" class="splitr" /> +</div> + +<h2 id="LESSON_NO_B-14">LESSON NO. B-14</h2> + +<p class="h4">Credit Points 2</p> + +<h3><b>Give your appliances and lights a square meal</b></h3> + +<div class="figcenter"> +<img src="images/p54_starvation.jpg" width="400" height="263" alt="" /> +</div> + +<p>Would you say that having enough to eat +was pretty important in the home that +you know?</p> + +<p>The "food" for your appliances and lights +is electricity, and like you they must be +"fed" enough.</p> + +<h3>What to Do</h3> + +<p>1. List the appliances and lights in your +home.</p> + +<p>2. See if any of them are "starving" for +the electricity they need.</p> + +<p>3. Learn how the electricity gets to where +it's used.</p> + +<p>4. Make a chart of the electrical circuits +in your home.</p> + +<p>5. Make sure that each circuit is protected +with the right fuse or circuit breaker.</p> + +<h3>Count Your Electrical Blessings</h3> + +<p>Many people in much of the rest of the +world wish that they could trade places with +us, because we have so many electrical appliances +in our homes.</p> + +<p>Of course, we have not always had as +many appliances as there are today. When +electricity first came along, people used it +only for lights. Then, they began to add +flatirons, washing machines, refrigerators, +coffee percolators, and radios.</p> + +<p>Then more and more electrical things +were made for people to use and enjoy. Now +we have dozens and dozens of uses for electricity +in our homes.</p> + +<p><span class="pagenum">[55]</span></p> + +<p>How many different uses for electricity +are there in your home today? Ask your +parents how many there were when your +home was built or first wired. How many +were <i>common</i> when your parents began to +keep house?</p> + +<h3>Some Homes Are Behind Times</h3> + +<p>Many older homes were built before electricity +was available, and were wired later. +And like them, some older homes that +were wired as they were built had only enough +wiring for lights and a few other appliances, +because those were the only uses that were +known at that time.</p> + +<div class="figcenter"> +<img src="images/p55_rocking.jpg" width="182" height="104" alt="" /> +</div> + +<p>But people kept on living in these homes, +and kept adding to the uses they made of +electricity without adding to their wiring.</p> + +<p>What has this meant? Well, if electricity +were like cars and trucks, you could say +that some people are trying to put turnpike +traffic through a back-country dirt road!</p> + +<h3>Watch for Signs of Starvation</h3> + +<p>Of course, as your state has done with its +highways, some people have expanded and +modernized their wiring. But many others +have not yet seen this need, or if they have, +they may have to do it again.</p> + +<p>Here's why:</p> + +<p>Your power supplier delivers current to +you at the right voltage or electrical pressure. +If the wires in your house are large +enough, they will pass this full voltage on to +the appliances.</p> + +<p>But if your wiring is too small, the electricity +arrives at the appliances so weak +that they can't work properly, and much of +what you pay for is wasted.</p> + +<p>Here are some things you can watch for +in your own home. They will tell you whether +your appliances are getting enough electrical +"food" or not.</p> + +<p>1. <i>A shrinking TV picture</i>—If it draws +in from the sides of the screen, fades, loses +contrast, or if the sound becomes distorted, +you may have low voltage.</p> + +<p>2. <i>Too much fuse blowing or circuit +breaker tripping.</i></p> + +<p>3. <i>Heating appliances are slow to do their +jobs.</i></p> + +<p>4. <i>Lights dimming</i>, when motors or other +appliances are turned on.</p> + +<p><b>There Should Be Enough Ways +to Get "Appliance-Food" Around</b></p> + +<p>If appliances in your home show these +starvation signs, then you may not have +enough ways for the electricity to get to +where it's used.</p> + +<p>There are three kinds of these electrical +highways or circuits, and your home should +have enough of each:</p> + +<p>1. <i>General purpose circuits</i>—These +serve lights all over the house, and convenience +outlets everywhere except in the +kitchen, laundry, and dining areas.</p> + +<p>A rule-of-thumb is: There should be at +least one general purpose circuit for each +500 sq. ft. of floor space.</p> + +<p>2. <i>Small appliance circuits</i>—These are +not used for lights, but instead they supply +convenience outlets in the kitchen, laundry, +and dining areas where portable appliances +are most used.</p> + +<p>Every home should have at least two +small-appliance circuits.</p> + +<p>3. <i>Individual or special-purpose circuits</i>—One +of these is needed for each: electric +range, dishwasher, water heater, freezer, +automatic washer, clothes dryer, air conditioner, +pump, and house heating equipment.</p> + +<p><span class="pagenum">[56]</span></p> + +<div class="figcenter"> +<img src="images/p56_wiresize.jpg" width="250" height="255" alt="" /> +</div> + +<p class="caption">Wire sizes commonly used in homes</p> + +<h3>Each Circuit Big Enough</h3> + +<p>The capacity of each circuit is limited by +the size of its wires. The chart above shows +you the actual sizes of wires commonly used +in permanent home wiring, and what each +will carry. Notice that each size is given a +number, and the smaller the number, the +bigger the wire.</p> + +<p>Also notice that a given size of wire will +carry twice as many watts at 230 volts as it +will at 115 volts. (Watts are figured by +multiplying amps times volts.)</p> + +<p>General purpose circuits usually are +either Number 14 or Number 12 wire, at +115 volts. What is the capacity of each, in +watts? (Number 12 wire is recommended +for all new general purpose circuits.)</p> + +<p>Small appliance circuits are required to +be at least Number 12 wire.</p> + +<p>Individual circuits are always sized according +to the appliance they serve. Find +the size wire that should be used for a +10, 000-watt, 230-volt range; a 1500-watt, +115-volt dishwasher; a 4500-watt, 230-volt +clothes dryer. ________ ________ ________</p> + +<h3>Only One Fuse Size Right</h3> + +<p>A fuse in an electrical circuit is like an +alert traffic policeman—stopping everything +if there's danger. A circuit breaker serves +the same purpose, and the right size is installed +when the wiring is done.</p> + +<p>A policeman uses his brain to tell him +when to blow his whistle, but a fuse depends +on the size of the little fusible (meltable) +metal link that you see under the glass.</p> + +<p>If too great an electrical load is added to +a circuit, this link will melt and prevent a +dangerous overload. If you put in a fuse +with too heavy a link, it will not melt in +time, and the wiring and equipment may be +damaged.</p> + +<p>Therefore the right size of fuse is very +important, and is something that you should +check in your own home.</p> + +<p>See the chart above for the right fuse for +each size wire.</p> + +<h3>Make a Circuit Chart</h3> + +<p>At one or more places in your home there +is a box or panel containing the fuses or +breakers for the various circuits. Attached +to the inside of the door of each such panel +should be a chart something like this:</p> + +<div class="figcenter"> +<img src="images/p56_fusesize.jpg" width="212" height="182" alt="" /> +</div> + +<p>Notice that in our chart we have made +columns for a description of what each circuit +serves, its number or position in the +panel, and the proper size fuse for it.</p> + +<p>Because most such charts leave out this +last very important bit of information, you +should make a complete new chart, like the +one shown. Provide as many lines as there +are fuse positions. Paste or tape it to the +inside of the panel door.</p> + +<p><span class="pagenum">[57]</span></p> + +<p>Then, ask permission of your parents to +disconnect all the circuits by unscrewing the +fuses or flipping the circuit breakers. <i>Do +not touch anything but the fuse rim.</i> Then +reconnect them, one at a time, to find out +what each circuit serves. Turn on as many +lights as you can, to help you in your detective +work. Use a test lamp at those outlets +that do not have a light connected to +them. Write two or three words describing +each circuit on the proper line on your chart.</p> + +<p>On a separate sheet, keep track of the +appliances and lights that are on each circuit, +and add up the watts. (If the name-plate +of any appliance gives "amperes", +"amps", or "A" instead of watts, just remember +that amps times volts equals watts.) +This will tell you if any of them are overloaded. +Show this sheet to your parents.</p> + +<h3>Check the Wire Sizes</h3> + +<p><i>Disconnect the main switch</i>, and determine +the size of the wires in each circuit. +Don't include the insulation in your measurement.</p> + +<blockquote><h4><i>BE CAREFUL!</i></h4> +<p><b><i>Even though you have disconnected +the main switch, the wires coming +into it are still "live". So, do not touch +any wires. Instead hold the wire size +chart near them so that you can tell +which gauge each one is.</i></b></p></blockquote> + +<p>Write in the proper size fuse for each +circuit on your chart.</p> + +<h3>Replace Any Wrong-Size Fuses</h3> + +<p>Do the fuse sizes you have written on your +chart agree with the ones that are in place +in the panel?</p> + +<p>Get the right size fuses and replace any +that are wrong. Make sure that you have a +reserve supply of the right sizes, and that +they are handy for future use.</p> + +<h3>Talk it Over With Your Parents</h3> + +<p>Do you think that your home has enough +of the proper size circuits? If not, talk it +over with your parents. They may want to +ask an electrician to go over the wiring and +make the necessary changes.</p> + +<h3>What Did You Learn?</h3> + +<p>(Underline the right answer.)</p> + +<p>1. A (television set, radio) is very sensitive +to changes in voltage.</p> + +<p>2. Dimming lights mean (static in the +wires, an electrical overload).</p> + +<p>3. Wires that become warm from overload +make it (more expensive, cheaper) to +operate the equipment.</p> + +<p>4. A home of 2,000 sq. ft. should have +at least (three, four) general purpose circuits.</p> + +<p>5. One solution to low voltage symptoms +is (heavier fuses, more circuits).</p> + +<p>6. Full capacity for a Number 14 wire +circuit at 115 volts is (1725 watts, 3000 +watts).</p> + +<p>7. A room air conditioner should be on +(a general purpose, an individual) circuit.</p> + +<p>8. The purpose of a fuse is to (let you +disconnect the circuit, automatically prevent +overloading the circuit).</p> + +<p>9. The right size fuse is determined by +(wire size, the store where you buy it).</p> + +<p>10. A circuit chart should give (circuit +description and fuse size, the maker's +name).</p> + +<h3>Demonstrations You Can Give</h3> + +<p>Ask your leader to help you plan a demonstration. +You can show how lights dim +when too many other appliances are connected, +how a fuse protects against overloading, +and the danger of using too large a +fuse.</p> + +<h3>For More Information</h3> + +<p>Ask your Extension agent, power supplier, +or electrician for additional help.</p> + +<hr class="chapter" /> + +<p><span class="pagenum">[58]</span></p> + +<div> +<img src="images/electprog_logo.jpg" width="50" height="70" alt="" class="split" /> +<img src="images/4h_logo.jpg" width="60" height="60" alt="" class="splitr" /> +</div> + +<h2 id="LESSON_NO_B-15">LESSON NO. B-15</h2> + +<p class="h4">Credit Points 4</p> + +<h3><b>YOU CAN MEASURE ELECTRICITY</b></h3> + +<div class="figcenter"> +<img src="images/p58_measure.jpg" width="300" height="163" alt="" /> +</div> + +<p>Instruments that can detect or measure +the flow of electricity have helped to +make possible the wonders of electricity as +we know them today.</p> + +<p>Scientists in laboratories must have measuring +devices for experiments leading to +new uses of electricity. Power suppliers +must have instruments that tell what the generating +equipment is doing and to measure +the amount of electricity being sold to users. +Factories need instruments that keep tab on +electrical equipment to make sure electricity +is being used efficiently.</p> + +<p>In fact, almost anywhere you find electric +power at work you'll find electrical instruments—even +in your home. The one you +know best measures the amount of electricity +used. Another, in the family car, shows +whether the generator is charging the battery +or if the battery is discharging.</p> + +<h3>What to Do</h3> + +<p>1. Make a simple kind of direct-current +meter that will show you that there's a magnetic +field around a wire carrying an electric +current and that will detect a very tiny +current.</p> + +<p>2. Make a more refined D.C. instrument +(galvanoscope) and measure the voltage of +different sizes of dry batteries, and show +how an electric current can be induced.</p> + +<p class="hang">Tools and Materials You'll Need:<br /> +Pair of pliers, knife, small hammer<br /> +30 feet of No. 24 bell or magnet wire<br /> +Compass<br /> +Two coins—a penny and a dime<br /> +Fine sandpaper<br /> +Blotting paper<br /> +Plastic or cellophane tape<br /> +Wooden blocks (See Figure 4)<br /> +Glue<br /> +2 small nails<br /> +One #905 dry cell, a penlight battery, and two regular flashlight batteries<br /> +Table salt<br /> +Drinking glass<br /> +2 paper clips<br /> +Two machine bolts +<span class="pagenum">[59]</span></p> + +<h3>How They Work</h3> + +<p>Like many electrical things, most electrical +instruments depend on the action of +magnetism created by an electric current. +There is a magnetic <i>field</i> or lines of force +around any wire carrying an electric current. +If this field is controlled and made to +react on a sensitive device, like an easily +moved pointer, we have an electrical instrument.</p> + +<h3>Detect a Magnetic Field</h3> + +<p>First, let's prove that there is a magnetic +field around any wire carrying an electric +current. Take a piece of wire about +two feet long and scrape off about an inch of +insulation from each end. Connect one end +to a battery terminal. Make a loop of wire +that crosses the face of your compass, north +to south. Now touch the other end of the +wire to the other battery terminal.</p> + +<p>(DO NOT attempt to substitute +alternating current, as from a model railroad +transformer because its alternating +current will cause the compass needle to +swing rapidly from one side to the other.)</p> + +<div class="figcenter"> +<img src="images/p59_fig1.jpg" width="182" height="109" alt="" /> +</div> + +<p class="caption">Figure 1.</p> + +<p>Put your right hand beneath the wire so +that your fingers point the way the needle deflects, +and your thumb will point in the direction that the +current is flowing.]</p> + +<p>What happens? Your compass needle +should move to one side because it is very +sensitive to magnetic influences. This +proved that the wire created a magnetic +field or lines of force when we passed electricity +through it. (Figure 1)</p> + +<h3>Detect a Tiny Current</h3> + +<p>How sensitive is your simple electric +meter? Take about five feet of wire and +wrap it around your compass as in Figure 2, +keeping the turns bunched together as much +as you can. Leave about six inches at both +ends of the wire extended for leads. Scrape +the insulation off the last inch of both. Rotate +the coil and compass until the needle +and coil are parallel, both pointing north +and south.</p> + +<div class="figcenter"> +<img src="images/p59_fig2.jpg" width="175" height="70" alt="" /> +</div> + +<p class="caption">Figure 2</p> + +<p>Take a copper penny and a dime, and +clean off any corrosion or film on the coin +faces with a bit of fine sandpaper. Now take +a piece of blotting paper about the size of +the penny and dip it into strong salt water. +Place the damp blotting paper between the +penny and the dime. Place one of your compass +coil leads against the dime, and the +other against the penny as shown in Figure +3. Be sure you have good metal-to-metal +contact between the wires and the coins.</p> + +<div class="figcenter"> +<img src="images/p59_fig3.jpg" width="125" height="125" alt="" /> +</div> + +<p class="caption">Figure 3</p> + +<p>At the instant that you squeeze the leads +against the coins, watch what is happening +to the compass needle. It should move for +an instant from the north position each time +you press the leads against the two coins.</p> + +<p>Obviously, the little coin battery you have +just made produces a very weak electrical +current. Even so, your instrument should +be able to detect it.</p> + +<h3>Make a Simple Galvanoscope</h3> + +<p>Now let's make a meter that is a little +more practical to use. Broadly speaking, a +galvanoscope is an instrument that detects +the presence of electric currents. It sounds +complicated but it is really quite simple. It +is named in honor of an Italian professor +named Galvani who made important early +experiments with electricity.</p> + +<p><span class="pagenum">[60]</span></p> + +<p>A refinement of the galvanoscope is today's +galvanometer. Other related instruments +are the voltmeter and ammeter. These +are very important instruments to the electrical +engineer.</p> + +<p>Using a glass or anything three to four +inches in diameter, wind about 20 turns of +wire in a "bunched" coil as in Figure 4. +Wrap the coil at several points with cellophane +or plastic tape to keep it from unwinding.</p> + +<div class="figcenter"> +<img src="images/p60_fig4.jpg" width="175" height="210" alt="" /> +</div> + +<p class="caption">Figure 4</p> + +<p>Make a wood base for your coil as shown +in Figure 4. The compass support blocks +can be thin wood slats. Do not attach them +with steel nails or tacks. Use glue instead. +Hold the coil in the slot between the blocks +with glue or melted wax or use copper +staples. Place the compass on the supports +and rotate the base so that the compass +needle and coil are parallel, pointing north +and south.</p> + +<h3>Measure the Voltage of Batteries</h3> + +<p>Do you know what difference the size of +dry cell battery makes in the voltage it supplies? +Your meter can tell you.</p> + +<p>To test the voltage of batteries we must +be able to control our galvanoscope. To do +this, connect a glass of strong salt water in +series with the battery as shown in Figure +5. Make sure the wire ends immersed in +the salt water are scraped free of enamel.