His kite-in-a-lightning-storm experiment, and most likely after witnessing what happens to buildings that are struck by lightning.
the lightning rod
One inventor of the lightning rod was Benjamin Franklin. Another was a German priest, Diwisch. Both appear to have made their inventions in the same decade, around 1753. See "Who Really Invented The Lightning Rod?", The Electrical Review, volume 32, 10Feb1893, p.146.
1746
benjamin franklin-lightning rod
The lightning rod
Benjamin FranklinBenjamin Franklin
He wanted to see if lightning and electricity were the same.
bifocals, electricity, lightning rod, franklin stove,odometer
Lightning rod, Franklin stove, and bifocal glasses.
Lightning rod, Franklin stove, bifocals, glass harmonica
Lightning arrester or lightning rod is a rod paired with a conductor. The lightning arrester was invented by Benjamin Franklin in the late 1749.
lightning rod by Benjamin Franklin