1. Do Now: Make a list of 5 characteristics of charge.
Write down 2 ways electricity is like gravity. Write down 2 ways the two are different.
Draw a force diagram for a levitating balloon that is negatively charged and is interacting with a negatively-charged rod.

2. Charge is conserved.
Electrons are transferred.
Like charges repel; opposite charges attract.
Electrical forces can act
at a distance.
Charge is quantized.
Conductors are materials that electrons move through easily.
Insulators are materials whose electrons are bound more tightly so they are not free to move.
Charging by friction, conduction, induction, polarization.

3. Would you say there is an electrical force?
Remember how objects behaved (paper, etc).
Was there acceleration? Was there force?
What has to be true for there to be an electrical force?
What does the strength of the force depend upon?

4. Coulomb’s Law
k = 9 x 109 N∙ m2/C2

5. Two balloons are charged with an identical quantity and type of charge: nC. They are held apart at a separation distance of 61.7 cm. Determine the magnitude of the electrical force of repulsion between them.
Felect = (9.0 x 109 N•m2/C2) • (6.25 x 10-9 C) • (6.25 x 10-9 C) / (0.617 m)2
Felect = 9.23 x 10-7 N

6. Force Diagrams and Electrical Force

7. Van De Graaf Generator time!