### Electricity and Magnetism SOL 4.3

The student will investigate and understand the characteristics of electricity. Key concepts include: a) conductors and insulators; b) basic circuits (open/closed, parallel/series); c) static electricity; d) the ability of electrical energy to be transformed into heat, light, and mechanical energy; e) simple electromagnets and magnetism; and f) historical contributions in understanding electricity.

Reference: Textbook pages F66-F100 Chapter 13

*Also see www.spellingcity.com Type in teacher name: Beverly Murray

Vocabulary:

1. lightning- a discharge of static electricity from a huge cloud called a thundercloud

2. electrical energy- related to the movement of charged particles. It can come from batteries. Most electrical energy comes from power plants that burn fuels to make electricity that can be sent through wires to homes and businesses.

3. static electricity- the build up of electrical charge on a material. Static electricity does not flow

4. current electricity- the electricity that flows through a circuit; a moving electrical charge

5. ammeter- an instrument used to measure amps

6. amperes- (amps) the unit used to measure the number of electrical charges that flow past a certain point in one second

7. circuit- the path that electricity can move through (page F78)

8. generator- a device that creates alternating current by spinning an electric coil between the poles of a powerful magnet.

9. switch- a device that controls the current in a circuit; it can open or close an electric circuit

10. fuse- a device that keeps too much electricity from flowing through wires

11. circuit breaker- a reusable switch that protects circuits from dangerously high currents

12. conductor- a material through which heat or electricity flows easily

13. insulator- a material through which electricity does not flow easily

14. closed circuit- a circuit with no gaps or breaks in the path (a complete path so current electricity will flow through the path)

15. open circuit- a circuit with gaps and breaks (an incomplete path so current electricity will not flow through)

16. series circuit- a type of circuit in which electricity can flow in only one way; a single path (page F82)

17. parallel circuit- a type of circuit in which electricity can flow in two ways (page F83) each object is connected to the cell separately

18. positive- a positive electrical charge is a plus sign (+) (opposite charges +/- attract each other)

19. negative- a negative electrical charge is a minus sign (-) (like charges +/+ or -/- repel each other)

20. dry cell- a battery that changes chemical energy into electrical energy. (page F81)

21. wet cell- a device that produces electricity using two different metal bars placed in an acid (liquid) solution.

22. electrode- the positive or negative terminal of a wet cell.

23. magnet- a material or object that produces a magnetic field (magnetic)

24. magnetic field- a region of magnetic force around a magnet

25. poles- one of two ends of a magnet; every magnet has two poles (north and south). The pull of the magnet is strongest at the poles. A compass is a magnet. The Earth is a giant magnet.

26. electromagnet- a temporary magnet created when current flows through wire wrapped in coils around an iron bar (a battery can be used as the electricity source for an electromagnet). It is a magnet made with electricity.

27. permanent magnet- a magnet that keeps and does not loose magnetism

28. temporary magnet- a magnet that eventually looses magnetism

Study Guide Electricity and Magnetism SOL 4.3

Kinds of Circuits:

closed circuit       open circuit                closed circuit              parallel circuit

 Series Parallel Connection both bulbs are on the same circuit Each bulb is on a separate circuit Removing one bulb both bulbs go off Only the removed bulb goes off Brightness dim bright

Conductors:                              Insulators:

metals                                      rubber, plastic, wood

Historical contributions to electricity:

Benjamin Franklin- a curious and inventive thinker. In 1752, he used a key tied to a wet string from a kite during a thunderstorm to prove that lightning was a form of electricity. He discovered the lightning rod which protected buildings and ships from lightning damage.

Michael Faraday- a British physicist and chemist that studied the nature of electricity and the magnetic field around a conductor. He discovered electromagnetic induction, the electric motor, the transformer, and generator in the mid 1800’s. He followed in the footsteps of Ben Franklin.

Thomas Edison- In 1879, invented a long-lasting light bulb. He built the first power plant.

Magnets:

-Magnets come in all sizes and shapes.

-They are found in a rock called magnetite.

-Magnets have two poles- North and South

-Like poles repel. N/N or S/S

-Unlike (opposite) poles attract. N/S

-Magnets have the strongest pull at the poles.

-Magnets attract things made with iron, nickel, or cobalt.

-A compass is a magnet. The magnetic needle inside points towards Earth’s North Pole.

-Earth is a large magnet.

-Used on cabinets, in can openers, or to post messages on a refrigerator

-Many animals use earth’s magnetic field to find their way around. It’s as if they have their own built-in compass. Animals use this compass to navigate thousands of miles between their nesting areas and winter habitats. (example: migrating birds, sea turtles, dolphins, whales)

Electromagnets:

-Electromagnets can be powerful.

-They attract iron, steel, nickel, and cobalt.

-Doctors use electromagnets to remove iron splinters from patients.

-Recyclers use them to separate scrap metals.

-Electromagnets are used in machines such as tape players, bells, motors, buzzers, loud speakers, garbage disposals, garage doors, ceiling fans, computers, videotapes, hair dryers, telephones, headphones, stereo speakers, microwave ovens, credit cards, clothes washers and dryers, and televisions.

-They are used in a motor to make mechanical energy.

*Did you know that the electric eel can generate up to 500 volts of electricity and that the electric ray can put out about 220 volts?

*Did you know that you are electric, too? Your heart muscle makes electricity. An EKG or ECG (electrocardiogram) is a test to measure the electrical pulse created when a heart beats. Your brain sends millions of tiny pulses of electricity up and down your nerves every second. The signals send and receive information to help your body function or to warn your body of a problem.

Magnetism and electricity are natural energy forms that have existed since the beginning of time. We cannot see, hear, or smell the force of electricity or magnetism. They are both useful, powerful forces. These two great forces make our life easier!