# Homework Help: Van de Graff Generator: Electrostatics, why do objects repel the generator

1. Apr 21, 2009

### jamba88

1. The problem statement, all variables and given/known data

a) Why do pie pans fly off the Van de Graff Generator when turned on?

b) When foam peanut are placed inside a pie pan with the Generator turned on, what causes the foam peanuts to fly out?

c) Why does a person's hair stand up when they touch the generator?

2. Relevant equations
No relevant equations

3. The attempt at a solution
I'm not sure if my answers are correct or if I'm elaborating enough. Like should I talk about conductors/insulators...charging by conduction/induction.

a) Since the van de graff generator's dome is positively charged and the the pie pans tend to be positively charged, then the pans fly off because like charges repel.

b) The foam peanuts are insulators. The van de graff generator transfers charge to the pan, leaving it positively charged. This is charging by conduction. The pan transfers the charge to the foam peanuts. The foam peanuts fly off the pan because they are both positively charged and so the peanuts repel the pan.

c) Hair stands up when a person touches the van de graff generator because the body is a conductor. Postive charge moves freely through the body into the hair making it stand up.