PURPOSE: To demonstrate that for conductors at the same electric potential the rate of discharge of the electric field is HIGHER for a conductor with a SMALLER radius. A charged conductor of a smaller radius produces a higher electric field.
DESCRIPTION: A Van de Graaf generator is made to discharge repeatedly to a large radius spherical conductor. When a smaller radius spherical conductor at the same potential is brought close to the charged dome of the Van de Graaf it will "steal" the electric field from the larger sphere at a more rapid rate even though they are at the same potential. A smaller radius conductor at the same potential will build a larger electric field more quickly.
A needle is connected to the Van de Graaf and causes a continuous discharge so that no electric field can build up. This is known as the "Lightning rod effect".
EQUIPMENT: Van de Graaff generator with ground sphere, small radius conducting sphere, ground wires.
SETUP TIME: 5 min.
Updated by JZ in 2/8/20005