Benjamin Franklin is one of the most famous American scientists and statesmen. He is well known for his pioneering work and experiments with electricity. One of his most famous experiments was the kite and key experiment he conducted in 1752 to demonstrate that lightning is a form of electricity. This groundbreaking experiment revolutionized our understanding of electricity but also nearly cost Franklin his life.

Franklin's Interest in Electricity

Benjamin Franklin had long been fascinated by electricity. In the 1740s, he began conducting experiments with static electricity using glass tubes and rods. He coined terms like battery, conductor, and electrician that are still used today.

By the 1750s, Franklin theorized that lightning was a form of electricity. Other prominent scientists like Isaac Newton rejected this idea, insisting that lightning was caused by the ignition of air. Franklin was determined to prove his theory correct.

The Dangerous Kite & Key Experiment

To demonstrate that lightning was electrical, Franklin devised his dangerous kite and key experiment. In 1752, during a thunderstorm in Philadelphia, he flew a kite with a pointed wire attached to the top. On the end of the kite string, he tied a metal key.

Franklin hypothesized that the kite would collect electricity from the storm clouds, allowing him to capture a lightning bolt's electrical charge through the key. This would demonstrate that lightning was electrical.

Conducting the Risky Experiment

Franklin recruited his 21-year-old son, William, to help him conduct the hazardous experiment. William flew the kite while Franklin stood in a shed for shelter, holding the kite string with the key attached.

As the storm picked up, Franklin noticed the loose fibers on the string begin to stand upright, as static electricity made their way downwards. He then noticed a pulse of static discharge leap from the key to his knuckle. At that moment, he had proof that lightning was electrical.

Revolutionary Impact on Understanding Electricity

Franklin's kite experiment provided concrete evidence that lightning was electrical, not ignited air as was commonly believed. This discovery revolutionized our understanding of electricity and lightning.

Some key impacts of Franklin's experiment include:

Dangers and Controversies of the Experiment

While highly significant, Franklin's kite experiment was extremely dangerous and remains controversial to this day. Some key dangers and controversies include:

Franklin's Later Innovations in Electricity

After his kite experiment, Franklin continued his pioneering research into electricity. Some of his major later contributions include:

Franklin's electrical experiments and innovations fundamentally advanced human understanding of electricity in the 18th century. He was truly one of the most influential early electrical scientists.


In conclusion, Benjamin Franklin's revolutionary kite and key experiment in 1752 provided concrete proof that lightning was electrical. This discovery transformed scientific understanding of electricity and inspired Franklin's later innovations like the lightning rod. While highly significant, the kite experiment was also quite dangerous and faces skepticism from some modern scientists. Nonetheless, it remains one of the most famous scientific experiments in history and demonstrated Franklin's daring scientific empiricism.