Benjamin Franklin (1706-1790)

4.9

Benjamin Franklin (1706-1790) was an American printer, author, publisher and scientist. He was born in Boston, Massachusetts, on January 17, 1706. His father was a maker of soap and candles.

From his school days Benjamin Franklin was greatly interested in science. In those days Leyden made his famous jar and Franklin very quickly understood that it could keep electricity.

He invented a way of drawing the electric fire from the clouds by rods of iron on high buildings. He had invented the lightning-rod.

In June 1752 he risked his life and the life of his son William, who helped him to prove that lightning is an electrical discharge. They made a kite of silk on a wooden frame with a string of metal wire.

Standing in the open door of their house they flew it in a thunder-storm, when the rain was falling.

At first nothing happened but as the kite string got wet from the rain, electricity began to flow. Sparks jumped between the key and the Leyden jar. The electric current could not flow along the kite string till it got wet. Wet silk, like metal, is a good conductor of electricity. Dry silk is a non-conductor. Benjamin Franklin’s lightning conductor is now used all over the world. He also invented many of the terms which are still used in electricity (battery, semiconductor, etc.).