Bouncing Ping Pong Balls (5B10.30)

Description:

A variation of Franklin's Bells. Aluminum coated ping pong balls bounce up and down between two charged metal plates due to electrostatic forces on the balls.

Procedure or Operation Notes:

Levitating Pith Ball:

Start turning the handle on the Wimshurst Machine and the pith ball (which has the same charge as the bottom plate) will be attracted to the top plate.

Bouncing Ping Pong Balls:

Hold the insulating (phenolic) tube so that it is angled in between the two plates and hold an aluminum coated ping pong ball in your palm. While turning the handle of the Wimshurst Machine, drop the ball through the tube so that it bounces off the bottom plate. When the ball makes contact with the bottom plate, it picks up that charge. The ball will then be attracted to the top plate where it will pick the top plate's charge. The ping pong ball will continue to bounce between the two plates as long as you keep turning the generator handle.

References, Comments, or Footnotes:

1) While this is named after Benjamin Franklin who used it with his lightning rod experiments, it was originally discovered ten years earlier (1742) by Scottish inventor Andrew Gordon and his "electric chimes."

2) Franklin's Bells [Wikipedia].