Electricity for the 4-H Scientist

Part 1

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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.

Part 2

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.

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