Northwestern Physics Demos                                 Go back to Electrostatics 
DCS# 5B30.35NWU# Location:    9 A 2
title: Point and Ball discharge using Van de Graaff

Each grounded sphere is placed one eraser length from the Van de Graaff.  The small sphere gets the discharge.
A sharp point (key or paper clip) brought near will take the discharge in tiny sparks.

   How close does the larger grounded sphere have to be to take over the discharge sparks
   What happens if a sharp point, like a key, is brought into the vicinity of the Van de Graaff terminal?  (Be sure you are grounded when you do this, for comfort's sake.)
pix of set up