</p> + +<div class="figcenter"> +<img src="images/p60_fig5.jpg" width="200" height="138" alt="" /> +</div> + +<p class="caption">Figure 5</p> + +<p>With one of the batteries connected, move +the wires in the salt water first closer, then +farther apart (keeping them parallel to each +other) while watching your compass needle. +When the needle stays 15 to 20 degrees off +north, lock the wires in the salt solution in +place with paper clips.</p> + +<p>Now disconnect the battery you have been +using and connect a smaller battery. If both +batteries are fresh, the compass needle +should return to almost the same spot. This +proves that both batteries regardless of size +put out the very same voltage. The larger +ones, however, are designed to last longer.</p> + +<p><b>Measure the Difference +between Series and Parallel</b></p> + +<p>Using the salt solution as in the previous +experiment, connect two flashlight batteries +in series as shown in Figure 6. The compass +needle should move about twice as far +as it did with one battery connected. This +shows that when you connect batteries this +way you double their voltage.</p> + +<div class="figcenter"> +<img src="images/p60_fig6.jpg" width="200" height="133" alt="" /> +</div> + +<p class="caption">Figure 6</p> + +<p><span class="pagenum">[61]</span></p> + +<p>Now place your batteries side by side and +connect the two top terminals and the two +bases as shown in Figure 7. The compass +needle should move only as much as it did +for one battery. This is called a parallel +connection. You can see that this arrangement +does not double the voltage, even +though you used two batteries.</p> + +<div class="figcenter"> +<img src="images/p61_fig7.jpg" width="200" height="130" alt="" /> +</div> + +<p class="caption">Figure 7</p> + +<p>While you have this hookup, try reversing +the position of the leads connected to your +batteries. Notice that reversing the direction +of current flow in the coil causes the +compass needle to swing in the opposite direction.</p> + +<h3>Test for Induced Current</h3> + +<p>Make a simple coil by winding about 50 +turns of wire around a machine bolt core. +The bolt should be 1/4 to 1/2" in diameter +and about two inches long. Connect the coil +to your galvanoscope as shown in Figure 8. +Pass the coil back and forth close to the end +of a permanent magnet.</p> + +<div class="figcenter"> +<img src="images/p61_fig8.jpg" width="200" height="133" alt="" /> +</div> + +<p class="caption">Figure 8</p> + +<p>Notice a slight deflection of the compass +needle with each pass. You have shown that +electricity can be induced in a wire coil by +moving it through a magnetic field. Currents +generated in this way are called induced currents.</p> + +<div class="figcenter"> +<img src="images/p61_fig9.jpg" width="200" height="133" alt="" /> +</div> + +<p class="caption">Figure 9</p> + +<p>Now make another coil and core just like +the first one and arrange them and a connection +as shown in Figure 9. If you make +and break the current to the second coil, +you will build up and collapse a magnetic +field around the first coil and again induce +a current in it. You will see the compass +needle swing back and forth again.</p> + +<p>These last two experiments give you a +crude idea of how an electric generator +works, producing electric current by induction +as a coil-wound rotor revolves within +a magnetic field.</p> + +<h3>What Did You Learn?</h3> + +<p>What does every current-carrying wire +have around it? How does this help us to +measure electricity? How sensitive are +electrical instruments? What is the difference +in voltage between (a) a large and a +small dry cell? (b) batteries connected in +series and in parallel? (c) your original +connection and the reverse of it? What +similarity does the test for induced current +show between movement through a magnetic +field and the making and breaking of a direct +current?</p> + +<h3>Demonstrations You Can Give</h3> + +<p>Show others how your galvanoscope can +detect: whether a battery is producing current, +which way the current is flowing, and +whether a current is strong or weak. Demonstrate +how a current can be generated +using magnetism.</p> + +<h3>For More Information</h3> + +<p>Ask your power supplier representative +to show you some of the instruments used +by his organization, and to give you a brief +explanation of how they work. Ask him or +an electrician to give you a demonstration +of a split-core ammeter.</p> + +<p> </p> +<p> </p> +<hr class="full" /> +<p>***END OF THE PROJECT GUTENBERG EBOOK ELECTRICITY FOR THE 4-H SCIENTIST***</p> +<p>******* This file should be named 38036-h.txt or 38036-h.zip *******</p> +<p>This and all associated files of various formats will be found in:<br /> +<a href="http://www.gutenberg.org/dirs/3/8/0/3/38036">http://www.gutenberg.org/3/8/0/3/38036</a></p> +<p>Updated editions will replace the previous one--the old editions +will be renamed.</p> + +<p>Creating the works from public domain print editions means that no +one owns a United States copyright in these works, so the Foundation +(and you!) can copy and distribute it in the United States without +permission and without paying copyright royalties. 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+almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + + + + +Title: Electricity for the 4-H Scientist + Idaho Agricultural Extension Service Bulletin 396, June, 1962 + + +Author: Eric B. Wilson + + + +Release Date: November 16, 2011 [eBook #38036] + +Language: English + +Character set encoding: ISO-646-US (US-ASCII) + + +***START OF THE PROJECT GUTENBERG EBOOK ELECTRICITY FOR THE 4-H +SCIENTIST*** + + +E-text prepared by Kevin Handy, John Hagerson, Matthew Wheaton, and the +Online Distributed Proofreading Team (http://www.pgdp.net) + + + +Note: Project Gutenberg also has an HTML version of this + file which includes the original illustrations. + See 38036-h.htm or 38036-h.zip: + (http://www.gutenberg.org/files/38036/38036-h/38036-h.htm) + or + (http://www.gutenberg.org/files/38036/38036-h.zip) + + + + + +Idaho Agricultural Extension Service +Bulletin 396 +June, 1962 +T-1 + +ELECTRICITY FOR THE 4-H SCIENTIST + +Safety +Uses +Economy + + + + + + + +Division I +4-H Electric + +University Of Idaho +College of Agriculture + + + + +HOW TO USE THIS BOOK IN FULFILLING THE GOALS OF THE 4-H ELECTRIC PROJECT +FOR THE FIRST AND SUCCEEDING YEARS + + +The minimum goals for credit in the 4-H Electric project vary according +to the 4-H member's age and the number of years he or she has taken the +electric project. For example, if you are a 4-H member beginning the 4-H +Electric project at the age of 10, you will not be required to earn as +many credit points as a 14-year-old 4-H member beginning the 4-H +Electric project. However, if you are a 12-year-old in your second year +of electricity you must earn as many credit points in that year as a +14-year-old does in his or her first year. + +Each lesson or goal has been designated a certain number of credit +points. These are shown near the title of each lesson or goal. You +decide on the lessons you want to study, list them, and add up the +credit points. + +For a full year's 4-H project credit, the total of your credit points +should be at least as many as shown in the following table: + +Examples of reading the table below are as follows: (a) An 11-year-old +member is required to complete 13 credit points the first year, (b) A +14-year-old is required to complete 17 credit points his first year, (c) +A 14-year-old taking the electric project for the third year must +complete 16 credit points that year. + +We recommend that, if you are taking the 4-H Electric project, you start +with the first lesson in the book and go on through to the back of the +book in advanced years. But you may skip the less important or less +interesting parts so long as you learn the basic lessons. A way to find +out whether you know the basic lessons is to read them through and try +to answer all questions under the heading "What Did You Learn." If you +can answer these questions you may not wish to spend the time doing the +things listed under "What To Do." + + Minimum Number of Credit Points Required for Each Year's Work in + the 4-H Electric Project + + 4-H Member's| 4-H Member's Year in 4-H Electric Project + Age | + | 1st Year | 2nd Year | 3rd Year | 4th or + | | | | Later Years + 10-11 | 13 | 15 | | + 12-13 | 15 | 17 | 19 | 20 + 14-15 | 17 | 19 | 21 | 21 + 16 & over | 19 | 21 | 21 | 21 + + +This system of credit points makes it possible for you to do the things +you want to do with electricity and get credit for them in the 4-H +Electric project. + + +4-H Electric, Division I + + + + +TABLE OF CONTENTS + + + Lesson Credit Page + Number Title Points Number + How to Use This Book 1 + B-1 Getting Acquainted With Electricity 3 2 + B-2 Tools for Electricians 4 7 + B-3 Rewire a Lamp--Be a Lamp Detective 3 11 + B-4 Make a Trouble Light 3 15 + B-5 What Makes Motors Run 5 18 + B-6 Taking Care of Electric Motors 3 23 + B-7 Reading the Electric Meter 4 26 + B-8 Ironing is Fun 3 30 + B-9 Let's Be Friends With Electricity 2 35 + B-10 How Electric Bells Work--For You 3 39 + B-11 First Aid for Electrical Injuries 2 43 + B-12 How Electricity Heats 3 47 + B-13 Mysterious Magnetism 2 50 + B-14 Give Your Appliances and Lights a + Square Meal 2 54 + B-15 You Can Measure Electricity 4 58 + + + + UNIVERSITY OF IDAHO + COLLEGE OF AGRICULTURE + AGRICULTURAL EXTENSION SERVICE + Eric B. Wilson, Extension Agricultural Engineer + 1962 + +Published and distributed in furtherance of the Acts of May 8 and June +30, 1914, by the University of Idaho Extension Service, James E. Kraus, +Director; and the U. S. Department of Agriculture, Co-operating. + + + + +LESSON NO. B-l + +Credit Points 3 + +GETTING ACQUAINTED WITH ELECTRICITY + + +Electricity serves you best when you understand how it works and use it +properly. As a 4-H member, you should know about electricity and help to +show others the way to obtain its tremendous work-saving benefits as +well as how to use it with safety. + +A good way to think of electricity is to compare it with water. It acts +a lot like water. However it is made of tiny parts of atoms called +electrons. When there are more than the normal number of electrons in +anything, it is said to be negatively charged; when there is a shortage +of electrons, it is positively charged. As water flows downhill, +"seeking it's level," electrons flow from negative to positive, seeking +to "balance" the charge. + + +Electrical Conductors + +Even if you're never going to repair a lamp or make a chick brooder, you +should know about conductors and insulators. This is because you happen +to be a fairly good conductor of electricity. Electricity will pass +easily through you to other conductors--the ground, for instance. When +this happens you may get a shock, burn, or serious injury. But it +doesn't ever have to happen, if you learn to understand your friend, +electricity. + +Silver, copper, iron, aluminum and many other metals are very good +conductors. Water, acids, and salts are too. Electricity passes over or +through them very easily. Like water pipes, the larger the conductor, +the more electricity it can carry. When conductors are too small for the +amount of electrons trying to move over them, they get hot, melt, may +start fires. That's why wire size is important. + + +Electrical Insulators + +Insulators are the opposite of conductors. Electricity has trouble +passing through some materials. Rubber, most plastics, dry wood, oils +and glass are some of the good insulators. It's the amount and kind of +insulation that counts. If it has enough force, electricity can pass +through just about anything--even jump gaps! + +Electricity, like water, flows along the easiest paths. It is always +trying to get to the ground. The earth attracts it. It stays on the +wires unless a person, a wet branch, or some other conductor gives it a +path to the ground. Do not touch any wire which might be carrying +electricity. + + +Play It Safe + +If you should touch a "hot" wire accidentally and are standing on a dry +piece of wood, the conducting pathway to the ground is not good and the +electricity may keep running along its wire. But do not touch some other +conductor with another part of your body. This would complete a circuit +through your body and would be very dangerous. Always make sure there is +plenty of good insulation material or plenty of distance between you and +anything which might be carrying electricity. + +Remember, too, insulation is of little use when it is wet. Dew, mist, +rain, condensation, a damp floor can change the whole picture. If you +understand electricity and how it acts, you'll be safe enough, because +you won't take chances or expose yourself to injury. + + +Electrical Terms + +_Alternating Current_--Usually referred to as "AC," alternating current +is current which reverses its direction of flow at regular intervals, 60 +times a second. + +_Direct Current_--"DC" current flows only in one direction. Battery +current is DC. + +_Ampere_--Amperes are units by which the rate of flow of electrical +current (electrons) is measured. An ampere is 6.3 billion electrons +passing one point in a circuit, in one second. This compares with the +way the flow of water is measured in gallons per second. + +_Volts_--A volt is a unit to measure the tendency of electrons to move +when they are shoved. Voltage is the amount of "push" behind the +electrons. It's like water pressure in a pipe. Home power lines carry +115 volts (110 to 120 volts). For appliances such as electric stoves, +washers and driers, a second 115-volt line should be added, giving 230 +volts (220 to 240 volts). + +_Watts_--Watts equal volts times amperes. Light bulbs, electric irons +and other appliances are usually marked with the voltage they require +and the number of watts. + +_Kilowatts_--Your electric bill usually reads in kilowatt hours. A +kilowatt is 1000 watts. A kilowatt hour equals 1000 watts used for 1 +hour. One kilowatt equals about 1-1/3 horsepower. A kilowatt is usually +indicated by "kw" and a kilowatt hour by "kwh." + +_Circuits_--A closed circuit is one in which the electricity is flowing, +lighting a light, running a motor, or some other appliance. The circuit +runs all the way from the place the electricity is being generated to +your home, through the appliance or light bulb, and back to the +generator. + +Circuits are opened and closed by switches. When the circuit is opened, +the electricity stops at the switch. Before working on a switch, socket, +fuse, or any part of the wiring be sure to open the main switch. The +main switch is usually at the fuse box or near it. Appliances should be +disconnected when you work on them. Everyone in the family should know +where the main switch is so it can be pulled in case of accidents, fire, +flood, or windstorm damage. + +_Fuses and Circuit Breakers_--These are the safety valves of your +electrical system. The different electrical circuits in your home are +meant to carry only certain amounts of electricity. Some carry only 15 +amps, others can carry 20 or more. They are marked to show capacity. + +When a fuse burns out or a circuit breaker opens, look for an overload +of lights and appliances on the circuit before you try to replace the +fuse or close the circuit breaker. Without these safeguards, the +overloaded electric line will heat up and may start a fire. Even if no +fire starts, electricity will be wasted and the homeowner will be paying +for electricity that's doing no good. + +Remember: If you ever have to replace a fuse, pull the main switch +first. Keep a flashlight handy in your house. It seems that fuses +usually blow at night, and it doesn't pay to stumble or fumble around +electric wires in the dark. + + +WHAT TO DO: Make A Circuit Board + +So that you can show others how electricity travels from here to there, +and how it behaves under different conditions, make an electric circuit +board. + + + _Materials Needed:_ + + Piece of 3/4" board about 4" x 6" + l-l/2-volt No. 6 dry cell battery + Two pieces of bell wire, each 24" long, one black, one white + Two 10-penny box nails (3") + Three 3-penny box nails (1") + Two small screws or carpet tacks + Two 2-inch rubber bands + Two miniature sockets with solder terminals + Two l-l/2-volt flashlight bulbs + + _Tools Needed:_ + Ruler, pencils, hammer, pliers or vise. + + + +_Making the Board:_ + +1. Lay out the board with a pencil and ruler as indicated in Figure 1. + +2. Bend the three-inch nail as shown in Figure 2, using pliers, vise and +hammer. + +3. Pound the one-inch nails into the board for a half-inch at points A, +C, and D. Use the three-inch nail to make a hole a half-inch deep at B. +Put the crank nail in this hole and pound in a little farther. Attach +the lamp socket brackets at E and F. Stretch the rubber band as in +Figure 3. + +4. Lay out the electricity path, the circuit (Figure 3). Use the black +wire for the positive side of the circuit (the center pole of battery). +Twist it around the switch crank B, and the center pole of battery. Run +another piece to the outside terminal of bulb socket at E. Run white +piece to negative pole of battery from the other terminal at E. + +[Illustration: Figure 1 (Circuit Board)] + +[Illustration: Figure 2 (Switch)] + +5. Close the switch. The rubber band should hold the switch nail tightly +against nail at C. Does the bulb light? __________ If it doesn't, check +the connections. + +Now you have a circuit--a closed circuit when the electricity runs all +the way from the positive pole to the negative pole. The black wire is +the hot side, the live wire, because it carries the full load of the +battery up to the bulb. + +Remember, battery current is direct current, DC. In the case of +alternating current, AC, such as most homes and buildings use, the +electricity flows in first one direction and then the other. + +[Illustration: Figure 3 (Closed Circuit)] + + +Parallel Wiring + +To make this circuit hookup, attach another white wire to the negative +pole of battery and a terminal of the second flashlight bulb. Run a +black wire from the other terminal to the switch terminal at C (Figure +4). Close switch. Both bulbs will light. + +Trace the circuit. Electricity is going equally to each bulb, the same +amount that went to the single bulb. The difference is that the battery +will last only half as long. It's like a pail of water with two open +spigots. The pail empties twice as fast as it would with just one spigot +open. This type of wiring is called parallel wiring. If one bulb is +unscrewed, the other will stay lit. + +[Figure 4 (Parallel Wiring)] + + +Series Wiring + +To do this, run the negative wire to one terminal of the