On June 10, 1752, Benjamin Franklin took out a kite during a storm to see if a key attached to the string would fire an electric charge. Or so the story goes. In fact, historians aren’t entirely sure of the date of Franklin’s famous experiment, and some have wondered if it took place.
Even though Franklin’s kite and key experiment did happen, it didn’t turn out the way many people think. Contrary to popular myths, Franklin did not conduct the experiment to prove the existence of electricity. Also, it’s highly unlikely that lightning struck a key while Franklin was flying a kite, because if it did, Franklin would likely be dead.
Franklin did not write much about the experience
Benjamin Franklin and his son William using a kite and key for an experiment, June 1752.
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Everything we know about the kite and Franklin’s Key Experiment comes from two sources. The first is a letter that Franklin wrote to his friend Peter Collinson in October 1752 and which was published in the The Pennsylvania Gazette and read before the Royal Society. The second is a section from Joseph Priestley’s 1767 book History and current state of electricityin which Priestley recounted what Franklin had presumably told him about the experience.
In the letter, Franklin wrote that a “successful experiment in Philadelphia” using a kite and a key, and detailed how the experiment could be replicated. He did not say when the experiment took place or whether he actually conducted it. Fifteen years later, Priestley provided some additional details, writing that 46-year-old Franklin and his 22-year-old son William conducted the experiment in June 1752.
Franklin scholars have speculated that the experience occurred around June 10, although no one is quite sure what date it happened. Some have speculated that it happened later in 1752, while others questioned whether it happened at all, or at least acknowledged that there was room for doubt.
“The kite episode, so firm and steeped in legend, actually turns out to be dark and mystifying,” wrote Carl Van Doren in his 1939 Pulitzer Prize-winning biography, benjamin franklin. The legendary appearance of the kite and key experiment led people to believe, wrongly, that it marked the discovery of electricity.
Ben Franklin did not discover electricity
Electricity was already a known phenomenon in the middle of the 18th century. There were, however, debates about the nature of this phenomenon, and Franklin was among a group of philosophers and scientists who theorized that lightning was a form of electricity.
In March 1750, Franklin wrote a letter to his friend Collinson about his idea for a lightning rod. In July, he published an idea for an experiment using a lightning rod to try to capture an electric charge in a “leyden jar”, a container for storing electric charges, thus demonstrating that lightning was a form of electricity.
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Franklin’s ideas circulated in Europe, and in May 1752 two French scientists – Thomas Dalibard and M. Delor – separately performed successful versions of Franklin’s experiment. According to Priestley, Franklin had not yet heard of these successes in June 1752, when he was awaiting the construction of a spire to conduct his own lightning rod experiment.
Apparently, Franklin decided that instead of waiting for the arrow, he could test his theory by flying a kite with a key attached to its string when he felt a thunderstorm approaching. “[D]reading the ridicule that too often accompanies failed scientific attempts, he only communicated his experimental intent to his son, who helped him raise the kite,” Priestley wrote.
Ben Franklin was not struck by lightning
Benjamin Franklin’s lightning rods as described in Franklin’s book Experiments and Observations on Electricity.
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So what would that experience have really been like? Although many artists have tried to portray him, “most of the images and drawings you see depicting Franklin in this experiment are inaccurate,” says Harold D. Wallace Jr., curator at the Labor and Industry Division at the Smithsonian National Museum. of American history.
“They show Franklin standing in the middle of a field,” he says, “while he and William were most likely inside some sort of shed or lean-to or something to keep them from raining, at the in case the rain starts.” (Franklin probably started the experiment after he felt lightning in the air, but before the rain started falling, Wallace said.)
Franklin’s goal probably wasn’t for the kite and key to be struck by lightning; and indeed Priestley never claimed that they were hit by lightning. Had they been, Franklin would almost certainly be dead or at least seriously injured (in 1753, German scientist Georg Wilhelm Reichmann died trying to conduct Franklin’s lightning rod experiment).
What probably happened was that the key picked up an ambient electrical charge from the storm. Priestley wrote that Franklin touched the key and felt the charge, confirming that he had picked up electricity from the lightning.
Even though Franklin never did the kite and key experiment, he came up with the lightning rod idea that others tested. Together, these experiments helped prove that lightning was a form of electricity that people could harness, both to protect tall buildings from damage and to perform more experiments.
“The idea of mitigating natural hazards is such a game-changer,” says Michael Madeja, director of education programs at the American Philosophical Society Library and Museum. “The lightning rod also helped provide a decent charging source for things like leyden jars or other electrical experiments.”
