Volta's Hailstorm

When near an active Van de Graaff Generator, the tiny conductive balls inside begin to bounce up and down. It looks as if the pieces are "hailing" as they skitter and rebound. The explanation lies in the fact that the floor and ceiling of the cage become electrically charged. The Van de Graaff builds up a charge by induction as electrons are transferred from the ceiling to the floor. Since the balls lying on the floor are now negatively charged, they are attracted by the positively charged ceiling. But when the balls hit the ceiling, their negative charge is neutralized and they become positively charged instead. Down they fall to the negatively charged floor where they become positively charged upon impact. Back and forth, upwards and down - a veritable "hailstorm in a teapot." This flurry of activity will last as long as the Van de Graaff generator is running.
Volta's Hailstorm includes:
Transparent cage mounted on sturdy metal base (9" in diameter)
Ball terminal to attract electric charge
12" high, can be seen from a distance
Tiny polystyrene balls
Instructions with theory 10-615 - Volta's Hailstorm..............$36.75