1. Ch. 5: Electricity and Magnetism

2. Electricity All matter is made up of atoms. Within each atom are positive and negative charges. A proton carries a positive charge. An electron carries a negative charge. If a substance loses electrons, it become positive. If a substance gains electrons, it becomes negative.

3. Attraction and Repulsion Two substances carrying the same charge repel one another. Two substances carrying opposite charges will attract one another.

4. Ex. Two charged balloons are suspended from the ceiling. If balloon A carries a positive charge, what can you determine about the charge of balloon B? A B

5. Ex. Determine the type of interaction (attract or repel) between balloon C and balloon D. A B B C A D

6. Conductors and Insulators In order to become charged, a substance has to be able to allow charges to move through it. A conductor allows charges to flow from one point to another. An insulator prevents charges from moving.

7. Static Electricity When excess charges are at rest this is described as static electricity. There are 3 different ways of creating static electricity.

8. 1.Charging by Friction When two neutral objects are rubbed against one another, there will be a transfer of electrons. The direction of the transfer is determined by the triboelectric series. (Substances at the top of the series acquire the negative charge.)

9. Ex. Use the triboelectric series to determine the charges on each object. (a.) Plastic ruler and Wool cloth (b.) Cotton sheet and Nickel rod Triboelectric Series Plastic Gold Nickel Cotton Paper Wool

10. 2.Charging by Conduction If a neutral object touches a charged object, then it will acquire the same charge.

11. 3.Charging by Induction When a charged object comes close to a neutral object, the neutral object will accumulate the opposite charge on its surface. This will result in the two objects becoming attracted to one another.

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