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Most Americans are familiar with the story of Benjamin Franklin and his famous 18th century experiment where he attached a metal key to a kite during a thunderstorm to see if lightning would pass through the metal. That’s because of the many iconic illustrations commemorating the event that caught the popular imagination and became part of our shared culture. But most classic illustrations are riddled with historical errors, according to a new paper published in the journal Science and Education.
Franklin’s exploration of electricity began when he was almost 40 years old after a successful career as a businessman in the printing business. His scientific interest was sparked in 1743 when he saw a demonstration by scientist/showman Archibald Spencer, who was known for performing various amusing parlor tricks involving electricity. He soon began a correspondence with a British botanist named Peter Collinson and began copying some of Spencer’s impressive parlor tricks in his own home.
He would wipe the guests with a pipe to create static and then kiss them, creating an electrical shock. He designed a fake spider suspended by two electrified wires so that it seemed to turn on itself. And he created a game called “Treason,” in which he placed a picture of King George so that anyone who touched the monarch’s crown would be shocked. And once he shocked himself while trying to kill a turkey with electricity.
Among his many insights into the phenomenon, Franklin discovered how sparks jump between objects and concluded that lightning was simply a large electrical spark, similar to that produced from charged Leyden jars. . To test his theory about the nature of lightning, Franklin published a paper proposing an experiment with a long iron rod wire to “draw electric fire” from a cloud, with experiment standing on insulated ground to protect an enclosure similar to. soldier watch box. Franklin reasoned that an electrified cloud passing through a pointed rod would draw electricity from the cloud, so that if the man moved his knuckle closer to the metal rod, there should be sparks.
There is no record of Franklin doing his sentry-box experiment, according to Breno Arsioli Moura, a history of science and teacher at the Federal University of ABC in Brazil, who wrote the new paper. But a Frenchman named Thomas-Francois D’Alibard did. D’Alibard read Franklin’s published paper and used a 50-foot-long vertical rod to conduct his version of the sentry-box experiment in Paris on May 10, 1752. Others throughout Europe soon followed suit. It was a dangerous experiment, as the unfortunate Georg Wilhelm Reichmann proved. He also tried to replicate the experiment, but a glowing ball ran through the thread, bounced off his forehead, and killed him instantly—perhaps the first documented instance of ball lightning.
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Franklin seems to have been unaware of these trials when he devised his simpler kite experiment along similar conceptual lines. The established account goes like this: Anticipating a thunderstorm in June 1752, outside of Philadelphia, Franklin made a kite from two strips of cedar nailed together in the shape of a cross or “X,” with a large silk handkerchief formed. the body, because silk can withstand the wet and wind of a thunderstorm. He attached a wire to the end of the kite to serve as a makeshift lightning rod. Hemp string is attached to the bottom of the kite to provide conductivity and attached to the Leyden jar by a thin metal wire. The hemp was also attached to a silk thread that Franklin was holding. The joining of hemp threads and silk is a key metal.
Next, Franklin stood under a roof eaves to make sure he was holding a dry part of the silk thread so it wouldn’t become conductive. Franklin’s son, who was 21 at the time, helped him raise the kite, and they sat down to wait. Eventually, Franklin observed the loose filaments in the twine “stand erect,” indicating electrification. He pressed his knuckle against the key and was rewarded with an electric spark. This proves that lightning is static electricity. Contrary to popular myth, Franklin was not struck by lightning; if he was, he probably wouldn’t have lived. The spark results from the kite/key system being in a strong electric field.
According to Moura, there are two main historical sources for the aforementioned details about the kite experiment. One is a short letter written in October of that year by Franklin to Collinson, reproduced in The Philadelphia Gazette (with some textual variations). Another account was written 15 years later by Franklin’s friend and colleague, Joseph Priestley, in the latter’s 1767 treatise, The History and Present State of Electricity