second bulb and +attach a wire from the other terminal to a terminal of the first bulb. +The other terminal connects with the switch at C (Figure 5). This is +series wiring. If one bulb is unscrewed, the other will fail to light +because the circuit is broken for both. Anything that breaks the circuit +has the effect of opening the switch. + +[Illustration: Figure 5 (Series Wiring)] + +Show there is a circuit through the bulb by screwing and unscrewing it. +Also, "jump" the socket by running the wire from C to the other terminal +of the bulb at E while it is unscrewed. Bulb at F will light. Trace this +circuit. + + +SUGGESTED DEMONSTRATIONS + +Using the Circuit Board, you can give many demonstrations of the way +electricity flows, works and behaves. + + +Water And Electricity + +To help others understand electricity better, draw a water system on an +electric circuit board paralleling the circuit. For the battery show a +water tank, pipes instead of wires, faucets instead of switches. +Somewhere on the board paste a comparison of electrical terms with terms +used in describing water, such as the following: + + Wire equals Pipe + Volts equal Pressure + Amperes equal Rate of Flow - gallons per second + Watts equal Pressure times Rate of Flow + Switch equals Faucet + Current equals Flowing Water + + +Show how to figure the wattage that a circuit protected by a 15 ampere +fuse can handle. Do it with actual things or cut-out pictures of light +bulbs, irons, toasters, coffee-makers, etc. + +You know that Amperes times Volts equal Watts. If the voltage is 115, a +15 amp circuit can handle 115 volts times 15 amps, or 1725 watts. + +The name plates on electric motors indicate the amperage at full load. +You can convert this to watts, of course, by multiplying amperage by the +line voltage. Motors require an additional amount of electricity when +they start. You need to allow for this fact, so fuses will not blow or +circuits trip when a motor is turned on. You will learn more about this +when you study electric motors. + + +For More Information + +Your leader has many other sources of information about electricity and +demonstrations you can perform. Ask him. Also, libraries have many books +about electricity and its history, which are very interesting and +useful. Maybe you can find an electrician, someone from your power +supplier, or an equipment dealer who will talk to your club on +electricity or electrical safety. + + +What Did You Learn? + +(Underline the correct answers then discuss in the group.) + +1. In a water pipe system water flows. In an electrical circuit +(electrons) (atoms) (charges) flow. + +2. Electricity or electrons flow (easier) (harder) (about the same) in a +conductor than in an insulator. + +3. Rubber is a good (conductor) (insulator) (ground). + +4. The most common material used as an electrical conductor is (glass) +(silver) (copper). + +5. The unit of electrical pressure or push is the (ampere) (volt) +(watt). + +6. The rate of flow of electricity is measured in (gallons) (amperes per +minute) (amperes). + +7. Volts times amperes equals (watts) (kilowatt hours) (alternating +current). + +8. A dry cell battery (stores) (makes) (uses) electrical energy. + +9. In a parallel circuit the electricity has (one) (two or more) (no) +paths to travel. + +10. In a series circuit with two bulbs and a switch the bulbs are +(brighter) (dimmer) (the same) as when they were in the parallel +circuit. + + + + +LESSON NO. B-2 + +Credit Points 4 + +TOOLS FOR ELECTRICIANS + + Who goeth a borrowing + Goeth a sorrowing + Few lend (but fools) + Their working tools + + Tusser 1524-1580 + + +Whenever a job comes up, it saves time and trouble when you have the +right tools and they are all where you can find them. Electrical work +takes some special tools and some everyday tools. + +If you have ever watched a good electrician at work, you've seen how +neatly he stores his tools in a box so every one of them is handy. When +a lineman climbs a pole, he has his regular tools in a holster on his +belt. Special tools are kept in a box in racks in the repair truck, all +ready for instant use. Wouldn't you like to have electrician's tools all +handy, ready for use, and know how to use them properly? + + +Basic Tools for Electrical Work + + +_Knife_ + +A good knife with a sharp blade is one of the most useful tools. A +camper's or electrician's type knife is probably best because it has +other useful parts besides the cutting blades--a screwdriver or punch, +for instance. Of course, you'll never use the cutting blades as a +screwdriver. This knife should be kept clean, dry, sharp, and free from +rust. Put a little oil on the joints from time to time. Remember, "Never +whittle toward you and you'll never cut yourself." + + +_Pliers_ + +A pair of electrician's pliers should be part of your kit. Wrap the +handles with plastic insulating tape. Even though you're not going to +work on "hot" electric lines, it pays to play safe. Later on, as you +learn more about electricity, you'll want a pair of needle-nose pliers +for the fine work. + + +_Screwdrivers_ + +You'll want a screwdriver which has true corners. A 4 to 6 inch plastic +handled screwdriver with a narrow blade is best. You'll probably need +more than one size to fit the various size screws you'll be turning. + +Screwdrivers are easily damaged if you try to use them as chisels and +pry bars, or use them in screw slots which are too large for the blade. + +You can be hurt by the screwdriver if you try to screw or unscrew things +you are holding in your hand. Keep your free hand away from the end of +the screwdriver. Place the work on a bench or where it can be handled +easily. + + +_Soldering Iron_ + +A good 100 to 250-watt electric soldering iron will be useful. Later on +you may want to buy a soldering gun, but unless you are doing a lot of +soldering it won't be necessary. A supply of resin-core electrician's +solder will be needed. Acid-core solder reacts with copper and in time +causes a bad splice. + + +_Tape_ + +Once it was necessary to use two types of tape on splices--rubber tape +with friction tape over it. Now there is a plastic tape on the market +which takes the place of both and has good insulating quality. It is +called electrical tape, or plastic tape, and resists water, oils (which +would damage rubber tape), and acids. You'll need a lot of tape in your +electrical work, so keep a roll on hand. + + +_Other Tools and Equipment_ + +As you go along in electrical work, you'll be adding tools and other +equipment, such as a trouble light and maybe an ammeter or voltmeter. +Other tools you'll want to add will be a Phillips screwdriver, open end +wrenches, a crescent wrench, small hack saw, hand drill and bits. + +You'll also be using some regular carpenter's tools such as hammers, +saws, and so on. Unless you use them frequently, you don't need to keep +them in your electrical kit. + +It's a good idea to start acquiring a supply of electrical +parts--lengths of wire, fuses, switches, sockets, plugs, and other items +that will come in handy. There are parts you can salvage from old lamps, +motors, and other equipment. Such a collection can be a real treasure +chest when you need a part in a hurry. But be sure to throw away all +faulty parts. + +[Illustration: Figure 1. Completed tool chest.] + + +WHAT TO DO: Build a Tool Chest + +To keep your tools always ready for use, a tool chest will be very +handy. It's the 4-H way to work. You'll be surprised how much easier it +makes a job when you have your tools, various parts and repair equipment +all in one place. You can make the chest (Figure 1) with a saw, plane, +screwdriver, pencil, ruler or carpenter's square, and hammer. + + +_Materials You'll Need:_ + +A piece of lumber 1" by 10" by 8 feet long. (1" lumber is actually only +3/4" thick--this is the thickness you'll be working with.) + +2 small hinges, with wood screws + +1 small hasp, with wood screws + +2 small handles with wood screws, or one large handle + +1 small chain, 10" to 12" long + +Some No. 6 penny finishing nails or wood screws about the same length + + +_Making The Chest:_ + +1. Cut your lumber into the following pieces: + +1 piece 10" x 18" for top + +1 piece 8-1/2" x 16-1/2" for bottom + +2 pieces 6" x 8-1/2" for two ends + +2 pieces 6" x 18" for front and back + +2. Lay out pieces as shown in Figure 2. + +[Illustration: Figure 2] + +Then, set up the two end pieces and nail to bottom section. Refer back +to Figure 1 as you go along to see that box is shaping up as shown. Nail +the front and back sections to the ends along the bottom. Wood screws +can be used instead of nails. + +3. Lay the top in place and attach hinges to the back side, about two +inches in from each end. + +4. Attach one part of hasp to the top, and the other part to front board +in center. Fasten the handles to each end. + +5. Attach chain to the top and front so the top will stay open when +chain is fully extended. + +Now you can invent your own improvements for your chest. You can paint +it, put your name on it, and your club emblem and name if you wish. You +can put a rack on the inside of the cover to hold your work sheets and +other booklets and materials. You can install special slots or straps to +hold each tool in its place along the sides of the box. Maybe you will +want to put some partitions in the box to separate various electrical +equipment such as wires, fuses, switches, and plugs. + + +_A Working Kit_ + +An accessory which you may want to add to your tool chest is an apron or +holster to wear when you are moving around on the job. An apron can be +made of a size of cloth about 18 by 20 inches. It should be folded up +from the bottom, and sewn to fit the number and size of tools you have. +Figure 3 shows such an apron. + +[Illustration: Figure 3. Apron.] + +You can make a lineman's holster in the same way, using plastic or soft +leather. Merely make belt loops by cutting on the dotted lines. A snap +fastener will hold the flap over the tools so they won't fall out. + +[Illustration: Figure 4. Lineman's Holster.] + + +Demonstrations You Can Give + +Show and tell others the proper handling, care and use of tools. + +Show and tell how to build an electrician's tool kit. + + +For Further Information + +Ask your power supplier or an electrician to tell the club about the +various tools of the electrician's trade and demonstrate them. Ask your +leader how to get exhibit material or information about electrical tools +and their use and then tell the club about them. + + +LESSON NO. B-3 + +Credit Points 3 + +REWIRE A LAMP--BE A LAMP DETECTIVE + + +[Illustration: The Line-Up Of Lamp Suspects] + +One of the duties of a law officer is to prevent crime. It's that way +with the lamp detective. You can become one. In the average home there +are lamps about to commit the crime of shocking people, starting fires, +and stealing electricity. Some are refusing to do their job well and +some are no-goods, sitting in closets or attics, doing nothing. You can +put these lamps to working again safely and well. Become the lamp expert +in your family. + + +What's In A Lamp? + +A lamp gives light for comfortable and convenient use in the home. It +consists normally of a stand, switch, cord, lampshade holder, and shade. +Some lamps have diffusing bowls which reduce glare and shadows. + +The most common fault found in an old lamp is in the cord, but sometimes +the switch or the wiring in the lamp is bad. Look over all the lamps in +your home and find the ones needing to be fixed. + + +WHAT TO DO--Rewire A Lamp + +Somewhere around your house you can probably find a lamp that is no +longer used or needs repairing. You can make it useful again and at the +same time learn how to wire a lamp. + + +_Materials Needed_: + +Tools: Pocket knife, small or medium screwdriver, and pliers +(electrician type is best). + +_New Lamp Cord_: For each lamp to be rewired, you'll need 6 feet of cord +plus the length of wire within the lamp stand. Lamp cord wire comes in +two sizes, No. 18 and No. 16 AWG (American Wire Gauge). No. 18 is +smaller than No. 16, but is adequate for most lamps. Cords are made with +surface coverings of several different materials: braided cotton, rayon +or silk, and molded rubber or plastic. Braided cord is decorative, but +rubber or plastic is easier to work with and is usually more desirable. + +_Switch_: If the switch is bad, get a new one. Socket switches are made +with push-through, turn-knob, or pull-chain controls. The pull-chain +type is seldom used on modern table or floor lamps. Your lamp may have a +separate push-switch in the base. In this case, get the same kind for +replacement. Some switches are "3-circuit" switches for use with high, +medium, and low-light bulbs. + +_Plug_: Plugs are made of various materials, mostly hard rubber or +molded plastic. Some have a shank or handle for better grasping. This +type is more desirable. The plug on the old cord may be good, and if so, +may be used on the new cord. + + +How To Do It: + +1. If the plug on the old cord is good and you plan to use it, remove it +from the old cord. + +2. Measure and cut a new lamp cord equal to the length of the cord +within the lamp, plus 6 feet. + +3. Pass one end of the new cord through the center of the plug. Strip 2 +inches of the fabric insulation off cord, or in case of a rubber cord, +split cord back two inches. Be sure no bare wire shows in long split +section (Figure 1). + +4. Use knife to strip insulation off wire for 3/4" on end of each cord. +Be careful. Don't cut yourself. Don't cut wires. Use a light touch, +slope the knifeblade and slice with knife edge away from you (Figure 1). + +[Illustration: Figure 1 (Ready to Wire Plug)] + +5. Twist exposed strands of each wire tightly to make a good conductor, +and place each conductor around its proper terminal in the direction in +which the screw tightens (Figure 2). + +6. Tighten screws on terminal posts. Pull cord until slack is out. Lay +aside until ready to attach to lamp. + +[Illustration: Figure 2 (Attaching Cord to Plug)] + +7. Remove lamp shade, shade-holder, bulb, and diffusing bowl, if there +is one. + +8. Separate the metal shell of socket from its cap by pressing on shell +at place marked "press," and pull socket from cap. + +9. Pull on socket body to get some slack in lamp cord. Loosen screws and +detach cord. Pull cord out through base of lamp. You can splice new cord +to the old one and use the latter to "string" the new wire. + +10. Pass the new cord up through the lamp base and socket cap, tie a +simple half-hitch knot in the cord to prevent strain on the terminals, +and attach wires to the terminals on the socket (Figure 3). If there is +likely to be any strain on cord, use an Underwriters' knot. Twist +strands and attach wire in direction in which screw tightens. + +11. Pull slack out of cord in lamp so that socket rests in socket cap, +replace shell and reconnect cap. Be sure the fiber insulator is in the +shell. You'll feel or hear a click when the notches in shell are locked +to the projections in the cap. + +12. Replace bulb, inspect carefully, and test. (In floor lamps where the +cord runs through the center post and out under the base, the cord will +last longer if it is fastened with tape so it doesn't rub edge of lamp +base when lamp is moved.) + +13. If the lamp has a porcelain socket, simply disconnect the wires at +the terminals, remove the old wire and connect the new one. + +[Illustration: Figure 3 (Socket and Switch Assembly)] + + +What Did You Learn? + +Underline correct answers then discuss in the group. (There may be more +than one correct answer.) + +1. The part of the lamp that usually wears out first is (the socket) +(the cord) (the plug). + +2. Lamps that waste electricity are those which have (bad wiring) +(frayed cords) (dirty shades or bulb). + +3. To unplug a lamp you should grasp (cord) (plug) firmly and pull. + +4. Wire in lamp cord usually comes in sizes 16 or 18. Size 16 is the +smaller (true) (false). + +5. In fastening wire around a terminal post it should go around in a +(clockwise) (counter-clockwise) direction. + +6. When the switch on a lamp is turned off, the electricity only goes as +far as (the wall plug) (the switch). + +7. An Underwriters' knot should be used (only when there is room for it +in the plug) (whenever there is likely to be strain on the cord, even if +you have to replace the plug with a larger one). + + +SUGGESTED DEMONSTRATIONS + +Show how to inspect a lamp and its cord. You might tie tags on the cord +and lamp at points of danger or failure--at the plug, wear points next +to lamp base, bad sockets. + +Demonstrate the process of repairing a lamp cord, socket and plug. + +Make a board display of the parts of the lamp socket showing cord +attached. + +Make a display of the types of lamp cords and plugs in common use. + +Using two lamps, one with clean bulb and shade, the other dusty, show +how the former gives more light. + + +For More Information + +Lamps have an interesting history. Look it up in your local library. Ask +someone from your power supplier or electric dealer to talk to the club +about the different kinds of lamps. Your leader has or can get +additional information on lamps, if you wish. + +[Illustration] + + +What Did You Exhibit + +What Did You Demonstrate + + + + +LESSON NO. B-4 + +Credit Points 3 + +MAKE A TROUBLE LIGHT. + + +A handy piece of equipment in the home and on the farm is a heavy-duty +extension cord with a shielded light and a side outlet on it. When you +want to work on the car or tractor in the yard at night, the trouble +light is better than a flashlight. You can use it both for light and as +an extension cord. It is safer than matches or a lantern, especially +around the garage or barn. + +It is easy to make a trouble light, and it gives you good practice in +electrical work. Of course you can buy one, but you wouldn't have the +fun of making it nor would it suit your needs. Trouble lights are not +for permanent use--they're for emergency use and to provide light or +electricity in places where they are seldom needed. When you find a +trouble light being used as permanent wiring, that's the place to +install an outlet. + + +What Size Cord? + +Choose the right kind of cord. What length will be best for your various +uses? A cord too long may be bothersome to use and store. What will be +the heaviest load you are likely to put on the cord, in amperes? Check +appliances you may want to connect to it. No. 16 wire can carry 10 +amperes safely for a distance of 50 feet, while No. 18 can carry only up +to 7 amperes for