Qualitative Existence Of Electrostatic Forces
To demonstrate the existence of electrostatic forces.
Van de Graaff, ground sphere, and suspended aluminum foil cylinders.
The Van de Graaff is first turned on, charging the dome, and the ground sphere by induction; sparks between them indicate the existence of high voltages. The Van de Graaff is then turned off, and conducting aluminum foil cylinders hanging from strings are inserted between the dome and the ground sphere. The cylinders move back and forth between the dome and the ground sphere, demonstrating the existence of electrostatic forces.◙