Alessandro Volta Biography (1745-1827)


Alessandro Volta knew what he wanted his life's work to be at a fairly earlyage. Volta was born in Como, Lombardy, Italy, on February 18, 1745. His family believed he was developmentally-impaired because he did not begin to talk until the age of four. When he turned seven, he caught up with, and began to surpass, his classmates. At age fourteen, Volta decided to become a physicistafter reading The History and Present State of Electricity by Joseph Priestley (1733-1804).

In 1774 Volta was appointed professor of Physics in the Como high school. Inthe following year he made his first major invention, a device called the electrophorous that used to generate static electricity. The electrophorous consisted of two metal plates. One plate was covered in ebonite which, when rubbed with a dry cloth, built up a negative static electric charge. The second plate, which had an insulated handle, was brought near the negatively charged ebonite plate. Since opposite charges attract, the ebonite attracted a positive charge in the second plate, which collected on the side nearest the ebonite. The side of the plate opposite the ebonite was left with a negative charge.By attaching a wire to the negative side of the second plate, the charge wasdrained away into the earth. By repeating the process, Volta was able to build, and store, a considerable positive charge on his plate. The electrophorous replaced the Leyden jar which, up until that time, was the standard deviceused for storing charges. Volta's invention became the forerunner of the modern capacitor which stores electricity in electric circuits.

Volta was duly proud of his invention, which he first described to Priestley.Volta became famous and in 1779 was appointed a professor at the Universityof Pavia. He continued to work with electricity, modifying the electrophorousso it could be used to measure weak electrical charges. He also became involved in a controversy which, eventually, led him to the invention of a devicefor which he became even more famous.

In 1791 Italian anatomist Luigi Galvani (1737-1798) made public a conclusionhe had drawn through his experimentation with electricity and muscles. He announced that an animal electricity existed. When two different metal probes touched the muscle in a frog leg, the animal electricity was released, Galvanisaid, causing the muscle to twitch. Galvani's theory received a large following, but not everyone accepted it. Volta strongly disagreed as did the illustrious scientist Charles Augustin de Coulomb (1736-1806). Volta began his own investigation into animal electricity in 1794 and found muscle tissue was completely irrelevant to creating the current. Only the presence of two differentmetals produced electricity; the fluid in the muscle merely enhanced the charge. The controversy raged on until 1800, when Volta built a device that produced a large flow of electricity. He filled bowls with a saline solution and"connected" them with strips of different metals. One end of the strip was copper; the other end was tin or zinc. By bending his strips from one bowl intoanother, Volta was able to create a constant flow of electrical current--theworld's first electric battery. Volta had proven that the metal was the source of the electricity, and animal electricity did not exist.

In the interest of making his battery smaller, Volta used round discs of copper, zinc, and cardboard that had been soaked in a saline solution. He stackedhis discs one on top of the other; attaching a wire to the top and bottom ofhis pile allowed the electric-current to flow. The invention of this "Voltaic pile" marked the apex of Volta's career. Volta died in Como on March 5, 1827. His greatest honor was bestowed when the force that moves electric currentwas named the Volt.

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