| The set of parallel plates used to show the electrical
hail or the dancing images demonstration are typically about six to eight
inches in diameter if they are in the open, and somewhat smaller if they
are inside a bell jar.
The upper plate is connected to the prime conductor of an electrostatic machine, and the lower plate grounded. The demonstration starts with pith balls or paper figures lying on the lower plate. They become charged by induction, and are attracted to the upper plate. Once there, they pick up a charge and are repelled downward. The process then repeats itself.
The apparatus at the far right is in the Garland Collection of Classical Physics apparatus at Vanderbilt University.
The electric hail at the left below is at Transylvania University in Lexington, Kentucky, and the identical apparatus at the right is in the Garland Collection of Classical Physics Apparatus at Vanderbilt University.
| This example of Volta's Hail apparatus is at Oberlin College
None of the last three pieces of apparatus is marked, but
the typical price was in the $3.00 to $4.00 range.