In electricity's earlier days, scientists used the buildup and release of static electricity (yes, the same thing that makes your clothes stick together in the dryer) to store and release energy.
Before electricity could be produced by conventional methods, electrostatic devices were the primary means of generating high voltages. Using induction — a redistribution of the electrical charge in an object — these machines change mechanical energy (the energy of motion) into electrostatic energy. Inventors in both the United States and Europe developed their own versions of the generator, and British scientist James Wimshurst built one of the more effective models in the early 1880s.
Known as an "influence machine" because no friction is used to create electricity, the Wimshurst generator has a distinctive appearance. The structure is composed of a pair of discs fixed on a vertical axis, a couple of brushes made out of metal, and a spark gap between a set of iron globes. When put in operation, each disc is spun in opposite directions, revolving past the fixed brushes, creating charges that are increased and collected by metallic fixtures close to each of the discs. The collective charges gain strength, creating sparks that shoot between the globes.
The Wimshurst electrostatic generator was the last great electrostatic machine ever made. The advent of more modern systems may have rendered it outmoded in terms of practical usefulness, but it holds an important place in science today. From elementary school science classes to university physics courses, the Wimshurst is often the electrostatic device of choice for demonstrations of static electricity.
