The electrostatic ping-pong illustrates the repulsive and attractive forces of electrostatics.
The conductive ball bounces back and forth between the two disk electrodes as long as an electric field of sufficient height is applied.
For this purpose, one disk electrode is connected to earth and the other disk electrode to the high-voltage source, e.g. our hand-held charging generator.
In the first step, the sphere is attracted to the charged electrode and, as the sphere is conductive, it takes on the charge of the electrode immediately on contact. As the ball and electrode are now equally charged, they repel each other and the ball swings towards the earthed electrode. The ball can discharge at the earthed electrode and is attracted to the charged electrode again.
