1. Bell Work: Welcome Back
** Choose a new seat next to someone new in a new part of the room.
What was the best part of your break that included a change in momentum?
In what direction did you travel during the break? Where did you go?
When were you travelling with the greatest speed?
What was the best use of electricity during your break?

2. Electrostatics Chapter 18

3. Electrostatics
the study of static electricity – charge that is held in one place

4. Electric charges:
Positive: more protons (p+) than electrons
Negative: excess electrons (e-)
Neutral: equal # of p+ and e-

5. matter usually neutral or uncharged
through friction, electrons can be transferred and a static charge created
total # of e- and p+ stays the same

6. Ex: rub balloon on hair  electrons move from hair (+) to balloon (-), socks on carpet

7. like charges repel, different charges attract
any neutral object will be attracted to a charge

8. charge can be discharged (neutralized) by touching something that is grounded – connected to the earth

9. Conductors Insulators
Cannot hold a static charge
Hold a static charge well
e- can flow through
e- cannot flow through
usually metals or semimetals
usually nonmetals
silver, copper, gold, aluminum, silicon
plastic, glass, wool, air