a distance of 40 feet. You'll want a "hard service" +cord, called S, ST, or SO-type cord by electricians. Junior hard service +cords, known as SJ, SJT, or SJO, are fine for lighter duty. + + +Cord, Plug and Guard + +A rubber-handled socket should be used for safety and to withstand hard +knocks. It should have a switch on it, preferably a push switch in a +recess in the handle. + +The connector or attachment plug should be of rubber or solid plastic +and have a metal cord grip fastened to it. This grip will hold the cord +firmly and prevent strain on the terminal connections. + +[Illustration: Finished Trouble Light] + +Get a good lamp guard. If the wire is too light, it may bend and break +the bulb when hit or dropped. For the lamp itself, get a rough service +lamp. An ordinary lamp won't last long with rough usage. + + +How to Make the Trouble Light + +_Tools Needed:_ + +Your 4-H electrician's kit or screwdriver, knife and soldering iron + +_Materials Needed:_ + +1. About 20 feet of 2-wire, No. 16 heavy duty (hard service) + +2. A rubber-handled socket with switch and a side outlet + +3. A shielded lamp guard + +[Illustration: Materials Needed] + +4. A good connector plug cap, preferably with a clamp-type grip for the +cord + +5. A rough service lamp bulb + +6. Solder and flux + + +_Steps to Take:_ + +1. Remove about 2 inches of the outer covering of cord at one end. + +2. Separate the wires and cut away the filler material. + +3. Remove 3/4 inch of the conductor insulation from the end of each wire +and tightly twist the strands together to form a firm conductor. Be +careful not to cut any of the fine wires. Ends may be soldered. + +4. Slide the plug in position on the cord. + +5. If there is no cord grip, tie the underwriters' knot (Figure 1). If +there isn't room enough, make an "S" loop by passing the wires around +the prongs before fastening them to the terminal screws as explained in +the next step. + +6. Loop the bare part of the wire around the screw in the direction the +screw is turned to tighten (clockwise direction). This will prevent the +wires from being forced out from under the head of the screw as it is +tightened. Now repeat with the second wire, wrapping it around the other +prong of the plug. + + +_Connecting the socket._ + +1. Separate the parts of rubber-handled socket (Figure 2). + +2. Prepare the other end of the cord as in steps 1, 2, and 3 above. + +3. Insert the cord through the rubber handle and socket guard. + +4. Tie the holding knot (underwriters' knot) as explained in Step 5. + +5. Connect wires to terminal screws and assemble the rubber-handled +socket. + +6. Screw in the rough service lamp and test your cord. + +7. Put the shielded lamp guard on the socket and tighten the holding +clamp until it is firmly in place. You are now ready to use or +demonstrate your trouble light. + +8. After you've made your trouble light, decide on a good place to keep +it where it will be handy for use. Loop it carefully and hang it over a +wooden dowel rather than a nail. It will last longer. + +[Illustration: Figure 1 Tying an Underwriter's Knot] + +[Illustration: Figure 2 Disassembled Light] + + +What Did You Learn? + +(Underline correct answer) + +1. A Junior Hard Service Cord is known as an (SO-Type) (SJO-Type) cord. + +2. You disconnect a cord by (jerking it from the socket) (grasping plug +and pulling it out). + +3. Brass sockets are unsafe because (they break too easily) (the exposed +metal can cause short circuits). + +4. Rubber-covered cord is safer for emergency cords than fabric because +(it will stretch) (it will insulate and protect the wires inside). + +5. In a trouble light (any kind of bulb will do) (a rough service bulb +is best). + + +Ideas for Demonstrations and Exhibits + +1. Show how to make your trouble light and a method of storing it. + +2. Show a safe trouble light, and an unsafe trouble light with danger +points marked. + +3. Show cutaway pieces of different types of cord. + + +For More Information + +Ask your power supplier, county highway engineer, police official or +leader to tell you about various types of portable emergency lights and +their uses. + + + + +LESSON NO. B-5 + +Credit Points 5 + +WHAT MAKES MOTORS RUN + + +What makes an electric motor run? Can you make an electric motor that +will run? Certainly you can, and by doing so you'll learn why it runs. +It won't be mysterious any more and you'll be ahead of all the millions +of people who use motors every day and never know why or how the motor +converts electrical energy into useful power. + +[Illustration] + + +Motors Are Magnets + +You know how one end of a compass needle always points to North. No +matter how you turn the compass, the same end of the needle always +swings to the North. The earth itself and that small compass are both +magnets (Figure 1). Each has a North pole and a South pole. Around the +poles of each there are magnetic fields, invisible lines of force that +attract and repel. + +[Illustration: Figure 1. The same end of the compass needle always +points to the earth's magnetic North Pole.] + +The N poles _repel_ each other and so do the S poles. The N and S poles +_attract_ each other. In other words, opposite poles attract; poles that +are alike repel each other. + +Lay 2 bar magnets on a table side-by-side. If both N poles are at one +end, they'll repel each other and almost flip around until there's a N +pole lying next to a S pole (Figure 2). + +[Illustration: Figure 2. Small bar magnets laid side by side move so +that the North pole of one is near the South pole of the other.] + +Now suppose we place one of the bar magnets on the table. The other, +we'll fix on a pivot so it can spin around. This one we'll move so its N +pole almost touches the fixed magnet's N pole. As soon as we release it, +the movable magnet will spin around so its S pole will be near the N +pole of the stationary magnet. That's an electric motor--almost. + +[Illustration: Figure 3. A movable bar magnet pivots so its South pole +is near the North pole of a stationary magnet.] + +It's not quite a motor because the rotating magnet will just move as far +as it has to in order to get the opposite poles together. You might be +able to cause the movable bar magnet to make turn after turn. You could +do this by turning the fixed magnet quickly end for end. This wouldn't +be very practical as a motor. + + +We Can Improve It + +If we could change the pole on one end of the rotating magnet just as +soon as it reaches the attracting pole, it could make a complete circle. +In doing that, the pole at the near end of the rotating magnet would be +repelled by the stationary magnet and pushed away. As soon as the +opposite end of the rotating magnet would come into the magnetic field, +it would be drawn to the stationary magnet. In order to keep the "motor" +running, we would have to constantly change the poles at each end on +every half revolution. + + +We Need An Electromagnet + +We can't reverse the poles on simple bar magnets, but we can on +_electromagnets_. We can make one by wrapping a wire several times +around an iron core to form a coil. This magnet will also have a N and a +S pole when connected to electrical current. The big difference is that +the poles can be changed instantly by reversing the current in the wire. + + +Switching Poles Automatically + +The rotating electromagnet will have to be connected to the 2 wires +through which we pass the current. Since it's rotating on a center +shaft, we can't have a solid connection. Instead we have to extend the +wires from the coil out along the shaft and let the electric contact be +made with brushes which touch the wires along the shaft. + +[Illustration: Figure 4. A rotating electromagnet changes poles as +contacts are made first one way, then the other.] + +This is a simple way to reverse the current in the coil of the +electromagnet. + + +Increasing Efficiency + +Instead of using only one pole of a stationary magnet, we can use both. +This is done by shaping the stationary magnet around the path of the +rotating electromagnet. This way we have the benefit of the attracting +and repelling forces from both poles. The effect is doubled. + +We can also wrap wires around this circular iron and make an +electromagnet of it. But when we wire this magnet we use no brushes +because we want the current to flow in one direction only. + +The stationary electromagnet is called the _field_. The rotating +electromagnet is the _armature_. + + +WHAT TO DO: Make A Motor + + +_Tools Needed:_ + +Pocket knife, hammer, vise (or 2 pairs of pliers). + + +_Materials Needed_: + + 1 roll of No. 24 enameled wire + 1 roll of electrician's tape + 3 - 4" (20-penny) nails + 4 - 2-1/2" (8-penny) nails + 4 - 3" brads (10 penny) + Wood board for motor base + 2 staples or 4 small brads + 2 tacks + 2 - 3 volt dry cell batteries (or a 6 + volt transformer). + + +Step No. 1-Armature + +Wrap about 1-1/2" of a 4" nail with two layers of tape. This will be the +shaft. + +The iron core will be made of two pairs of 2-1/2" nails. Wrap tape +around each pair with heads and points alternated. + +Center both pairs on each side of the shaft. Place them about 1" from +the head of the shaft nail. Wrap them together with two layers of tape +from tip to tip. + +Start at the shaft and wind No. 24 enameled wire to one end and back. +Then do the same on the other end. Always wind in the same direction. +Leave 6" of spare wire at start and finish. + + +Step No. 2-Commutator + +Scrape all insulation off the ends of the wire. Bend the bare ends back +and forth as shown. Lay them flat over the taped shaft-one on each side +of the shaft. + +Hold the commutator down with narrow strips of tape. Wrap tightly near +the core and at the opposite end. + + +Step No. 3-Field + +Make the core by bending two 4" nails in the middle at right angles. +Space the heads about 3" apart to form a horseshoe. Wrap together with +two layers of tape. + +Wind about 400 turns of wire around the center. Leave 4" of spare wire +at start and finish. Attach to wood base with staples at each end of +the wire. Small brads, bent over, will do just as well. + + +Step No. 4--Armature Supports and Brushes + +Scrape the insulation from the ends of two 6" pieces of wire. Tack +them to the base and bend them as shown to make brushes. + +Drive two pairs of 3" brads into the base about 3-1/4" apart and in a +line midway between the field poles. Wrap wire around the supports to +form armature bearings. + +Scrape insulation off ends of wire from the field. Connect one end to +a brush wire. + + +_Assemble As Shown_ + +Adjust the position of commutator and tension of brushes against it for +best operation. + +Take the armature off the motor and connect the commutator wires to a +dry cell battery. Test the polarity of each end of the armature with a +compass. Switch the connections on the commutator and test again. See +how the compass needle changes direction? + +With the armature still off, connect the field coil directly to the dry +cell. Test the polarity of each end of the field with the compass. How +can you reverse the polarity? Try it. It's easy. + +Reassemble the motor again and start it. Push the field poles slightly +out of alignment with the turning armature. What happens to the motor's +speed? Can you tell why? + +This time, push the field poles completely out of the way. Test the +polarity of the armature as you slowly turn it by hand. Do you see what +happens and why it does? + +Try to reverse the direction of rotation of your motor by reversing the +connections at the battery. What happens? Can you explain why? + + +Demonstrations You Can Give + +Make a display board showing the parts of the toy motor and explain how +each part works compared with the parts of a commercial motor. + + +For Further Information + +There are several other types of toy motors you can build. Your club +leader or power supplier can help you find information about them. + +1. Did your toy motor run? + +2. Did your motor speed up or slow down when you pushed the field poles +out of line? Why? + +3. What happens to the magnetic polarity of the armature when you turn +it slowly by hand and check it with a compass? + +4. How can you reverse the direction of rotation of your toy motor? + +Is there another way too? + +What is it? + + + + +LESSON NO. B-6 + +Credit Points 3 + +TAKING CARE OF ELECTRIC MOTORS + + +Through the magic of electric motors, much of our work is done faster +and better at lower cost than we could do it without the help of the +electric motor. People who use motors and treat them properly have much +more time for other work and for leisure time activities. A +1/4-horsepower motor running quietly and steadily hour after hour will +do the work of one man, and operate all day for about 5 cents without +tiring. On many jobs it will work without "supervision", turning on and +off automatically, as required. It does this on water pumps, in heating +and cooling units, and on fans and similar appliances. + +All that a motor needs to do its work is electricity and a little care. +Let's see what you can do to give proper care to motors in your home and +on your farm. + + +You'll Need + +A light oil (SAE 10) for motors of less than one horsepower and a +slightly heavier oil (SAE 20) for larger motors. See if you need grease +for cups which may be on large motors. If so, be sure you use +ball-bearing grease and not ordinary cup grease. Cotton waste or clean +rags will be needed for wiping off the motors, and a tire pump or vacuum +cleaner for blowing out the dust or dirt. + +[Illustration: Some motors have instructions for oiling on the +name-plate.] + + +WHAT TO DO + +1. First, make a list of all the electric motors that work for your +home. You may wish to make a separate list for your farm buildings. +You'll probably be surprised at how many there are. Don't forget the +sewing machine, the refrigerator, the freezer, the vacuum cleaner and +other small but important motors. Don't touch any motor that is running. +Disconnect them before you touch them. + +2. Make a motor service chart with columns headed: Use, Location, +Horsepower, Volts, Amperes, Service Required, Date Serviced and What was +Done. (See sample) Then list all the motors that require any servicing. +Some will have the instructions on the motor or appliance; the +instruction booklet that came with the motor or appliance will also tell +what servicing is required. + +_Step 1._ Plan the job. Start with the motors in the home. Then you can +care for the motors on the farm. + +_Step 2._ Be sure that any motor on which you are going to work is +disconnected. Then wipe the outside case clean with a cloth. If the +motor has openings in the end, use a vacuum cleaner to suck out dust, +dirt or chaff. A tire pump may also be used to blow out this dirt. If +you use compressed air, be sure the pressure is not high as it may +damage wiring inside the motor. Dust-proof motors should be used in +dusty or dirty places. + +_Step 3._ + +[Illustration: If there are oil holes, oil according to the +manufacturer's instructions.] + +If there are no instructions, remember a little oil goes a long way as +far as motors are concerned. Motors of less than one horsepower require +only 3 or 4 drops (not squirts) of oil every 3 or 4 months if the motor +is used frequently. Too much oil can damage the motor. It spoils the +insulation. + +If there are no oil holes or grease cups on the motor, it is probably +lubricated by means of grease sealed in the bearings at the factory, or +it may use greaseless bearings, and does not need to be oiled or greased +periodically. Indicate on your chart all motors which need periodic care +and see that it is given according to schedule. + +Wipe away any excess oil or grease. Be sure oil holes are capped or +covered. + +_Step 4._ Reconnect motor and run for a moment. + +_Step 5._ Record on the chart the date you serviced the motor and what +was done. + + +What Did You Learn? + +How many motors are there in your home? ______ On the farm? ______ + +How many motors need regular oiling or grease? ______ + +How many are less than one-horsepower? ______ + +SAE Oil ______ is used to oil motors up to 1/2 horsepower. How much +oil?______ + +SAE Oil______ is used for larger motors. + + +Demonstrations You Can Give + +1. Show how to clean a small motor. + +2. Explain proper lubrication of motors. + +3. Using the chart prepared in this work sheet, give a talk about the +motors that work for you-the job each one does, which ones need oil or +grease, which need no attention, and why, etc. + +4. Use a homemade toy motor to explain "what makes motors run." + +5. Show proper way to replace worn cord on a small motor. + + +For Further Information + +Ask your county Extension agent or 4-H leader for more literature on +motors. They can help you obtain a film or a speaker such as a power +supplier, a local electric dealer, or electrical contractor to discuss +motors. + +Also visit your public library and see a science teacher for more +information on motors. + + +ELECTRIC MOTORS SERVICE CHART Sample + +Use a table like the following to list the motors around your farm and +home. + + ---------------------------------------------------------------------- + Motor | Location |H.P.