History

Fascinating History: Ben Franklin’s Famous Electricity Experiment (10 June 1752)

Photograph of painting depicting Franklin’s famous kite and key experiment. Circa 1911.
Artist: Charles E. Mills (American, 1856-1956)
U.S. Library of Congress, Digital Id#cph 3b42841

On 10 June 1752 Benjamin Franklin conducted his famous–and legendary–experiment on electricity during a thunderstorm. He was not trying to discover electricity but determine the connection between lightning and static electricity

Franklin constructed a kite with a wire at the top to act as a lightning rod. The kite’s bottom used hemp string that once wetted with rain would become a conductor for an electrical charge. And with a silk string attached, he stood in the doorway of the shed as the thunderstorm approached. His son William helped him get the kite airborne. For a while nothing seemed to happen and he was ready to give up when he noticed several loose strands of hemp were erect. As he moved his finger near the key he had attached, he felt electricity. Using a Leyden jar, the static electricity was collected to be discharged later.

He reported his experiment in the Pennsylvania Gazette (19 October 1752) documenting what he had learned of the connection between lightning and static electricity. Up to this point in time, it was thought electricity consisted of two opposite forces. Franklin determined it was instead a common element and fluid leading to the single fluid theory. Simply put, when you charge something (like a car battery or something similar), you have a positive charge (+) that flows to the negative (-).  Franklin created new language that we still use today to describe how this force is used:

  • Battery
  • Charge
  • Condenser
  • Conductor
  • Plus
  • Minus

A similar experiment had been conducted in France by Thomas-François Dalibard a year earlier. A year later Georg Wilhelm Richmann attempted the same thing in St. Petersburg. The outcome though was tragic: he was struck by ball lightning and died. Ball lightning is rare and scientists to this day are baffled by its properties. Franklin developed the lightning rod because of this experiment. This device allows lightning to pass harmlessly through the rod and cables into the ground avoiding any conductive material. Houses and buildings could be protected from lightning strikes. From there it would be used on ships and much later installed on airplanes to protect them as well. Franklin received the Copley Award from the Royal Society for his experiments.

Over the years his experiment got mixed up and rewritten becoming a myth. Instead of standing in the shed, he was outside and the kite was struck by lightning. Except that never happened yet it was taught in schools as fact for quite a long time. Mythbusters took on the myth and showed if Franklin had done it as the myth said he did, he would have been killed. They did prove that his real experiment was valid as they flew a kite on a sunny day and got static electricity.

Sources

Videos

Discovery. “Did Lightning Strike Benjamin Franklin’s Kite? | MythBusters | Discovery.” Video. YouTube, March 8, 2024. Accessed June 9, 2026. https://www.youtube.com/watch?v=ISRl3WEuU-s.