7D30.70 - Cyclotron Demonstration Model

First attach the positive lead to the Van de Graff and the negative lead to ground. The conductive tape that is on the cyclotron alternates voltage from positive to ground. As the particle is given a bump, it rolls over the first piece of conductive tape and is given that charge. Since like charges repel, it pushes the particle away from that strip. Also, since opposite charges attract, as the particle is pushed away from the first line of tape, it sees an opposite charge on the second piece of tape and is attracted to it. As the particle rolls over the second piece of tape, the charge on the ball is reversed and the process repeats.

The ping pong ball will reach its terminal velocity rather quickly, but when fully accelerated, the particle should be circling near the edge of the cyclotron rim.