|Volt |Amp |Service |Date Serviced and + Use | | | | |Needed |what was done + ---------------------------------------------------------------------- + Food | Kitchen |1/6 |120 |4.4 |Clean & Oil; |9/1-Cleaned + Mixer | | | | |cord needs |w/cloth. + Repair | | | | |repair |Oiled w/#10 Oil; + | | | | | |repaired cord + ---------------------------------------------------------------------- + Tool | Farm |1/4 |120 |5.8 |Clear, oiling; |10/6-Cleaned + Grinder | Shop | | | |Have switch |w/vacuum Oiled #10 + | | | | |Have switch |oil. 10/20-Had + | | | | |repaired |switch repaired + ---------------------------------------------------------------------- + Pump |Pump |1/3 |120 |7.2 |Oiling, |9/26-Cleaned + |house | | | |cleaning |w/tire pump; + | | | | | |oiled w/10 oil + ---------------------------------------------------------------------- + + + + +LESSON NO. B-7 + +Credit Points 4 + +READING THE ELECTRIC METER + + +There is no question but what electricity is one of the lowest cost +services in the home and on the farm. A few pennies worth of electricity +will provide the power to run machines that take the place of a man or +of several men working all day. However, we all like to know what things +cost. + +Sometime you may have to decide between different methods--man, horse, +gasoline engine or electric motor power. Then you'll want to know how to +figure the cost of electricity, as well as the cost of the original +equipment. First of all, you should know how to read an electric meter. + + +Reading a Meter + +Electric meters read in kilowatt hours, just as a water meter reads in +gallons and a gas meter in cubic feet. A kilowatt hour is the electrical +energy consumed by 1000 watts of electricity used for one hour. Ten +100-watt light bulbs burning for one hour would use one +kilowatt-hour--one kwh. + +[Illustration: Figure 1. Some meters give the reading directly, like the +mileage total on a speedometer.] + +Some meters are read directly, as shown in Figure 1. The more common +type has four dials which are read from right to left--just the opposite +from the way things are usually read. The hand on the extreme right +turns clockwise, the next hand turns counter-clockwise, the next +clockwise; the last hand on the left turns counter-clockwise. + +The first dial on the right can register up to 10 kilowatt-hours; the +second up to 100 kwh; the third, to 1000 kwh; the fourth, to 10,000 kwh. +After that, the meter starts over again. To take a reading you must read +all four dials of the meter, from right to left. + +[Illustration: Figure 2. Meter dials are read from right to left.] + +To read each dial, you use the number last passed by the dial hand. This +may not be nearest the hand. For instance, if the pointer has passed 6 +and is almost on 7, you read it as 6. Write down the figures in the same +order you read the dial, from right to left. Practice reading the meters +shown in Figure 3 on the following page. + + +What's Your Electric Bill? + +Meters aren't set back each month when the meter reader comes around. +The difference in the readings from one month to the next shows how +many kilowatt-hours have been used. If you know your electric rates, you +can figure your bill by yourself. Your power supplier will furnish you +with a rate schedule on request. + +[Illustration: Figure 3. See if you can read the above correctly. The +answers are shown in a box on the next page.] + +It will be interesting to you to find out how much it costs to operate +the various electric appliances in your home. A sample rate schedule is +shown in Figure 4. + +[Illustration: Figure 4. Sample rate schedule. Note that as the use of +electricity increases, the average cost per kwh is reduced.] + + +Estimating Operating Costs + +To find the cost of operating any single appliance, three steps are +necessary: + +1. Learn the wattage of the appliance. + +2. Estimate how many hours the appliance is used. + +3. Find its operating cost. + + +_To Find Wattage:_ + +Watts, you know, are the measure of electrical power. They are the +product of voltage (pressure) times amperes (rate of flow). Volts times +Amps equals Watts. The nameplate on the appliance will give the voltage +required for proper operation as well as either amperage or watts. If it +gives wattage, you have the information you want. Otherwise you must +multiply volts times amps to get the wattage. When voltage is given as +110-120, use 120 as your voltage. 120 volts is nominal today. + + +_How Much Will You Use?_ + +Now that you know the wattage of the appliance, multiply this figure by +number of hours the equipment operates in one day. Divide this by 1000 +to get the kwh. Now multiply the result by the number of days the +appliance is used each month. This tells you the number of kwh used by +the appliance during the month. + + + |---------------------------------------------| + | | + |Example No. 1 | + |_Yard Light:_ 300-watt lamp | + | | + |Amount of use: 3 hours per night. | + | | + |Multiply lamp wattage times hours of use | + |per night to get watt-hours per night. | + | | + |300 times 3 = 900 watt-hours per night. | + | | + |Divide watt-hours by 1000 to get kwh per | + |night. | + | | + |900 divided by 1000 = .9 kwh per night. | + | | + |Multiply kwh per night times 30 to get kwh | + |per month. | + | | + |.9 times 30 = 27 kwh per month. | + | | + |If the yard light is used 3 hours per night, | + |it consumes 27 kwh per month. | + |---------------------------------------------| + + +Example No. 2 + +_Coffee Maker_: 120 volts, 550 watts (from nameplate) + +Amount of use: 1/2 hour per day. + +Multiply wattage of coffee maker times hours of use per day to get +watt-hours per day. + +550 times 1/2 hour = 275 watt-hours per day. + +Divide watt-hours by 1000 to get kwh per day. + +275 divided by 1000 = .275 kwh per day. + +Multiply kwh per day times 30 to get kwh per month. + +.275 times 30 = 7.250 kwh per month. + +If the coffee maker is used l/2 hour daily, it consumes 7.25 kwh per +month. + + +_Calculate Operating Cost Per Month_ + +Now that you know the number of kilowatt hours an appliance uses, go to +your rate schedule and your electric bill to see what the average kwh +costs. Find the average cost of 1 kwh by dividing the amount of your +bill by the total number of kwh used in a month. + +_Example_: 410 kwh used. $14.35 total monthly bill + +Average cost per kwh equals $14.35 divided by 410 kwh-3-1/2 cents per +kwh. + +Therefore, the cost of operating the coffee maker for a month would be +3-1/2 cents times 7.25 kwh--25.4 or 25 cents. Cost of operating the yard +light would have been 94.5 or 95 cents a month. + + +(a) 6357 (b) 1963 (c) 8996 + +Correct answers to the meter readings shown on the preceding page. + + +Adding Low Cost Helpers + +You can see, by looking at your rate schedule, that the average cost per +kwh gets lower as you use more electricity. To find the cost of +operating additional electrical equipment, the cost per kilowatt hour is +found from the last "step" in the bill--the lowest cost per kwh of the +electricity you're now using. Sometimes power suppliers give special +rates for such equipment as electric water heaters. + + +WHAT TO DO: Find the Cost of Operating Electrical Equipment + +Make and fill in the blanks of a chart showing the electrical equipment +you have and the operating costs per month. + +Make a chart for the home (refer to chart one). Show the probable +operating cost of equipment you might add to what you now have. + + +Demonstrations You Can Give + +Show how to read a meter, making one with plywood or cardboard. Dials +can be painted on the main board. Arrows can be attached so they will +revolve to give different readings. + +Show how to find the wattage of various types of equipment. + +Show how to figure the cost of the average kwh in a home. + + +For Further Information + +Your leader can get additional material for you or you may want to have +someone from your power supplier talk to your club, telling about +meters, how they work and how they are regularly checked for accuracy. + +Chart One-THE HOME + + + Column No. 1. 2. 3. 4. + + Item Wattage Hours KWH per Cost per + Rating Used Month Month + per (col. 1x2)/ (Col. 3 x av. Remarks + Month 1000 kwh cost) + + Electric Iron 1100 30 33 .80 + Stove 880 60 52.8 1.21 (Special + rate) + + + +LESSON NO. B-8 +Credit Points 3 + +IRONING IS FUN WITH THE MODERN HAND IRON + + +When you are getting ready to go to school or to a party, it probably +gives you a good feeling to put on a clean, freshly-ironed skirt, blouse +or dress. But did you ever think about the electric iron that helps so +much to give you that well-dressed feeling? When you were younger, you +may have had a play iron and pretended to iron your doll's dresses. Now +you are old enough to learn about real irons--the different kinds of +irons, how the iron heats, the kind of cord needed, the type of outlet +necessary, how to use safety rules when you iron, and even how to help +with the ironing. + + +Important Things to Know + +There are many different irons, but the two kinds most important for you +to know about now are the regular dry iron and the combination +steam-and-dry iron. + +[Illustration: The thermostat keeps the iron at an even temperature.] + +It isn't weight alone that makes an iron do its job, but the heat of the +iron. The heat is given off in the sole plate. The automatic iron has +what is called a _thermostatic_ control which holds the temperature of the +iron at the heat you want. Some clothes need to be ironed with a very +hot iron, while others need only to be pressed lightly with a cool iron. +The thermostat keeps the iron at an even temperature after you set it +for the heat you want. The thermostat is the heart of the iron. + +Take a look at the iron used in your home. It isn't heavy to lift, and +has a handle that fits your hand easily. It looks graceful and has a +smooth bottom, called the sole plate. And it may have a narrow, pointed +tip which is helpful in ironing pleats, corners and gathers. + +[Illustration: Your iron has a smooth bottom called the sole plate.] + + +The Iron and Safety + +If you are going to learn to do some ironing yourself, the most +important thing for you to remember is SAFETY. You should read all about +the iron first in the instructions which came with it. + +Never use an iron carelessly. Remember the safety rules: + +1. An iron should never be left even for a few minutes without being +disconnected. Turn off by removing the plug from the outlet, or by +turning the control lever to "off." + +[Illustration: Take hold of the plug--not the cord--when you disconnect +it from the outlet.] + +2. Let the iron cool before putting it away. + +3. Wrap the cord carefully around the iron after it is cold. + +4. Always stand the iron where it will not fall off on a child or pet or +your own toes. + +WHAT TO DO: Learn About Your Iron + +Materials Needed: An automatic iron, some old play clothes, towels, +napkins or handkerchiefs, and an ironing board. + + +Steps to Take: + +1. Watch an experienced person iron. + +2. Ask questions about what clothes need to be sprinkled. + +3. Study the thermostat settings on the dial or indicator. + +[Illustration: Most irons have a dial to set for the proper heat for +different fabrics.] + +4. Ask about the kind of fabric each piece of clothing is--cotton, +linen, silk, nylon, etc.--and why the iron should be at high heat for +some, cooler for others. + +5. Set the thermostat for the amount of heat needed, and with an older +person watching you, iron some handkerchiefs, napkins, bath towels, and +a pair of play shorts or blue jeans. + +6. During a month iron some of these articles for your family, keeping a +record of how many you do and what they were. + +7. Take care of your iron. Be responsible for storing it. + + +--------+-----------------+-------------------+---------------------+ + | | No. | | Store Iron Properly | + | Date | Articles Ironed | Type of Article | (check) | + +--------+-----------------+-------------------+---------------------+ + | | | | | + +--------+-----------------+-------------------+---------------------+ + | | | | | + +--------+-----------------+-------------------+---------------------+ + + +IRONING IS FUN + +1. I (use) (do not use) an adjustable ironing Board at home. If I do, I +adjust it to the height that just clears my knees easily as I sit in a +comfortable chair. Yes No + +2. There are three kinds of irons usually used--dry iron, steam iron or +a combination steam or dry iron. I use a ---- iron. + +3. I (have) (do not have) the instruction book. (If you do, read about +the iron.) I know the iron's parts by their correct names. They are----. + +4. I disconnect the iron if I leave it even for only a minute. This is a +safety measure as fires have been known to start from irons left +connected. Yes No + +5. I take hold of the plug--not the cord--when disconnecting the iron. +Yes No + +6. I wait until the iron is cold before wrapping the cord around the +handle and storing the iron because----. + +7. Most irons have a thermostatic control. The iron I am using has +settings for----. + +8. The purpose of the thermostat is----. + +9. These fabrics need high temperature.---- + +These fabrics need medium temperature.---- + +These fabrics need low temperature.---- + +10. These fabrics need sprinkling.---- + +11. The heat and smoothness of the sole plate smoothes the wrinkles. +Pushing down on the handle or moving the iron rapidly only makes ironing +hard work. I will iron slowly and steadily arranging and moving the +garment with the left hand while guiding the iron with the right hand. +(Or the other way for the left handed.) Yes No + +12. I have watched an experienced person iron. Yes No + +13. I have practiced on handkerchiefs, napkins and pillow cases. + +14. Here is my record of ironing for one month. + + + Month ---- + Your Name ---- + + Date I have ironed: + ---------+------------------------------------------------ + | + | + + + +Demonstrations You Can Give + +1. Show a dry iron and a steam-and-dry iron. Tell the difference between +them and when each is to be used. + +2. Display garments that look nice because they have been ironed +properly, and those that have been ironed improperly. Explain about the +heat, thermostat, type of iron and why results differ. + + +For More Information + +At a club meeting ask a parent to give a demonstration of ironing +different articles. Some power suppliers or dealers have people who will +demonstrate the proper way to iron, and how to care for irons. + + + + + +LESSON NO. B-9 +Credit Points 2 + +LET'S BE FRIENDS WITH ELECTRICITY + +Plan a Hazard Hunt + + +Electricity can be your important lifelong friend and helper, so you +will want to know all you can about it and how to treat it properly. +However, careless and improper use of electricity can do a lot of harm. +Used properly, and treated with respect, electricity can do wonderful +things to help you every day in many ways. + +For safe and proper use of electricity, all wiring, fittings, +insulation, cords and plugs must be in good condition. You can be a +detective and track down defects in any such type of electrical +equipment that you may be using in your home or on your farm. + +When you find anything that is wrong, and know where it is, and know +what to do about it, you can very likely correct the condition yourself, +such as replacing a worn extension cord with a new one. If you find +defects in permanent wiring, or some places where wires are bare or +terminals are needed, you should tell your parents about them. + +SAFETY FIRST, remember, should always be on your mind when working with +anything electrical. + + +WHAT TO DO: + + +_1. Have A Hazard Hunt_ + +Go on a Hazard Hunt to see how many electrical hazards you can find. +Look for defects such as broken insulation, worn cords, splices that are +not properly soldered and taped, loose connections, or switches that +aren't working properly. + +There are many ways to have a Hazard Hunt. Choose the method that will +be the most fun. Use the Hazard Hunt Guide in this outline to check your +home, and other buildings. Maybe you'll want to have a friend help check +your home, then you help him check his. Or, why not give each member of +your family a Hazard Hunt Guide and have a contest? Parents may want to +team up against you and other younger members of your family to see +which team can find the most electrical hazards in some set time--say 30 +minutes. + +Have a Hazard Hunt Committee in your club check all member's homes and +buildings and report its findings at the next club meeting. + +_To Make It More Fun_ + +1. Put a hazard tag, like the one shown, (Figure 1) by each hazard that +is found. Leave it until the hazard is corrected. Have another contest +to see which member of the family corrects the most hazards. + +[Illustration: Figure 1] + +2. Report on your Hazard Hunt at the next club meeting. Tell about the +Hazards found, and what you have done or plan to do about them. + +3. Suggest that the entire club have an Electric Hazard Hunt at your +club meeting places or any community building. This could be part of one +meeting. + +4. Have a contest between two teams in the club to see which team can +get the most homes in your community checked by the Hazard Hunt Guide. +Losers could give a party for the winners. + + +_2. Get Others Interested_ + +Promote a community Electric Hazard Hunt. Enlist the support of power +suppliers, electric supply and equipment dealers, schools, newspapers, +radio and television stations. + + +_What To Look For_ + +Make a complete tour of your home and other buildings and see how many +hazards you can locate. When you find a hazard, put a tag near it to +mark it. + + +SAFETY TIPS + +Put hazard tags _near_ the hazard but _not_ directly on broken or frayed +wires, insulators, fittings, or other wiring equipment. Do not touch +them either. Badly-frayed wires should be disconnected immediately from +the power supply. In this way, you will not expose yourself to shock by +accidentally touching an exposed live wire that may be carrying current. + + +4-H Electric Hazard Hunt Guide + +_Wiring and Protective Devices_ + +1. Cable or conduit splices not in boxes---- + +2. Cable or conduit not securely clamped in boxes---- + +3. Conduit or armored cable not properly grounded---- + +4. Cracked or broken insulators (Figure 2)---- + +5. Wire not completely covered with insulation---- + +6. Worn insulation on wire---- + +[Illustration: Figure 2] + +7. Old unused wiring not yet removed---- + +8. Outlets, junction and switch boxes not securely fastened and covers +not in place---- + +9. Switches not working properly (sparks fly as switch is flipped) +(Figure 3)---- + +10. Fuses not of proper ampere rating for circuit---- + +11. Extension cord used in place of permanent wiring---- + +12. Pull chain socket without an insulating link in the chain---- + +13. Pull chain socket near plumbing fixtures or where hands may be wet +or one may stand in water---- + +[Illustration: Figure 3] + +14. No moisture-proof cords for outside weather conditions or heavy +rubber cords for motors and motor driven appliances + + +_Lighting_ + +1. Fixtures in farm buildings installed so that they might be easily +damaged + +2. Lights in haymows and other dusty locations not protected by +dustproof globes + +3. Outside sockets not waterproof + +4. Heat lamps not properly supported by non-current carrying wire, +chains, or brackets (Figure 4) + +5. Light bulbs not frosted, shaded, or placed so that light is diffused +to prevent glare + +[Illustration: Figure 4] + + +_Auxiliary Wiring_ + +1. Outlets overloaded--in other words, "octopus wiring" + +2. Extension cords placed under rugs + +3. Extension cords run through doorways (Figure 5) + +[Illustration: Figure 5] + +4. Extension cords or lamp cords should use underwriters' knot (Figure +6) + +[Illustration: Figure 