Electricity, Magnetism,
and Electromagnetism
and Electromagnetism
Science Study Guides
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Electricity, Magnetism,
and Electromagnetism |
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Magnetism
| magnet | An object that attracts metals such as iron and steel. | |
| magnetic field | The space around a magnet in which a magnetic force can be found. | |
| pole | The end of a magnet. | |
| attract | To pull toward one another, as opposite poles of two magnets pull toward one another. | |
| repel | To push away, as similar poles of two magnets push away from each other. | |
| compass | An instrument that uses a freely moving magnetic needle to indicate direction. | |
| lodestone | A form of the mineral magnetize that is naturally magnetic or has become magnetized. |
Notes:
What makes a magnet magnetic?
Most magnets are made of iron. The particles
that make up iron are like tiny magnets. In a normal piece of iron the particles
are all mixed up. They point in different directions. In a magnetized piece
of iron the particles point in the same direction.
Electricity
| electricity |
A form of energy that can produce light, heat, and magnetism. |
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| static electricity | A kind of electricity made by friction. Positive and negative charges that are separated from each other and are not moving. | |
| current electricity | A kind of electricity produced when negative charges move along a path. | |
| circuit | The path along which negative charges move. | |
| complete circuit | A circuit whose path is not broken. | |
| incomplete circuit | A circuit whose path is broken. | |
| filament | The material in a light bulb (usually a thin wire) that glows when heated by an electric current. | |
| terminals | A device for making an electrical connection. | |
| lightning | A flash of light caused by a discharge of static electricity between two clouds or from a cloud to the Earth. |
Making Electricity
| battery |
An object that changes chemical energy into electricity. |
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| generator | A machine that uses a magnet to make electricity. | |
| dry cell battery | A battery made of a zinc case, a carbon rod, and a chemical paste. | |
| wet cell battery | A battery made of lead, water, and acid. |
Electromagnetism
| electromagnet | A piece of iron that becomes a temporary magnet when electricity flows through an insulted wire wrapped around it. |
Scientists
| Benjamin Franklin |
Conducted early experiments with electricity. |
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| Thomas Edison | Invented the first incandescent lamp, the phonograph, and many inventions that used electricity. | |
| Lewis Howard Latimer | An American engineer and inventor who was a a member of the Edison Pioneers. | |
| Michael Faraday | An inventor who discovered that magnetism can create electricity, and electricity can create magnetism. | |
| Samuel Morse | Invented the telegraph machine and the code used to send messages. | |
| patent | A document granting the right to take credit for an invention. |
Questions For Study
1. What kind of electricity is caused by friction?
Static Electricity is caused by friction.
2. How are charged particles in matter affected when two objects are rubbed
together?
All matter is made up of tiny particles that have electric charges. Some of these particles have a positive charge. Other particles have a negative charge. Rubbing two objects together may cause some of the negative charges to rub off one object. The charges move to the second object. This gives the second object a greater negative charge than the first object.
3. How is current electricity produced?
Current electricity is produced when negative charges move along a path.
4. What is a circuit? What are the parts of a circuit?
A circuit is the path along which negative charges move.
There are four parts to a circuit:
(1) There is a source of electricity Example: A battery
(2) There is a path along which charges can move. Example: A wire
(3) There is a switch that opens and closes the circuit. Example: A knife
switch
(4) There is some object that uses the electricity. Example: A light
bulb
5. Explain the difference between a complete circuit and an incomplete circuit.
When a switch is closed or turned on, the path of electricity is complete. The charges move. A circuit whose path is complete is called a complete circuit. When the switch is open, or turned off, the path is broken. The movement of charges stops. The path is incomplete. A circuit whose path is incomplete is called an incomplete circuit.
6. Explain how electricity is produced in a flashlight.
A dry cell battery is the source of electricity in a flashlight.
7. What are the three ways to make electricity?
Electricity can be made from chemical energy in dry cell batteries and wet cell batteries, and from mechanical energy in generators.
8. How is energy produced in a hydroelectric power plant?
A generator is a machine that uses a magnet to produce electricity. Power plants use large generators to make electricity for whole towns. Generators have moving parts. They need a source of energy to move the parts. Generators usually use fossil fuels, water, wind, or nuclear generated power.
9. What would show the magnetic field of a magnet?
A magnetic field may can be seen when iron filings are sprinkled near a magnet. The iron filings form a pattern of lines. These lines are called lines of force. Lines of force show where the magnetic field is and what it looks like.
10. Explain the difference between the two poles of a magnet.
The ends of a magnet are called the poles. A magnetic field is strongest at the poles. A magnet has two poles - a north pole and a south pole. The poles are equal in strength.
The north pole of one magnet attracts the south pole of another magnet. The south pole of one magnet attracts the north pole of another magnet. But the north pole of one magnet repels, or pushes away, the north pole of another magnet. In the same way, the south pole of one magnet repels the south pole of a second magnet.
11. How are particles in magnetized iron different from those in unmagnetized
iron?
Most magnets are made of iron. The particles that make up iron are like tiny magnets. In a normal piece of iron the particles are all mixed up. They point in different directions. In a magnetized piece of iron the particles point in the same direction.
12. How is magnetism used to produce electricity?
Magnetism can be used to produce electricity. This can be done by moving a magnet through a coil of wire. Electricity is produces as long as the magnet moves through the coil. A generator produces electricity this way.
13. What are some uses of electromagnets?'
Electromagnets are often used in scrapyards to lift metal and move it. Many electromagnets are strong enough to lift heavy objects, such as cars. Electromagnets are also used in telephones.
Websites for Magnets and Magnetism
