Electrostatics was first noticed sometime in 600 B.C. when the Greek philosopher Thales discovered that amber attracted light objects when rubbed. The phenomenon not only demonstrated a fundumental concept of electrostatics, but also gave us the word "elektron" meaning amber in Greek.

It is an elementary physical fact that extremely high voltages can be generated by the repeated contact and separation of dissimilar substances, a process that is otherwise known as friction.

The first known electrical generator was built in 1660 by the German experimenter, Otto von Guericke (also known as the inventor of the air pump). Guerickes generator consisted was made by pouring molten sulfur into a spherical glass container about the size of a child's head. When the sulfur cooled the glass was broken to remove the sulfur ball. The sulfur ball was then equipped with an iron axle and mounted on a wooden frame that allowed it to spin freely. When a persons dry hand was applied to the rotating sulfur sphere, the ball would become electrified, attract small objects, make a crackling sound and glow faintly in the dark.

You may have noticed when a balloon rubs against your head that your hair rises towards it, or when you rub flannel with a glass rod that you can see the flannel hang unnaturally toward the rod. This is because you've created a voltage between the flannel and the rod.

With a Van de Graff generator the effect of rubbing flannel against a glass rod is expedited. An electric motor spins the lower pulley, and a rubber belt runs from the lower pulley to the upper pulley. The brush at the bottom of the pulley supplies electrons to the upper dome via the the belt and the discharging comb (see figure above). The discharging comb takes electrons from the belt and places them on the dome creating an excess of electrons on the upper dome. This excess of electrons creates a charge or a voltage on the domb that gives a spectacular light display.

The fantastic sparks are created when the abundance of electrons on the dome gets large enough that it ionizes the surrounding air and the air turns from an insulator to a conductor. With the air like this the electrons leap off the domb creating a brilliant spark.