6] + +5. Plug connections fuzzy (Figure 7) + +[Illustration: Figure 7] + +6. Extension cords run over heaters or radiators + +7. Extension cords, or appliance or lamp cords, worn or frayed + +8. Heating appliances without regular asbestos covered wire + +9. Open sockets or outlets where a baby or small child might stick a +finger or metal toy + +10. Broken plugs (Figure 8)---- + +11. Loose prongs on appliance or lamps plugs---- + +[Illustration: Figure 8] + + +How Many Hazards Did You Find? + +Make a chart listing the hazards, their locations and what you did about +them. Make your own chart and list what you find. + +Demonstrations You Can Give + +Show and tell others how to have a Hazard Hunt. + +For Further Information + +Check with your leader, then ask your power supplier or a local +electrician to tell you about safe electrical wiring, connections and +fixtures. + + +-------------------------+-------------+------------------------+ + |Hazard | Location |What I Did | + +-------------------------+-------------+------------------------+ + |_Loose prong on lamp plug|Living Room |Replaced with new plug_ | + +-------------------------+-------------+------------------------+ + |_Cracked insultor on |Back of house|Notified power _ | + |_service wire in house | |supplier_ | + +-------------------------+-------------+------------------------+ + |_Conduit not securely |Basement by |Notified parents_ | + |_clamped to box |fuse box_ | | + +-------------------------+-------------+------------------------+ + |_Extension cord, old and |Basement, by |Replaced with new_ | + |_worn |washing |rubber-covered one and_ | + | |_machine |protected it from _ | + | | |_water_ | + +-------------------------+-------------+------------------------+ + + + + +LESSON NO. B-10 +Credit Points 3 + +HOW ELECTRIC BELLS WORK--FOR YOU + + +When was the last time you wanted to get a simple message like "You're +wanted on the telephone," "There's someone here to see you," or "There's +a car in the driveway," to someone around your place? Did you have to +walk or run some distance and perhaps shout, too, to be heard by the +other person? Perhaps you had to stop some other work, or interrupt your +favorite kind of fun, to do this bit of messenger work. + +If the nature of the message is like one of those mentioned, and the +number of people in hearing is not too great, then perhaps you can use +bells or buzzers or both to do some of your messenger work for you. Even +though a bell or a buzzer can't talk, it can convey a message. + + +What to Do + +1. Learn how bells and buzzers work, and learn about the many different +kinds. + +2. Plan and install a bell system for your home or farm. + +Bells and Buzzers Can Tell a Lot + +Electric bells and buzzers use the same basic principle as the telegraph +system, invented by Samuel Morse in 1840. Although not as important +today as it was before radio, telephone, and teletype became common, the +telegraph is still in use. + +Bells and buzzers, however, are very common and have many uses. They are +most often seen in the form of doorbells, and rare is the new home that +does not have one or more. Service stations have bell systems to let the +operator know that a car is waiting at the gas pumps. A clock signal +reminds the homemaker when the cooking time is completed. Children are +called to and released from school classes by means of bells and +buzzers. + +Also, various alarms employing bells and buzzers warn us when it's time +to get up, or even that the place is on fire, or that a burglar is +trying to break in! + +Let's find out how bells and buzzers work, what different kinds there +are, the different ways you can control them, and how you can put them +to work for you. + +You'll find that buzzers and bells can help you with your 4-H projects, +and with the proper controls, can be your eyes and voice in a dozen +places at once. + +Why They Buzz or Ring--Electromagnetism + +If we were to look at an electric bell with the cover off, we'd find +that it would be very much like Figure 1. + +A push on the button, which is just a switch that is normally held +"open" or off by means of a spring, sends the current from the battery +or transformer through the circuit. + +[Illustration: Figure 1] + +You will see that the current passes first through two small coils of +wire, and each coil has at its center a piece of soft iron called the +core. When the current is on, the core becomes magnetized and attracts +another piece of iron called the armature with its clapper attached. + +This action rings the bell, but it also breaks the current by pulling +the spring away from the screw on its return to the power supply. + +With the power off, the electromagnet lets the spring return the +armature to its normal position, contact is made again, and the cycle +starts all over again--just as long as you continue to push on the +button. + +Buzzers work exactly the same way, except that they do not have a bell +and depend instead on the vibration of the armature for a noise that's +not as loud or as musical. + +Gongs or chimes, that strike only once when the button is pushed, are +made by connecting the armature with the screw by means of a flexible +wire. + + +A Special Kind of Electricity + +Most buzzers and bells work on a much lower voltage than you normally +find in the wires in your house. Some are made to work at 6 volts, +others at 10 volts, and still others at slightly higher voltages. + +You can get these low voltages by using one or more batteries, or by +using a transformer connected to your house current. Most bells and +buzzers are now powered through transformers. + + +How to Control Them + +The push button is the most common means of control. You can use one +button to control several bells, or several buttons to control one bell, +or have several buttons control several bells. Because low voltage is +used, adding extra buttons is simple, inexpensive, and safe. + +Buzzers and bells can also be controlled by: _clocks_, as in the +interval timer on an electric range or in a school class bell system; +_temperature detectors_, as in a fire alarm or freezer alarm; _door and +window trips_, as in a one-man repair shop or in a burglar alarm; and +_treadles_, as in the driveway of a service station. + +[Illustration: Figure 2] + + +Pick the Right Bell or Buzzer + +Some of the many different types of bells, and various ways of +controlling them are suggested in the table below. Just remember that no +matter what the job or conditions, you can probably find a bell or +buzzer and controls that suit your need. + + +SOME TYPICAL JOBS FOR BELLS & BUZZERS + + -------------------------------------------------------------------- + Number and + Type of location Number and + bell or of bells Type of location + Job buzzer and buzzers control of controls + --------------------------------------------------------------------- + Summon others In the house-- Enough to Push- One at the + to the small to cover all buttons telephone + telephone medium buzzers usual work and each + In locations extension + outbuildings-- phone + medium to + large bells + Outdoors-- + large + weatherproof + bell + All transformer- + powered + --------------------------------------------------------------------- + Notify club Medium to large One may be Hose One--in + member that bell-- enough--if diaphragm the + car is at his transformer- mounted on driveway + produce stand powered the back of ----------------------- + the stand (Complete driveway + including control, + are available, + ready to plug in.) + -------------------------------------------------------------------- + Warn of power Battery-powered One near Relay, One, at + failure to buzzer, medium the held open main + incubator or size poultryman's as long as switch of + brooder bedroom power is on, hatchery + closed by or + spring if brooder + interruption house + occurs + -------------------------------------------------------------------- + Warn of Battery-powered One, in or Temperature One, with + dangerously buzzer, medium near the detector bulb + warm size kitchen (sensitive inside + temperature thermostat) freezer + in freezer + --------------------------------------------------------------------- + + +How to Plan Your System + +To save your time and steps when the telephone rings for someone else in +your family who is some distance away, you can install a simple bell or +buzzer system to summon that person. + +First, you must plan what you are going to do. On a large sheet of +paper, draw to scale (roughly) a plan of your house and grounds, +including those places where phones are located. It will help if you +rule off your paper in 1/8" or 1/4" squares and let each square equal +one foot. Show the location of poles supporting your wiring. + +Next, pick out those areas where you or others would likely be when +someone else would answer the phone and want to call you to it. + +After you have thought about this, and talked it over with members of +your family, show locations on your plan where you think you would like +to have buzzers or bells, and show a button beside each telephone. +(Generally, you should have a bell or buzzer near each phone, also.) + +Figure 3 shows diagrams of various types of systems, and will help you +determine the number of wires you will have to install to connect the +buttons and bells that you have planned. + +Inside, you will connect your transformer and the various buttons and +bells with ordinary indoor bell wire. Outdoors, however, you should use +weatherproof 2-wire or 3-wire telephone twist. + +Show on your plan the distances that must be traversed by each type of +wire, and show the number of conductors in each. Don't overlook the +vertical distances (one floor to another). + +[Illustration: Figure 3] + + +Materials You'll Need + +Because no two situations are just alike, it will be necessary for you +to make your own list of materials. + +As a guide, however, here is a list of typical materials, with the +quantities left blank, for you to fill in as your own requirements and +measurements dictate. + + 10-volt transformer + --- Door buzzers + --- Doorbells + --- Weatherproof outdoor type bells + --- ft. indoor bell wire + --- ft. 2-wire weatherproof telephone twist + --- ft. 3-wire weatherproof telephone twist + --- lbs. staples (insulated) + --- entrance insulators (for attaching + weatherproof to buildings and poles) + +Because your transformer must be wired into your regular house current, +you should have some help on this from an electrician or other qualified +person. Also, you should get that person to review your plans and +materials list before you place an order. + + +Install According to Your Plan + +With the aid of an electrician or other qualified person, install your +transformer, and test it. + +You may then go ahead and complete your signal system, checking +carefully with your plan, and making sure that your installations are +both electrically and mechanically secure. + +Test your system in all possible ways that it might be used. + + +Demonstrations You Can Give + +Build a demonstration board incorporating a farm or home layout, with +pushbuttons or other controls and bells and buzzers appropriately +located. Show and tell how the system would save time and energy. + +Show and tell how some of these work, and their value: power-off alarm, +freezer alarm, fire alarm, driveway alarm. + + +For More Information + +Ask your power supplier or your nearest electrical supply house for +catalogs or literature on various types of signal systems, or ask a +dealer to show you equipment he has in stock. + + + + +LESSON NO. B-11 + +Credit Points 2 + +FIRST AID FOR ELECTRICAL INJURIES + + +What would you do if you saw someone who had been hurt by electricity? + +Did you know that you could save his life, if you had taken the time to +learn and practice a few simple rules of electrical first aid? + +First aid training equips you to know what to do and what not to do for +the injured until medical help can be obtained. While the main benefits +are for you and your family, no one can call himself a good citizen if +he fails to help a stranger who has been hurt. + +The information given here is only for electrical injuries. Perhaps what +you learn will inspire you to take a complete course in first aid. + + +What to Do + +Learn how to prevent electrical accidents, and what to do if an +electrical accident occurs. + +1. Make an electrical hazard hunt in your home or on your farm. Point +out to your parents everything that should be repaired or replaced for +safety's sake. + +2. Read the first aid suggestions that follow. Learn them. + +3. Get to know the six steps that are outlined for mouth-to-mouth rescue +breathing. Practice them on your brother, sister, or parents. Teach the +entire family how to do it. + + +Electricity Can Kill + +In this day of hundreds of uses of electricity, you should know about +electrical dangers. Electrocution can occur from either low voltage +(household type) or high voltage currents. Sometimes household voltages +are more hazardous because people underestimate the dangers involved. + +A fraction of an ampere passing through your heart muscles can be fatal. +Your body offers some resistance to the flow of electricity to ground. +If you are standing on wet ground or in water, or if your skin is damp, +this resistance is greatly reduced. + +Wire cables within walls and cords on appliances are all insulated with +a shock proof covering. Continued use, age, or damage may expose a bare +wire and create a hazard. The point of exposure need be only a fraction +of an inch. Cords are often used and abused. Exposed wires and signs of +wear are danger signals. + +Always be wary of overhead wires. People have been injured or killed +when kite strings, model plane control lines, irrigation pipe, and water +well equipment have come in contact with the power supplier's or their +own overhead wiring. + + +Prevent Accidents + +Underwriters' Laboratories (UL) have taken steps to see that minimum +safety standards are met in the manufacture of electrical equipment. +Look for the UL label when you buy cords or appliances. Never place +cords under carpets or furniture, or drape them over a nail. Replace or +repair worn cords without delay. + +Be especially careful when operating electric devices in the bathroom. +Keep in mind the dangers of a wet floor, grounded metal pipes, and wet +skin. Turning on an AC radio while you are taking a bath is asking for +real trouble. + +There may be shorts in electric devices. Keep your hands dry when using +them, and do not touch them along with grounded metal objects. If you +ever get a slight shock, sound the danger signal and do something about +it. + + +Think, Then Act + +Your first thought in rescuing a victim from an electrical accident +should be your own safety. Speed is also important, because a few +seconds or minutes may save a life. + +The first question you should ask yourself is "Can I quickly turn off +the power?" This would be easier to do in the home than outside. In the +case of a victim trapped in a bathtub from a radio accidentally knocked +into the water, it might mean simply removing the plug from the wall +outlet. If a victim is found grasping shorted, permanently installed +equipment and cannot let go, the main switch might be used for quick +release of the current. + +Outdoors, especially with high tension wires, your danger in rescue is +much greater. To handle the victim, touch him only with a long dry +stick, dry rope, or a long length of dry cloth. Be sure your hands are +dry and that you are standing on a dry board. A broom might be a good +lever to pry a victim from a high tension wire but never use a green +stick containing sap. + + + +First Aid + +Once the rescue has been made and the victim is free of further danger, +check to see if breathing has stopped. If so, start artificial +respiration _immediately_ and send someone for a doctor. + +Artificial respiration must be started as soon as possible after normal +breathing ceases. _Most persons will die within 6 minutes or less if +breathing stops completely unless they are given artificial +respiration._ Precious minutes may have passed before you get to the +victim. Since the victim may be within seconds of death by the time you +are able to touch his body, you should seek to obtain an air flow to and +from the lungs _immediately_. + +The victim may seem stiff as an effect of the current, so don't give up +easily. Continue the procedure for several hours. If transportation is +necessary, remember that there may be internal injury, fractures, or +severe burns. + + +Mouth-To-Mouth Rescue Breathing + +There are various effective ways to give artificial respiration, each +with its advantages and disadvantages. The mouth-to-mouth method is +recommended as a good one to master. It can be used on victims of +drowning, suffocation, and asphyxiation, too. People have been known to +save lives with less exposure to the correct procedure than you are +getting by reading this. So, pay attention and remember what you read. + +Step 1. Turn the victim on his back. Wipe out victim's mouth quickly. +Turn his head to the side. Use your fingers to get rid of mucus, food, +sand, and other matter. + +[Illustration: Head Position] + +Step 2. Straighten victim's head and tilt back so that chin points up. +Push or pull his jaw up into jutting out position to keep his tongue +from blocking air passage. This position is essential for keeping the +air passage open throughout the procedure. + +[Illustration: Push Jaw Up] + +[Illustration: Pinch Nostrils] + +Step 3. Take a deep breath, place your mouth tightly over victim's +mouth, and pinch nostrils closed to prevent air leakage. For a baby, +cover both nose and mouth tightly with your mouth. (Breathing through +handkerchief or cloth placed over victim's mouth or nose will not +greatly affect the exchange of air.) + +[Illustration: Breathe] + +Step 4. Breathe into victim's mouth or nose until you see his chest +rise. (Air may be blown through victim's teeth, even though they may be +clenched.) + +Step 5. Remove your mouth and listen for the sound of returning air. If +there is no air exchange, recheck jaw and head position. If you still do +not get air exchange, turn victim on side and slap him on back between +shoulder blades to dislodge matter that may be in throat. Again, wipe +his mouth to remove foreign matter. + +Step 6. Repeat breathing, removing mouth each time to allow air to +escape. For an adult, breathe about 12 times per minute. For a child, +take relatively