Benjamin Franklin's travels and correspondence brought him into contact with some of the best scientific minds in Europe, and his own imagination was caught by the studies of electricity that had become fairly common in the 1740's. Although Franklin had never had any scientific training, his experiments on electrical phenomena were conducted with such skill and insight that he was soon recognized and respected as a scientist.

Franklin proposed that electricity was an "element diffused among and attracted by other matter." He identified two kinds of electricity -- one that was possessed by a body "undercharged with electrical fire" and another by a body "overcharged." Replacing the words "electrical fire" with the word "electrons" gives us the modern description of positive and negative charge. He went on to propose that when an "overcharged" body approached an "undercharged" one an electrical spark leaped between them, equalizing the amount of "electrical fire" in the two bodies. This would prove to be the first accurate description of the mechanism by which electrons pass between bodies of differing electrical potential.

some of the apparatus Franklin used for his experiments with static electricity

Franklin's best-known discovery was that lightning is caused by discharges of static electricity in the atmosphere. He made this discovery by fixing a metal key to a kite by a conducting thread of silk and flying it in a lightning storm. In effect, Franklin was diverting some of the electrical energy of the lightning through the key and into the earth. In the months following publication of his findings, several scientists in Europe were electrocuted trying to repeat the experiment. (Despite all the popular depictions of Franklin's experiment, there is absolutely no evidence that he was actually foolish enough to either hold onto the string or to touch the key during his experiment; the discharge of electricity would have been just as visible if the key was tied to the string as close to the ground as possible. Unfortunately, not every scientist who attempted to replicate Franklin's experiment was as practical as Franklin.) The immediate practical result of Franklin's experiment was the first lightning conductor. He suggested that pointed metal rods be placed on the roofs of houses and connected to the earth to divert lightning away from the structure of the houses, dissipating the energy harmlessly in the ground.

painting of Benjamin Franklin conducting his lightning experiment

SOURCE
Feldman, Anthony and Peter Ford. Scientists and Inventors, The People Who Made Technology from Earliest Times to Present Day. New York:Facts on File, 1979

SEE ALSO
Benjamin Franklin

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This page was last updated on 10/24/2017.