Did Benjamin Franklin really discover electricity with a kite and a key?

On a dark and stormy summer night in 1752, Benjamin Franklin flew a kite with a key attached to the string, waiting in anticipation for lightning to strike. Dramatic lightning would herald the discovery of electricity (or, as Franklin called it “electric fire”), … or so it is rumored.

But is there any truth in this story? Did Franklin really discover electricity when he was zapped by lightning during this experiment?

Although most people know Benjamin Franklin – an American Founding Father, legendary statesman, and the face of the US $ 100 bill – for his political contributions, Franklin was well known in his day as a scientist and inventor: a true polymath. He was a member of several scientific societies and was a Founding Member of the American Philosophical Society. As a result, he kept abreast of the most pressing scientific questions that occupied the scientists of his time, one of which was the nature of lightning.

As for the kite and wrench experience, most people are familiar with the version in which the metal wrench acted as a lightning rod, and Franklin later “discovered” electricity when lightning struck his kite. However, several details about this experience are unknown, including when and where it occurred. Some historians even doubt that it took place.

Related: Did Benjamin Franklin really want the turkey to be America’s national bird?

For starters, it’s a common myth that Franklin discovered electricity. Electricity had already been discovered and used for centuries before Franklin’s experiment. Franklin lived from 1709 to 1790, and during his time electricity was understood as the interaction between two different fluids, what Franklin later called “more” and “less”. According to French chemist Charles François de Cisternay du Fay, materials with the same type of fluid would repel each other, while opposing fluids would attract each other. We now understand that these “fluids” are electrical charges generated by atoms. Atoms are made up of negatively charged electrons orbiting a positively charged nucleus (made up of protons and neutrons).

Before Franklin’s experiment, it was not known whether lightning was electrical in nature, although some scientists, including Franklin, had just speculated that. Page Talbott, author and editor of “Benjamin Franklin: In search of a better world(Yale University Press, 2005) and the former president and CEO of the Historical Society of Pennsylvania in Philadelphia, said Franklin was particularly interested in this issue because the lightning strikes had caused catastrophic fires in towns and villages where the houses were made of wood, which many houses in the United States were at the time.

“By attaching a key to the string of a kite, thus creating a conductor for the Electrical charge, he demonstrated that a sharp metallic object placed at a high point on a building – connected to a conductor that would carry electricity away from the building and into the ground – could make a huge difference to the long-term safety of residents, ” Talbott told Live Science in an email. In other words, by creating a lightning rod, Franklin was helping protect houses and wooden buildings from being directly struck by lightning.

Lightning rods are metal rods placed at the top of structures, connected to the ground by a wire. If lightning strikes the building, it will likely strike the electrically conductive rod instead of the building itself and cross the wire safely to the ground.

Here’s how the experiment worked; standing in a shed, Franklin flew a kite, made of a simple silk handkerchief stretched over a cross made of two cedar blades, during a thunderstorm. The tail of the kite was made of two materials – the upper end attached to the kite was made of hemp twine and attached to a small metal key, while the lower end, held by Franklin, was made of silk . The hemp would be soaked in the rain and conduct an electrical charge, while the silk twine would stay dry as it is kept in the shelter.

As Franklin observed his kite flying, he saw that the hemp strands were standing upright as they began to build up electrical charges from the surrounding air. When he placed his finger near the metal key, he reportedly felt a sharp spark as the negative charges that had built up on the key were attracted to the positive charges in his hand.

An illustration of Benjamin Franklin conducting his kite and wrench experiment during a thunderstorm. (Image credit: Keith Lance via Getty Images)

A few publications at the time reported on the experience. “[Franklin] issued a statement on the experience in the Pennsylvania Gazette, the journal he published, October 19, 1752, ”said Talbott. He then sent the text of this statement to a patron of the American Philosophical Society named Louis Collinson; Franklin had spent the last years communicating to him his theories and offering him his experiences concerning lightning.

Franklin referred to the experience in his autobiography, and other colleagues in Europe have written about it as well, Talbott said. Notably, the experience appeared in the 1767 book “History and current state of electricity“by Joseph Priestley, an English chemist. Priestley heard about the kite and key experiment from Franklin himself about 15 years after the fact, and in his book he wrote that it was was produced in June 1752. However, exactly when the experiment took place in Franklin and when he did, is a matter of debate.

There are historians who doubt that Franklin actually experienced it himself, or simply sketched out its possibility. In his book “Bolt of Fate: Benjamin Franklin and his electric kite hoax“(PublicAffairs, 2003), author Tom Tucker stated that Franklin wanted to thwart William Watson, a fellow of the Royal Society of London and prominent electrical experimenter. Watson had sabotaged the publication of some of Franklin’s previous reports and ridiculed his experiments in the Royal Society, Tucker wrote. Could Franklin have felt compelled to make up the kite story to get revenge on Watson?

Tucker also noted that Franklin’s description of his experience in the Pennsylvania Gazette was phrased in the future conditional: “As soon as one of the thunder clouds passes over the kite, the sharp wire will fire it. electric … “Franklin could have simply said that the experiment could, in theory, be carried out. Since his statement has a few missing details – Franklin did not include a date, time or location, for example – it is possible that the American diplomat did not carry out the experiment himself.

However, some historians are still not convinced that the experiment was not carried out, pointing out the great respect for scientific activities. Franklin’s pundits, like the late American critic and biographer Carl Van Doren, also point out that Priestley specified the month in which Franklin performed his experiment, suggesting that Franklin must have given him specific details directly.

Originally posted on Live Science.


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