1. January 13, 2010
charge

2. Last time we created top and bottom “types” of tapes.
Two TOP tapes will:
A. Attract
B. Repel
C. Might do either.

3. two bottom tapes will
attract
repel
ignore each other

4. a top tape and a bottom tape will
attract
repel
not interact

5. when two “charged” tapes move together-
the interaction increases
the interaction decreases
the interaction does not depend on the distance.

6. how many types of charge have you observed?
one
two
three
four

7. Could there be a third kind of charge?
Yes No
Not Sure
Let’s think about this.

8. Weird Science Type 1 (+) Type II (-) Type III () R A Type 1 (+)

9. From whence this charge???
Easily Removed - +

12. The electric charge on an electron is very small and it is NEGATIVE: -1.6 x Coulombs. The protons found at the center of atoms have the same amount of charge as the electron except it is a POSITIVE electric charge: +1.6 x Coulomb

13. Materials Two kinds of materials: Insulators Conductors
Electrons and Protons are tightly bound to their positions. Hard to move them around.
Conductors
Electrons are easily removed and moved around.
Electrons are said to be MOBILE charges.
There are other kinds of materials that we will not discuss: semiconductors, semi-metals

14. Review: Ways to charge an object
Rubbing or bond breaking (same thing)
Transfer
Direct transfer
Polarization
Induction
??????

15. Same as before: Polarization

16. The Triboelectric Series
When two of the following materials are rubbed together under ordinary circumstances, the top listed material becomes positively charged and the lower listed material becomes negatively charged. MORE POSITIVE rabbit's fur glass mica nylon wool cat's fur silk paper cotton wood acrylic cellophane tape polystyrene polyethylene rubber balloon saran wrap MORE NEGATIVE
No! No!
No! No!

17. Induction

18. Polarize

19. Ground

20. Remove Ground

21. Positive !