Van de Graaff Confetti

Materials: ★★☆ Available in most school laboratories or specialist stores
Difficulty: ★★☆ Can be done by science teachers
Safety: ★★★ Only to be attempted with adequate safety procedures and trained staff

Categories: Van de Graaff Generator

Alternative titles: Dancing Confetti, Electrostatic Confetti Fountain

Summary

When confetti is placed on the dome of a Van de Graaff generator, the pieces quickly become charged and repel each other. This causes the confetti to jump, scatter, and sometimes hover above the dome, vividly demonstrating that like charges repel.

Procedure

Place the Van de Graaff generator in an open area where loose confetti can safely scatter.
Put a handful of lightweight confetti or tissue-paper bits in a plastic bowl on top of the dome.
Switch on the generator to begin charging the dome.
Watch as the confetti pieces gain the same charge and begin to repel each other, flying off the dome in different directions.
Turn off the generator and discharge the dome with a grounding rod after the demonstration.

Links

Van de Graaff Confetti Explosion - Jefferson Lab:

Variations

Try different materials—tissue paper, aluminum foil bits, feathers, or Styrofoam beads to compare effects.

Safety Precautions

Always use the grounding rod to safely discharge the dome before and after use.
Avoid performing near sensitive electronics, as sparks and static discharges may cause interference.
Ensure participants do not touch the dome while it is charged.

Questions to Consider

* Why do the confetti pieces fly apart instead of staying on the dome?

How does this demonstration show the principle that like charges repel?
What properties of the confetti (e.g., mass, material, surface area) affect how they move?
How does this demonstration compare to the pie plates or hair-raising Van de Graaff demonstrations?
Could this model be used to explain natural phenomena, such as how particles behave in lightning storms?