shallow breaths, about 20 per minute. Continue until +victim breathes for himself. + + +What Did You Learn? True or False + +1. A broken arm should be splinted before artificial respiration is +applied to a victim who is not breathing. + +2. A person who has been severely shocked with an electric current +should lie down. + +3. A doctor should be called even though you successfully have revived a +victim's breathing. + +4. A fraction of an ampere through the human heart muscles can be fatal. + +5. A copper wire would provide a better path than your body for stray +currents, therefore all appliances should be grounded if possible. + +6. Outside wires are never a hazard because they are covered with +insulation when they are installed. + +7. Cords need not be repaired until you can see bare wires. + +8. Tuning in an AC radio while you are bathing is always dangerous, even +though your hands are dry. + +9. In an emergency, a broom is an acceptable tool for prying a victim +off a high tension wire. + +10. In mouth-to-mouth breathing, an adult's lungs should be filled 12 +times per minute and a child's 20. + + +Demonstrations You Can Give + +Show how to deal with an electrical first aid "problem" given to you by +your leader. + + +For More Information + +Ask your leader to have a first aid expert put on a demonstration. (Many +industrial plants and power suppliers have such people.) + + + + +LESSON NO. B-12 + +Credit Points 3 + +HOW ELECTRICITY HEATS + + +In ancient times, people thought that heat was a material just as air +is. They called it "caloric". When something got warm, they said, +caloric flowed into it. When something cooled off, caloric flowed out of +it. It did not bother them that they could not see caloric. They could +not see air either! + +Now we know that heat is not a material. It does not take up space. It +does not weigh anything. Instead, it is a form of energy. And when we +say that heat is a form of energy, we mean that it can be used to do +work. + + +What to Do + +1. Make a simple resistance heater. + +2. Make some popcorn by: + +(a) conduction (b) convection (c) radiation + + +"Resistance" Makes Heat + +There are at least four ways that electricity can make heat. The one +that we'll cover here is _resistance_ heating. (The others are: +_dielectric_ heating, where the lines of force of an electrostatic field +pass through a non-conductive material and heat it; the _heat pump_, +which is a refrigerator in reverse; and _electronic_ heating, which uses +high frequency waves similar to radio waves to create high speed +movement of the molecules or tiny particles which rub together to make +heat.) + +_Resistance_ heating occurs because every conductor of electricity +opposes the flow of current through it. Some conductors resist more than +others. When they do, a certain amount of warming takes place. The more +resistance that is offered, the more heating there is. + +Some materials, like silver, copper, and aluminum, offer little +resistance. We say they are good conductors. + +Other materials, like iron, offer more resistance. They are still +conductors, but not as good as the others mentioned. + +The _size_ of the conductor, and its _length_ are the other two things +that affect its resistance. The _smaller_ it is, the greater its +resistance. Also, the _longer_ it is, the greater its resistance. +Therefore, when we only want to _move_ electricity from place to place, +we want relatively large, "good" conductors. Here, we do not want to +make heat. In fact, we want to avoid it, because too much heat in the +wrong place can cause a fire. + +But when we want heat, we choose relatively small, "poor" conductors, +and the more heat we want, the longer they must be. If you will think of +the filament inside a lamp bulb; you may recall that it is a very fine +wire, coiled so as to get a maximum length, and made of tungsten which +has a high resistance. + +Because of all these factors, this filament glows at a white heat, and +is a source of both light and heat. + + +Make a Simple Resistance Heater + +_Materials you will need_: + + 1 dry cell battery + 1 foot iron picture wire + Pliers + +Use a short strand of iron picture wire and hook the ends to the +terminals of a dry cell battery. Use pliers so that you do not burn your +fingers. Disconnect the wires as soon as they become hot. Tell why the +wires heat. + + +Conduction is "Touching" Heat + +Conduction occurs when you set a pan containing food right on a heating +element. An egg cooking in a hot frying pan is a good example of +conduction at work. This method is the most efficient single way of +using electric heat for cooking. + + +Convection Depends on Air + +Convection warms food in pans that are not actually touching the heating +element. It uses the hot air around the element to carry heat to the +pan. + +Your oven in your range works by convection. Most houses are warmed in +winter in the same way. The heat produced in a furnace warms the air as +it circulates through. This air in turn keeps your body warm. + + +Radiation is Like the Sun + +Radiation heating is more difficult to explain. It results when heat or +energy waves strike an object and are converted into heat. The energy we +receive from the sun is a good example. When you are wearing dark +clothes on a chilly day, you may become uncomfortably hot. The sunshine +warms you even though the air around you has not been heated. Radiant +energy has a way of being absorbed by dark objects and reflected by +light colored or shiny surfaces. Did you ever notice how snow melts +faster on a black top road than it does on a concrete road? + +The electric heat lamp is one of the most familiar sources of radiant +heat. Other examples are panels and cables that are built into the walls +and ceilings of homes to provide heat. + + +Make Popcorn 3 Ways + +How do you make popcorn? Did you know that you can do this kind of a +heating job three different ways? + + +_Materials Needed_ + + Popcorn + Cooking oil or shortening + Salt and butter + 4-qt. saucepan, with cover. (A glass cover + is preferred.) + Potholder + Electric range + 2 250-watt heatlamps + 2 spring clamp type lampholders + Wire mesh corn popping basket or wire + mesh kitchen strainer (improvise a + screen wire cover) + +_First_, make popcorn the way you usually do. Set a front surface unit +control on the range at "medium high". Pour enough oil to very lightly +cover the bottom of the pan. When the pan is hot, pour in enough popcorn +to cover the bottom with one layer of kernels. Use the potholder in one +hand to hold the cover on, and with the other move the pan back and +forth across the unit. When the popping stops, remove from the heat. + +How did the heat get to the popcorn? + +_Second_, make popcorn in the oven. Add the oil to the pan, cover it and +put it in the oven. Turn the oven on, with the automatic control set at +400 deg. When the oven indicator light goes off, this means that the proper +temperature has been reached. With the potholder, remove the pan and add +one layer of popcorn kernels. Replace the pan in the oven. When the +popping stops (listen for it) remove the pan. + +What kind of heating took place here? + +_Third_, make popcorn with the heat lamps. Clamp the lampholders to the +back of a chair or other vertical support. They should be 6 to 8 inches +apart and pointed directly at each other. Put about 2 tablespoonfuls of +popcorn in the Wire basket or strainer. Do not add oil. Hold the basket +midway between the two lamps. When the popping stops, turn off the +lamps. + +What kind of heating was this? + +Now, butter and salt the popcorn you have made and share it with others. + + +What Did You Learn? + +1. How is heat transferred from one body to another? + +2. Could chicks or pigs receive warmth from a heat lamp without the air +in the pens becoming warm? Explain. + +3. How does a broiler unit in a range cook meat? + +4. How does an oven bake food? + +5. Tell why iron picture wire was used instead of copper wire for your +heating demonstration. + + + + +LESSON NO. B-13 + +Credit Points 2 + +MYSTERIOUS MAGNETISM + + +In ancient times, people found certain rocks that clung together in +bunches. These rocks were very mysterious. People didn't understand them +and many superstitions grew up about lodestones, as these rocks were +called. Lodestone (sometimes spelled loadstone) means leading stone. +People even told Columbus not to sail out of sight of land because a +giant lodestone was just over the horizon waiting to pull all the nails +out of his ships. + +The Chinese were the first to use magnets. They found that if you hung a +lodestone by a string, one end of the stone would always point in the +direction of the North Star. They had the first magnetic compasses. + +An artificial magnet can be made by stroking or gently rubbing a piece +of steel with a lodestone. This piece of steel then can be used to +magnetize another piece of steel. This can be continued on and on. +Lodestones are not always available but you can get the same results +with an electric current. So, magnetism and electricity are very closely +related. + + +What to Do + +Learn about magnetism by doing the experiments that follow. + +Seeing is believing! + + +Materials You Will Need + + + 2 dry cell batteries (#905) + A few feet of No. 18 bell wire + 3 steel knitting needles or similar hard steel + 2 ft. of light thread + Sheet of light cardboard or stiff paper + Permanent magnet (bar or horseshoe) + Compass + 1 or more large nails or spikes + Red and black china-marking pencils or crayons + + Iron filings + Wire cutters + Carpet tacks + + +(Iron filings usually can be found under the grinding wheel in a shop. +If you can't find any, rub some steel wool pads together to produce bits +of metal that will do.) + + +"See" a Magnetic Field + +Cover the permanent magnet with the cardboard or paper. Sprinkle iron +filings on the paper. Tap the paper and note the pattern formed. Strings +or lines of filings pass from one pole of the magnet to the other. The +area covered by the filings is the center of the magnetic field. To +remember this, you might compare the magnetic lines of force that +arrange the iron filings to the contour strips in a farmer's field. + +This magnetic field is one of the important things in our everyday life +with electricity. If it were not for the magnetic field, we would not +have electric motors. Telephones, radios, television, and many other +things we use every day also depend on this magnetic field. + +[Illustration: Figure 1] + + +Make an Electro-Magnet + +You can make magnetism work for you by winding several turns of +insulated wire around one or more large nails or spikes (soft iron). +Connect one end of the wire to the battery. Touch the other end of the +wire to the other terminal for a few seconds and see how many tacks you +can pick up. Repeat the experiment using as many turns as possible. How +many more tacks were you able to pick up? + +[Illustration: Figure 2] + +You have made what we call an electromagnet. When you disconnect the +wire, the nails fall off. This is one of the advantages of an +electromagnet. We can turn magnetism on and off as we wish. Picture a +crane operator throwing the switch and picking up scrap iron and steel. +Then he opens the switch to drop the scrap metals. + +Soft iron can be magnetized easily as you have just seen, but loses its +magnetism in a short time. Steel is harder to magnetize but holds its +magnetism almost indefinitely. + + +Make a Permanent Magnet + +Wrap the insulated bell wire around the steel knitting needle. The wire +should be wrapped the full length of the needle. One end of the wire is +connected to the battery. The other end of the wire is then touched for +just a few seconds to the other terminal. This should make the needle +into a permanent bar magnet. If you did not get results, try two +batteries in series, wind more turns of wire on the needle, and leave it +connected a little longer. Do the same thing with the second knitting +needle. In the same way, you can magnetize a screwdriver, so that you +can use it to pick up and hold steel screws. Don't do it unless you want +your screwdriver to be magnetized. + +[Illustration: Figure 3] + + +See How They Attract and Repel + +Take one of the magnetized needles and hang it with a thread. A thread +stirrup (Figure 4) will help keep it level. Be sure it is not near other +large pieces of steel. Watch the needle. Does it settle down, pointing +in one direction? (Check to see if this is the same direction as your +compass). If it does, you have made a compass. The tip of the needle +pointing north is called the North Pole (North-seeking pole). The other +end is called the South Pole. Mark the North Pole with a stroke of the +red marking pencil. Mark the South Pole black. Do the same thing with +the second needle. You can show this with a sewing needle, and a notched +cork, and a bowl of water. Rest the needle in the notched cork, and +float it on the water. + +[Illustration: Figure 4] + +Hold the compass near the North Pole of the needle. What happens? Does +the South Pole of the needle attract the North or South Pole of the +compass? Try this with the second magnetized needle. See if you can +prove the rule that like poles repel (drive away) and unlike poles +attract. + +[Illustration: Figure 5] + +Connect one end of a wire loop to the battery and run the wire directly +over the compass. Touch the other end of the wire to the battery. Which +way does the compass point now? If you get some motion out of the +compass needle, this proves there is a magnetic field around the wire +when current is flowing. This relation between electricity and magnetism +is the thing that makes electric motors and generators work. + +[Illustration: Figure 6] + + +Make Many From One + +Lay the third needle (unmagnetized) on a table and stroke it with one of +the magnetized needles. (See diagram) Always stroke it in the same +direction. Raise the magnetized needle at least two inches on each +return stroke. Thus you can magnetize the needle by using the other +needle. + +[Illustration: Figure 7] + +Use the wire cutters to cut the first magnetized needle in short +lengths. (Cover the needle with a cloth to keep the pieces from flying.) +Can you show by using the compass that each piece is a complete magnet? +Hold one end, then the other, of each piece to a compass. Does each +piece have both a North Pole and a South Pole? + + +Magnetism and Animals + +The things you have done show that electricity and magnetism are related +in many ways. Magnetism is mysterious, and there are still things to +discover about it. It is thought that animals and birds are aided in +their sense of direction by magnetism. It is commonly known that when a +person gets lost in the woods, he tends to go around in circles. +Possibly this is caused by the earth's magnetic field. + + +What Did You Learn? + +1. Where are natural magnets obtained? + +2. How can artificial magnets be made? + +3. What material is needed for a permanent magnet? For a temporary +magnet? + +4. How can you find out which is the North Pole of an unmarked magnet? + +5. How many poles does a magnet have? + +6. Which magnetic poles attract each other? + +7. Why couldn't you make a compass out of a strip of plastic? + +8. What causes the compass to change direction when a wire carrying +battery current is held over the needle? + +9. List the materials you would need and tell how you would build a +homemade compass. + +10. Tell what you enjoyed most about becoming acquainted with mysterious +magnetism. + + + + +LESSON NO. B-14 + +Credit Points 2 + +Give your appliances and lights a square meal + + +Would you say that having enough to eat was pretty important in the home +that you know? + +The "food" for your appliances and lights is electricity, and like you +they must be "fed" enough. + + +What to Do + +1. List the appliances and lights in your home. + +2. See if any of them are "starving" for the electricity they need. + +3. Learn how the electricity gets to where it's used. + +4. Make a chart of the electrical circuits in your home. + +5. Make sure that each circuit is protected with the right fuse or +circuit breaker. + + +Count Your Electrical Blessings + +Many people in much of the rest of the world wish that they could trade +places with us, because we have so many electrical appliances in our +homes. + +Of course, we have not always had as many appliances as there are today. +When electricity first came along, people used it only for lights. Then, +they began to add flatirons, washing machines, refrigerators, coffee +percolators, and radios. + +Then more and more electrical things were made for people to use and +enjoy. Now we have dozens and dozens of uses for electricity in our +homes. + +How many different uses for electricity are there in your home today? +Ask your parents how many there were when your home was built or first +wired. How many were _common_ when your parents began to keep house? + + +Some Homes Are Behind Times + +Many older homes were built before electricity was available, and were +wired later. And like them, some older homes that were wired as they +were built had only enough wiring for lights and a few other appliances, +because those were the only uses that were known at that time. + +But people kept on living in these homes, and kept adding to the uses +they made of electricity without adding to their wiring. + +What has this meant? Well, if electricity were like cars and trucks, you +could say that some people are trying to put turnpike traffic through a +back-country dirt road! + + +Watch for Signs of Starvation + +Of course, as your state has done with its highways, some people have +expanded and modernized their wiring. But many others have not yet seen +this need, or if they have, they may have to do it again. + +Here's why: + +Your power supplier delivers current to you at the right voltage or +electrical pressure. If the wires in your house are large enough, they +will pass this full voltage on to the appliances. + +But if your wiring is too small, the electricity arrives at the +appliances so weak that they can't work properly, and much of what you +pay for is wasted. + +Here are some things you can watch for in your own home. They will tell +you whether your appliances are getting enough electrical "food" or not. + +1. _A shrinking TV picture_--If it draws in from the sides of the +screen, fades, loses contrast, or if the sound becomes distorted, you +may have low voltage. + +2. _Too much fuse blowing or circuit breaker