Ben Franklin Electricity
By R.W. Hurst, Editor
Ben Franklin’s electricity experiment in 1752 used a kite and key to prove that lightning is electrical in nature. His discovery helped lay the foundation for the study of electricity and influenced the development of lightning rods and electrical theory.
Quick Reference: Ben Franklin Electricity
Ben Franklin was a great American inventor and innovator. His electrical experiments formed the basis for other inventions that we still use today. Explore deeper insights into the debate around who invented electricity and who discovered electricity, where Franklin’s name often takes center stage.
Benjamin Franklin began studying electricity after attending a lecture about it in Scotland in 1743. Five years later, he sent a letter on it to the Royal Society. In 1751, he published his book of experiments on electrical currents in England. To understand where Ben Franklin fits into the broader context, refer to a timeline of the history of electricity, which outlines key discoveries and milestones leading up to and following his famous experiment.
While visiting Boston in 1746, Franklin witnessed some electrical experiments performed by Mr. Spence. Shortly after his return to Philadelphia, the Library Company received a glass tube from Mr. Collinson, a member of the Royal Society from London, along with instructions for conducting experiments with it. With this tube, Ben Franklin initiated a series of electrical experiments that led to discoveries that seem to have had a more profound material impact on the world's industries than any other human intellect discovery. Our page on how Ben Franklin discovered electricity provides more detail on his innovative kite-and-key test and its lasting influence on electrical science.
His electricity experiments included an infamous event in the summer of 1752 when he made a kite with silk, which he sent up with a cord made of hemp. To avoid damaging the paper in the rain, he used silk instead of paper. At the top end was an iron point, and at the bottom part of the string was a key. Accompanied by his son, Ben Franklin raised the kite while staying under a shed to avoid getting wet. The long wait almost made him give up until he noticed loose fibres on the string. When his knuckle touched the key, he received a strong spark with an electrifying sensation. The key drew repeated sparks that charged the vial, and all the experiments made yielded electricity. Learn more about the evolution of power in our article on the history of electricity, which includes Franklin's work alongside other scientific pioneers.
He was very smart. He was not afraid to experiment. When a thought popped in his head, like lightning is a source of electricity, he had the determination to prove it. The story is that he and three of his friends were trying to analyze static electricity and experiment with it. Two of his friends got electrocuted while they were working on this, so Franklin decided to do the kite experiment alone. Franklin’s early theories set the stage for future inventors like Thomas Edison and electricity, who later transformed those ideas into practical technologies.
Ben Franklin's experiments on electricity laid the foundation for many inventions, including electricity, batteries, the incandescent light bulb, electromagnetic fields, generators, transformers, and other related items. His experiments became the origin of the "plus" and "minus" nomenclature that are still in use today. The positive and the negative charges helped identify the atmospheric and frictional electricity.
Ben Franklin is rightly considered the principal founder of the scientific study of electrical phenomena. These Letters are the reports of his experiments, the theories he formed to explain the results of these experiments, and more speculative theories he extrapolated from his observations and analysis of his findings.
The single most important discovery noted in these letters is that of polarity, which means that he found all electrical potentials were not equivalent, but could be observed holding either of two opposite charges. To these he assigned the names we still use, positive and negative. Unfortunately, from our point of view, he assigned them in the opposite sense to our understanding -- "positive" meaning a deficit of free electrons -- which is why we now call the electron a negatively charged particle. The broader history of electricity reveals how Franklin’s contributions intersected with global discoveries across centuries.
