Alessandro Volta invented the electrochemical battery. At the Gymnasium at Como, Italy, Volta invented the electrophorus (1775), a machine used to generate static electricity which he used, along with an electrometer made from straws, to conduct a series of electrostatic experiments. In 1800, he developed the voltaic pile, the first continuous source of electricity, after hearing of the discovery of 'animal electricity' by Luigi Galvani, who had demonstrated earlier that the muscles of a dead frog contracted when two different metals touched them. Volta repeated this experiment on other animals and on his own tongue. The pile consisted of an alternating column of zinc and silver discs separated by porous cardboard soaked in brine. This instrument revolutionized studies of electricity because it enabled continuous sources of electric current to be made available. This led quickly to advances in electrolysis (notably the electrolytic breaking down of water into hydrogen and oxygen), to the discovery of new elements and to the development of electromagnetism. In recognition of Volta's work, the SI unit of potential difference is named after him.
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