tripping._ + +3. _Heating appliances are slow to do their jobs._ + +4. _Lights dimming_, when motors or other appliances are turned on. + + +There Should Be Enough Ways to Get "Appliance-Food" Around + +If appliances in your home show these starvation signs, then you may not +have enough ways for the electricity to get to where it's used. + +There are three kinds of these electrical highways or circuits, and your +home should have enough of each: + +1. _General purpose circuits_--These serve lights all over the house, +and convenience outlets everywhere except in the kitchen, laundry, and +dining areas. + +A rule-of-thumb is: There should be at least one general purpose circuit +for each 500 sq. ft. of floor space. + +2. _Small appliance circuits_--These are not used for lights, but +instead they supply convenience outlets in the kitchen, laundry, and +dining areas where portable appliances are most used. + +Every home should have at least two small-appliance circuits. + +3. _Individual or special-purpose circuits_--One of these is needed for +each: electric range, dishwasher, water heater, freezer, automatic +washer, clothes dryer, air conditioner, pump, and house heating +equipment. + + +----------+------+------+------+------+-------+ + | | | | | | | + | Actual | | | | | | + | Size | | | | | | + +----------+------+------+------+------+-------+ + | Gauge | | | | | | + | Size | 14 | 12 | 10 | 8 | 6 | + +----------+------+------+------+------+-------+ + | Fuse or | | | | | | + | Breaker | 15 | 20 | 30 | 40 | 55 | + +----------+------+------+------+------+-------+ + |Max. Watts| | | | | | + |at 115 V. | 1725 | 2300 | 3450 | 4600 | 6325 | + +----------+------+------+------+------+-------+ + |Max. Watts| | | | | | + |at 230 V. | 3450 | 4600 | 6900 | 9200 | 12750 | + +----------+------+------+------+------+-------+ + +[Illustration: Wire sizes commonly used in homes] + + +Each Circuit Big Enough + +The capacity of each circuit is limited by the size of its wires. The +chart above shows you the actual sizes of wires commonly used in +permanent home wiring, and what each will carry. Notice that each size +is given a number, and the smaller the number, the bigger the wire. + +Also notice that a given size of wire will carry twice as many watts at +230 volts as it will at 115 volts. (Watts are figured by multiplying +amps times volts.) + +General purpose circuits usually are either Number 14 or Number 12 wire, +at 115 volts. What is the capacity of each, in watts? (Number 12 wire is +recommended for all new general purpose circuits.) + +Small appliance circuits are required to be at least Number 12 wire. + +Individual circuits are always sized according to the appliance they +serve. Find the size wire that should be used for a 10, 000-watt, +230-volt range; a 1500-watt, 115-volt dishwasher; a 4500-watt, 230-volt +clothes dryer. ________ ________ ________ + + +Only One Fuse Size Right + +A fuse in an electrical circuit is like an alert traffic +policeman--stopping everything if there's danger. A circuit breaker +serves the same purpose, and the right size is installed when the wiring +is done. + +A policeman uses his brain to tell him when to blow his whistle, but a +fuse depends on the size of the little fusible (meltable) metal link +that you see under the glass. + +If too great an electrical load is added to a circuit, this link will +melt and prevent a dangerous overload. If you put in a fuse with too +heavy a link, it will not melt in time, and the wiring and equipment may +be damaged. + +Therefore the right size of fuse is very important, and is something +that you should check in your own home. + +See the chart above for the right fuse for each size wire. + + +Make a Circuit Chart + +At one or more places in your home there is a box or panel containing +the fuses or breakers for the various circuits. Attached to the inside +of the door of each such panel should be a chart something like this: + +[Illustration] + + +-----+---------------------+-----------+ + | No. | Description | Fuse size | + +-----+---------------------+-----------+ + | 1 | Range | 40 | + +-----+---------------------+-----------+ + | 2 | Kitchen Outlets | 20 | + +-----+---------------------+-----------+ + | 3 | Dining Room Outlets | 20 | + +-----+---------------------+-----------+ + | 4 | Living Room Outlets | 15 | + +-----+---------------------+-----------+ + | | | | + +-----+---------------------+-----------+ + | | | | + +-----+---------------------+-----------+ + +Notice that in our chart we have made columns for a description of what +each circuit serves, its number or position in the panel, and the proper +size fuse for it. + +Because most such charts leave out this last very important bit of +information, you should make a complete new chart, like the one shown. +Provide as many lines as there are fuse positions. Paste or tape it to +the inside of the panel door. + +Then, ask permission of your parents to disconnect all the circuits by +unscrewing the fuses or flipping the circuit breakers. _Do not touch +anything but the fuse rim._ Then reconnect them, one at a time, to find +out what each circuit serves. Turn on as many lights as you can, to help +you in your detective work. Use a test lamp at those outlets that do not +have a light connected to them. Write two or three words describing each +circuit on the proper line on your chart. + +On a separate sheet, keep track of the appliances and lights that are on +each circuit, and add up the watts. (If the name-plate of any appliance +gives "amperes", "amps", or "A" instead of watts, just remember that +amps times volts equals watts.) This will tell you if any of them are +overloaded. Show this sheet to your parents. + + +Check the Wire Sizes + +_Disconnect the main switch_, and determine the size of the wires in +each circuit. Don't include the insulation in your measurement. + + +_BE CAREFUL! + +Even though you have disconnected the main switch, the wires coming into +it are still "live". So, do not touch any wires. Instead hold the wire +size chart near them so that you can tell which gauge each one is._ + +Write in the proper size fuse for each circuit on your chart. + + +Replace Any Wrong-Size Fuses + +Do the fuse sizes you have written on your chart agree with the ones +that are in place in the panel? + +Get the right size fuses and replace any that are wrong. Make sure that +you have a reserve supply of the right sizes, and that they are handy +for future use. + + +Talk it Over With Your Parents + +Do you think that your home has enough of the proper size circuits? If +not, talk it over with your parents. They may want to ask an electrician +to go over the wiring and make the necessary changes. + + +What Did You Learn? + +(Underline the right answer.) + +1. A (television set, radio) is very sensitive to changes in voltage. + +2. Dimming lights mean (static in the wires, an electrical overload). + +3. Wires that become warm from overload make it (more expensive, +cheaper) to operate the equipment. + +4. A home of 2,000 sq. ft. should have at least (three, four) general +purpose circuits. + +5. One solution to low voltage symptoms is (heavier fuses, more +circuits). + +6. Full capacity for a Number 14 wire circuit at 115 volts is (1725 +watts, 3000 watts). + +7. A room air conditioner should be on (a general purpose, an +individual) circuit. + +8. The purpose of a fuse is to (let you disconnect the circuit, +automatically prevent overloading the circuit). + +9. The right size fuse is determined by (wire size, the store where you +buy it). + +10. A circuit chart should give (circuit description and fuse size, the +maker's name). + + +Demonstrations You Can Give + +Ask your leader to help you plan a demonstration. You can show how +lights dim when too many other appliances are connected, how a fuse +protects against overloading, and the danger of using too large a fuse. + + +For More Information + +Ask your Extension agent, power supplier, or electrician for additional +help. + + + + +LESSON NO. B-15 + +Credit Points 4 + +YOU CAN MEASURE ELECTRICITY + + +Instruments that can detect or measure the flow of electricity have +helped to make possible the wonders of electricity as we know them +today. + +Scientists in laboratories must have measuring devices for experiments +leading to new uses of electricity. Power suppliers must have +instruments that tell what the generating equipment is doing and to +measure the amount of electricity being sold to users. Factories need +instruments that keep tab on electrical equipment to make sure +electricity is being used efficiently. + +In fact, almost anywhere you find electric power at work you'll find +electrical instruments--even in your home. The one you know best +measures the amount of electricity used. Another, in the family car, +shows whether the generator is charging the battery or if the battery is +discharging. + + +What to Do + +1. Make a simple kind of direct-current meter that will show you that +there's a magnetic field around a wire carrying an electric current and +that will detect a very tiny current. + +2. Make a more refined D.C. instrument (galvanoscope) and measure the +voltage of different sizes of dry batteries, and show how an electric +current can be induced. + + +Tools and Materials You'll Need: + + Pair of pliers, knife, small hammer + 30 feet of No. 24 bell or magnet wire + Compass + Two coins--a penny and a dime + Fine sandpaper + Blotting paper + Plastic or cellophane tape + Wooden blocks (See Figure 4) + Glue + 2 small nails + One #905 dry cell, a penlight battery, and + two regular flashlight batteries + Table salt + Drinking glass + 2 paper clips + Two machine bolts + + +How They Work + +Like many electrical things, most electrical instruments depend on the +action of magnetism created by an electric current. There is a magnetic +_field_ or lines of force around any wire carrying an electric current. +If this field is controlled and made to react on a sensitive device, +like an easily moved pointer, we have an electrical instrument. + + +Detect a Magnetic Field + +First, let's prove that there is a magnetic field around any wire +carrying an electric current. Take a piece of wire about two feet long +and scrape off about an inch of insulation from each end. Connect one +end to a battery terminal. Make a loop of wire that crosses the face of +your compass, north to south. Now touch the other end of the wire to the +other battery terminal. + +(DO NOT attempt to substitute alternating current, as from a model +railroad transformer because its alternating current will cause the +compass needle to swing rapidly from one side to the other.) + +[Illustration: Figure 1. + +Put your right hand beneath the wire so that your fingers point the way +the needle deflects, and your thumb will point in the direction that the +current is flowing.] + +What happens? Your compass needle should move to one side because it is +very sensitive to magnetic influences. This proved that the wire created +a magnetic field or lines of force when we passed electricity through +it. (Figure 1) + + +Detect a Tiny Current + +How sensitive is your simple electric meter? Take about five feet of +wire and wrap it around your compass as in Figure 2, keeping the turns +bunched together as much as you can. Leave about six inches at both ends +of the wire extended for leads. Scrape the insulation off the last inch +of both. Rotate the coil and compass until the needle and coil are +parallel, both pointing north and south. + +[Illustration: Figure 2] + +Take a copper penny and a dime, and clean off any corrosion or film on +the coin faces with a bit of fine sandpaper. Now take a piece of +blotting paper about the size of the penny and dip it into strong salt +water. Place the damp blotting paper between the penny and the dime. +Place one of your compass coil leads against the dime, and the other +against the penny as shown in Figure 3. Be sure you have good +metal-to-metal contact between the wires and the coins. + +[Illustration: Figure 3] + +At the instant that you squeeze the leads against the coins, watch what +is happening to the compass needle. It should move for an instant from +the north position each time you press the leads against the two coins. + +Obviously, the little coin battery you have just made produces a very +weak electrical current. Even so, your instrument should be able to +detect it. + + +Make a Simple Galvanoscope + +Now let's make a meter that is a little more practical to use. Broadly +speaking, a galvanoscope is an instrument that detects the presence of +electric currents. It sounds complicated but it is really quite simple. +It is named in honor of an Italian professor named Galvani who made +important early experiments with electricity. + +A refinement of the galvanoscope is today's galvanometer. Other related +instruments are the voltmeter and ammeter. These are very important +instruments to the electrical engineer. + +Using a glass or anything three to four inches in diameter, wind about +20 turns of wire in a "bunched" coil as in Figure 4. Wrap the coil at +several points with cellophane or plastic tape to keep it from +unwinding. + +[Illustration: Figure 4] + +Make a wood base for your coil as shown in Figure 4. The compass support +blocks can be thin wood slats. Do not attach them with steel nails or +tacks. Use glue instead. Hold the coil in the slot between the blocks +with glue or melted wax or use copper staples. Place the compass on the +supports and rotate the base so that the compass needle and coil are +parallel, pointing north and south. + + +Measure the Voltage of Batteries + +Do you know what difference the size of dry cell battery makes in the +voltage it supplies? Your meter can tell you. + +To test the voltage of batteries we must be able to control our +galvanoscope. To do this, connect a glass of strong salt water in series +with the battery as shown in Figure 5. Make sure the wire ends immersed +in the salt water are scraped free of enamel. + +[Illustration: Figure 5] + +With one of the batteries connected, move the wires in the salt water +first closer, then farther apart (keeping them parallel to each other) +while watching your compass needle. When the needle stays 15 to 20 +degrees off north, lock the wires in the salt solution in place with +paper clips. + +Now disconnect the battery you have been using and connect a smaller +battery. If both batteries are fresh, the compass needle should return +to almost the same spot. This proves that both batteries regardless of +size put out the very same voltage. The larger ones, however, are +designed to last longer. + + +Measure the Difference between Series and Parallel + +Using the salt solution as in the previous experiment, connect two +flashlight batteries in series as shown in Figure 6. The compass needle +should move about twice as far as it did with one battery connected. +This shows that when you connect batteries this way you double their +voltage. + +[Illustration: Figure 6] + +Now place your batteries side by side and connect the two top terminals +and the two bases as shown in Figure 7. The compass needle should move +only as much as it did for one battery. This is called a parallel +connection. You can see that this arrangement does not double the +voltage, even though you used two batteries. + +[Illustration: Figure 7] + +While you have this hookup, try reversing the position of the leads +connected to your batteries. Notice that reversing the direction of +current flow in the coil causes the compass needle to swing in the +opposite direction. + + +Test for Induced Current + +Make a simple coil by winding about 50 turns of wire around a machine +bolt core. The bolt should be 1/4 to 1/2" in diameter and about two +inches long. Connect the coil to your galvanoscope as shown in Figure 8. +Pass the coil back and forth close to the end of a permanent magnet. +[Illustration: Figure 8] + +Notice a slight deflection of the compass needle with each pass. You +have shown that electricity can be induced in a wire coil by moving it +through a magnetic field. Currents generated in this way are called +induced currents. + +[Illustration: Figure 9] + +Now make another coil and core just like the first one and arrange them +and a connection as shown in Figure 9. If you make and break the current +to the second coil, you will build up and collapse a magnetic field +around the first coil and again induce a current in it. You will see the +compass needle swing back and forth again. + +These last two experiments give you a crude idea of how an electric +generator works, producing electric current by induction as a coil-wound +rotor revolves within a magnetic field. + + +What Did You Learn? + +What does every current-carrying wire have around it? How does this help +us to measure electricity? How sensitive are electrical instruments? +What is the difference in voltage between (a) a large and a small dry +cell? (b) batteries connected in series and in parallel? (c) your +original connection and the reverse of it? What similarity does the test +for induced current show between movement through a magnetic field and +the making and breaking of a direct current? + + +Demonstrations You Can Give + +Show others how your galvanoscope can detect: whether a battery is +producing current, which way the current is flowing, and whether a +current is strong or weak. Demonstrate how a current can be generated +using magnetism. + + +For More Information + +Ask your power supplier representative to show you some of the +instruments used by his organization, and to give you a brief +explanation of how they work. Ask him or an electrician to give you a +demonstration of a split-core ammeter. + + + +***END OF THE PROJECT GUTENBERG EBOOK ELECTRICITY FOR THE 4-H SCIENTIST*** + + +******* This file should be named 38036.txt or 38036.zip ******* + + +This and all associated files of various formats will be found in: +http://www.gutenberg.org/dirs/3/8/0/3/38036 + + + +Updated editions will replace the previous one--the old editions +will be renamed. + +Creating the works from public domain print editions means that no +one owns a United States copyright in these works, so the Foundation +(and you!) can copy and distribute it in the United States without +permission and without paying copyright royalties. Special rules, +set forth in the General Terms of Use part of this license, apply to +copying and distributing Project Gutenberg-tm electronic works to +protect the PROJECT GUTENBERG-tm concept and trademark. 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