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Most Americans are familiar with the following story. benjamin franklin and his famous 18th century experiment he put a metal key on it on a kite See if lightning can pass through metal during a thunderstorm. That’s largely because the many iconic illustrations commemorating this event have entered people’s imaginations and become part of our shared cultural lore. However, according to some sources, most of these classic illustrations are full of historical errors. new paper It was published in the journal Science and Education.
Franklin’s quest for electricity began when he approached the age of 40 after a successful career as a printing entrepreneur. His scientific interest was piqued when he saw a demonstration by a scientist and impresario in 1743. archibald spencer, known for performing a variety of funny parlor tricks with electricity. He soon began a correspondence with an English botanist. Peter Collinson And began recreating some of Spencer’s most memorable parlor tricks at home.
He had guests rub the tubes to create static electricity and kiss them to get electrocuted. He designed a fake spider suspended by two current-carrying wires that appeared to swing back and forth automatically. And he devised a game called “Treason” in which a portrait of King George was wire-tapped so that anyone who touched the king’s crown would be shocked. And he once infamously electrocuted himself while trying to kill a turkey with electricity.
Among his many insights into this phenomenon, Franklin notes how sparks jump between objects, and that lightning is simply a giant electrical spark, similar to that produced from an electrically charged Leiden jar. I concluded that there is. To test his theory of the nature of lightning, Franklin published a paper proposing experiments with high iron bars to “pull electric fire” out of clouds. The experimenter stands on insulated ground protected by a similar enclosure. A soldier’s sentry box. Franklin reasoned that a charged cloud passing over a pointed rod would draw electricity from the cloud, so sparks should occur when the man brought his knuckles close to the metal rod.
According to new paper author Breno Arcioli Moura, a science historian and educator at ABC Federal University in Brazil, there is no record of Franklin conducting the Sentry Box experiment. However, the French name Thomas Francois Dalibard bottom. Dalibard read Franklin’s published papers and conducted his version of the sentry box experiment in Paris on May 10, 1752, using a vertical bar 50 feet long. Others across Europe soon followed suit. It was a rather dangerous experiment, as evidenced by an unfortunate accident. Georg Wilhelm Reichmann. He tried to replicate his experiment, but a ball of glowing electrical charge traveled down a thread and flew into his forehead, killing him instantly. This was probably the first documented example of a ball lightning.
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Franklin apparently was unaware of these attempts when he devised a simpler kite experiment along similar conceptual lines. The established explanation is something like this: In June 1752, in anticipation of a thunderstorm outside Philadelphia, Franklin made a kite by nailing two cedars together in a cross or “X” shape to make a large silk handkerchief. Silk is a body-friendly material as it can withstand rain and thunderstorm winds. He attached a wire to the top of the kite to act as an impromptu lightning rod. A hemp string was attached to the bottom of the kite to provide conductivity and was attached to the Leyden jar by a thin metal wire. The silk string that Franklin had was also attached to the hemp. A metal key was used to connect the hemp and silk strings.
Franklin then stood under the roof of the shed to make sure he grabbed a dry piece of silk thread to prevent conductivity. Franklin’s son, who was 21 at the time, helped him fly the kite, and the family calmly waited. Final, Franklin observed loose filaments of twine to be “upright”, indicating that they were electrically charged. As he pressed his knuckles against the keys, an electrical spark was generated. This proved that lightning is static electricity. Contrary to popular belief, Franklin was not struck by lightning. If so, he probably wouldn’t have survived. The spark was caused by subjecting the kite/key system to a strong electric field.
Moura said there are two main historical sources for the aforementioned details of the kite experiments. One is Franklin’s short letter to Collinson in October of the same year, which was reprinted in the Philadelphia Gazette (with some minor wording variations). Another account was written 15 years later by a friend and colleague of Franklin’s. Joseph Priestleyin the latter 1767 paper, Electricity history and current status
