Electricity was on people's minds in the 1740s, but not in the way we think about it today. People used electricity for magic tricks by creating sparks and shocks. Scientists conducted experiments with electricity, but scientific thinking about electricity had not changed much in hundreds of years. Electricity wasn't "useful" yet.
Benjamin Franklin was interested in electricity. Being a curious and inventive thinker, Franklin wanted to know more than just the popular tricks. He kept thinking about electricity and came up with a very important idea.
His idea was about electricity and lightning. Franklin noticed several similarities between the two: They both created light, made loud crashes when they exploded, were attracted to metal, had a particular smell, and more. Based on these observations, Franklin thought electricity and lightning were the same thing. A few people shared his belief, but no one had ever tested it.
Franklin wrote up his thoughts on electricity in several letters to a fellow scientist who lived in London. This scientist and other scientists in London thought Franklin's letters contained valuable information, so in 1751 they published them in a little book, Experiments and Observations on Electricity.
One of the letters contained Franklin's plan for how to prove that electricity and lightning were the same. His plan required something tall, like a hill or a tall building, but Philadelphia had neither at the time. While Franklin was waiting for a tall building to be built, he came up with another plan. This one involved a key and a kite.
Franklin needed something to get close enough to the clouds to attract the lightning. He couldn't get up there since Philadelphia didn't have any hills or tall buildings. He did have a silk handkerchief, a couple of sticks and some string, so instead of getting himself up near the lightning, he flew a kite up to it. And it worked! Franklin and a few other scientists in Europe (who did their own experiments) proved that lightning and electricity were the same thing.
But that wasn't enough for Franklin. He believed that this knowledge should be used for practical purposes.
What could be practical about lightning? Many folks knew what wasn't practical: having your house burn down because it was struck by lightning. Franklin thought he could help. He knew that lightning usually hit the highest part of a building. He also knew that the electrical current in lightning could start a fire. So he invented the lightning rod. A lightning rod is made of metal and is attached to the highest point on a house. The lightning hits the rod instead of the house, and the electrical current from the lightning goes into the ground and leaves the house undamaged. Franklin thought the lightning rod was his most important invention.
Music: Return of the Inventor by Dhruva Aliman
https://dhruvaaliman.bandcamp.com/album/the-wolf-and-the-river
http://www.dhruvaaliman.com/
