Oh Ben, Go Fly a Kite

And he did. And he discovered electricity.

Yeah, sure.

Ben Franklin was an amazing person, but he really discovered a principle about lightning with that experiment. The finding was put to use in the form of an invention that makes life much safer in electrical storms. Since lightning is an electrical discharge, the discovery of the principles of 'the ground' and 'resistance' apply generally to electricity. His discovery of these 'principles of electricity' enabled us to make electricity safe and practical.

First, let's consider the historical aspect of the story. Ben Franklin tied a 'key' to a string of a kite. In today's language, we think of a 'key' as something that operates a lock. It's more likely, considering the e=mc² that it was 'the key to a gear mechanism,' or maybe the 'key to a wheel.'

What Franklin suspected and verified with that experiment was that 'lightning will seek the ground through the highest point, in its proximity, that it can strike to reach the ground with the least reistance.'

Folks, if you want to try this at home, bury the key, and DO NOT - REPEAT: DO NOT - hold the string (or light wire). You will become the least resistant course for at least some of the electricity! (If you don't bury the key, you will be 'the course of least resistance.')

An easier way to see this concept work is to watch lightning strike a lightning rod. That was what Franklin used the experiment to invent.