How Benjamin Franklin tamed lightning

In the middle of the eighteenth century, the phenomenon of electricity was still something completely new, and scientists only gradually began to understand the laws of this invisible but powerful force. Even businessman and politician Benjamin Franklin cannot escape the fascination with this mysterious medium. In many experiments, he investigates the phenomenon of charges, the transmission of electricity through conductive materials, and even develops an initial concept of the battery.

Could lightning also be an electric shock?

During his experiments, Franklin was subjected to severe electric shocks several times – and was affected by the effects of electricity. At the same time, the sparks and sensations when he was electrocuted strongly remind him of the stories of people struck by lightning. Isn’t lightning supposed to be a variety of electricity – a gigantic spark jumped from the cloud to the ground?

In 1749, Franklin described his hypothesis in a letter: “When electrified clouds pass over a country, high mountains, tall trees, tall spiers, church spiers, ship masts, chimneys, etc., they attract electric fire to themselves. To all cloud discharges There.” At first, Franklin’s idea was met with derision and laughter. This idea is very bold and strange. One does not wish to accept such a thesis without evidence.

How can this be tested?

But how do you prove that lightning and electricity are basically the same thing? After some reflection, Franklin came up with a concept—the sentry box experiment: “Put some kind of sentry box on a high tower—large enough for a man and a conductive base plate. An iron rod, sharpened at the end, protrudes about ten meters from this board,” As Franklin says, describing the structure. If the storm clouds now passed over the stick, the staff would have to draw their electric charge and electric the base plate with the guy.

But Franklin lives in Philadelphia in the eighteenth century, and in that city there were few tall buildings or hills appropriate at the time. How is he supposed to be able to get close enough to a thundercloud with the crew? In search of a solution, the amateur researcher came up with an unusual alternative: if there is no tower, then you have to approach the lightning bait from the clouds in a different way – with a kite.

Dragon Experience

On the afternoon of June 15, 1752, it was time: Benjamin Franklin conducted his daring experiment. When lightning flashes on the horizon and a dark roar announces a thunderstorm, he goes out with his son to fly a kite. A silk cloth stretched on two sticks is used as a kite. A raised iron wire is attached to the upper side of the kite, and the hemp rope serves as a leash – a conductive material when wet.

Franklin explains the principle: “As soon as the storm clouds pass over the kite, the pointed wire will draw electric flames out of it and the kite and wire will become electrified.” To avoid being struck by lightning, Franklin does not hold his kite’s hemp string directly in his hand. Instead, he tied a silk thread to its end, which he keeps dry by placing under a shelter from the rain. In this way, the silk thread acts as an insulator, preventing the direct transmission of electricity coming from the cloud.

To prove that a current was flowing, Franklin hung a switch on the end of a hemp rope. This charges and can now jump sparks on an approaching hand. The experiment succeeded. Franklin finally succeeded in asserting that lightning is nothing more than a form of electricity.

lightning bolt victory

But that’s not all, because the brilliant businessman Franklin also sees a very practical benefit in this knowledge: if an iron wire could conduct electricity from a thundercloud, could such a wire also serve as a conductor of lightning strikes? This should consist of an insulated cable with one free end stuck into the ground and the other protruding from the roof of the building to the sky. “A house so equipped will not be damaged by lightning. This is because it is attracted to the tips and pushed through the metal into the ground without damaging anything,” says Franklin, describing the principle.

As early as 1752, Franklin outfitted his home with a lightning conductor, and the first public buildings in Philadelphia received this type of lightning protection. After improving the principle further, the new lightning conductor is sold like hot cakes in neighboring regions as well as in Europe. “Mr. Franklin of Philadelphia must be congratulated for his useful discoveries in the field of electricity and for his use of pointed poles in preventing the dreadful effects of thunderstorms,” ​​says the French king.

While Franklin’s lightning rods clearly have tapered rods or wires as the final pieces, this appears to be King George III of England. Whatever the suspect. He chose to install only lightning rods on his palace – a fashion that soon spread among the king’s loyal subjects. In the colonies on the other side of the Atlantic, Franklin’s models are clearly used – also as an expression of the growing desire for independence in North America.

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