Repulsion from a Van de Graaff - Physics Demonstrations - Repulsion from a Van de Graaff | Physics Undergraduate Labs

Van de Graaff generators produce voltages exceeding 200 kV. While current is low, the discharge can be startling and may affect individuals with pacemakers or other electronic medical devices. Announce the demonstration before activation and ask anyone with concerns to step back. Never touch the sphere or charged objects while the generator is running.

Purpose

Lightweight objects on a Van de Graaff generator acquire charge and fly off dramatically, illustrating that like charges repel and that electrostatic forces can easily overcome gravity.

Aluminum pie plate tilting off the chrome dome of a Van de Graaff generator, caught mid-flight as electrostatic repulsion launches it upward

Small clear plastic container filled with foam packing peanuts sitting on top of the Van de Graaff generator dome

Figure 1: An aluminum pie plate lifts off the Van de Graaff dome as it acquires charge and is repelled. Plates eject one at a time from a stack placed on top of the sphere.

Figure 2: Foam packing peanuts in a plastic container fastened to the banana plug on top of the Van de Graaff. When the generator runs, peanuts acquire charge and eject in bursts, like popcorn.

Styrofoam Peanuts

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Safety Warnings

Warning: High Voltage Electrical Hazard

Purpose