Electricity & Magnetism: Styrofoam Peanuts in a Metal Cup

PIRA Class: 5B20.40

Purpose:
To demonstrate that the electric field/ net charge within a hollow conductor is zero. 

Description: 

With peanuts in the metal cup on top of the Van de Graaff, turn on Van de Graaff; repeat w/ peanuts inside Styrofoam cup.

- Peanuts within metal cup stay charge free, "protected" by the metal cup.

- Peanuts within Styrofoam cup (or plastic beaker) acquire a net charge, and dramatically fly out due to the force of the electric field.

(See Demo: 5A50.30 Van de Graaff Generator for demo preparation and Van de Graaff operation)

NOTE: Do not reuse Styrofoam peanuts. The net charge that they acquire is very difficult to remove and they end up statically clinging to plastic containers that they are put back into. Rinse out synthetic cups with water to remove any excess charges before reusing synthetic cups.

Equipment:
Metal cup, Styrofoam cup & peanuts (unused), Van de Graaff generator

Location:
Shelf 312, 352