experiment uses the Wimshurst static electric generator to produce high
voltages that are then stored on the Leydon Jar. The jar consists of two
aluminum cups separated by a plastic dielectric cup. Once the Leydon Jar
is charged it may be taken apart and all of the parts can be touched together,
but once it's reassembled if a discharging rod is connected between the
inner and outer aluminum cups a spark will occur. This experiment shows
that charge is stored on the surface of the dielectric and until a connection
is made between the inner and outer surfaces it will not discharge.