When small bits of aluminum foil, pith, or vermiculite are placed in the cylinder and the upper plate is brought near an operating generator, the particles will bounce rapidly. They are first attracted to the upper plate but, after touching, are violently repelled downward, where they lose their charge upon contacting the lower plate. They are then ready to be attracted back to the upper plate. The precipitation of smoke may also be shown. The unit's cylinder is Ø15cm. Include vermiculite and metal screening.