“Why did Ben Franklin invent the lightning rod and how does the lightning rod work? And why in the world would it scare or offend anyone? Watch the video and find out!”
How could the lightning rod terrify and offend people? It is just a piece of metal connected by a wire to the ground! Well, I’ll tell you and along the way I will talk about: how the lightning rod was invented because of a misunderstanding, irritating lightning bells, a terrible earthquake, a Franklin chamber pot and how dangerous it was to ring church bells. Ready? Lets go.
The lightning rod was invented by Benjamin Franklin because he got a little bit confused. Franklin had been playing with electricity for 3 years, ever since his friend had sent him an article about strange electrical tricks he could perform. Franklin wrote back with letters of thanks and his theories on electricity. For several years, Franklin had been writing about his theory that lightning was the same as the sparks he was getting at home but on a bigger scale. He was not the first person to have that thought, but he was the first person to think of ways to experimentally prove it!
Franklin started by building a model of an electrically charged cloud. Now he couldn’t make a thundercloud in a room, but he wanted to make object that he could hang off that ground and could contain a lot of charge, irrespective of if it looked cloud-like. Therefore he made a thin cardboard tube 10 feet long and 1 foot wide that was coated in gold hung it with silk chords and charged up with his spinning static electric machine. If he approached the charged “cloud” with a blunt instrument the cloud would discharge with a loud crack and a flash. If he approached with a thin tapered needle, the spark would be less dramatic.
He then turned the experiment around. This time, he had one person hold a thin metal needle close to the cloud before he charged up the cloud. When he ran the static electricity machine, the stick would get a steady stream of quiet sparks and he could not charge up his cloud. Extrapolating to nature, Franklin decided that he could use a pointed metal stick to prevent clouds from becoming electric and creating lightning strikes IN THE FIRST PLACE! Franklin said that “rods of iron connected with wire down the outside of the building to the ground would draw the electrical fire silently out of a cloud and thereby secure us from that most sudden and terrible mischief of lightning.”
It was because of his theory that one could safely drain lightning clouds of electricity that Franklin came up with a way to prove it where you put a metal pole with a kink in it on an insulating stand in a little box (so that everything stays dry) and when an electrified thundercloud passes by the pole will get electrified too! As electricity tends to collect at points or kinks, one can get sparks from the kink in the pole! A man named Thomas Dalibard actually successfully did this in France in May of 1752! Franklin planned on attempting this experiment by putting a pole in the steeple of a church but the construction of the church was going slowly. So, a month after Dalibard did his experiment in France, Franklin flew a kite with a metal pole in it tied with a wire to a key! Franklin and Dalibard knew they weren’t getting struck by lightning but they mistakenly thought that the electricity from the cloud was “silently draining” into the pole or the key. In fact, the electric charges were stuck in the cloud, however, the charges in the metal rod or kite were repelled by the cloud and moved by induction (or moving charges at a distance) to the kink in the rod or the key. Watching the sparks stream out of a pole due to a distant thundercloud seemed to verify Franklin’s prediction that a rod connected with wire to the ground would reduce the chances of lightning strikes. In fact, when Dalibard wrote about the success of his lightning experiments he ended with the thought that “Perhaps no more than a hundred iron rods would be necessary to preserve the whole city of Paris from lightning.”
Despite the fact that the original motivation was flawed, the lightning rod that we use today is basically as Franklin designed it originally: an iron rod connected to the ground with a wire! However, it never worked to drain the electricity “silently” from a thundercloud. Why not? Well, it is because a thundercloud is farther up in the sky than Franklin realized. For electricity to jump the gap between the clouds and items on a building on the ground they must have tremendous charge, which means they strike with terrible power. So, if the lightning rod doesn’t work why do we use it? Well, it doesn’t work to prevent lightning strikes from happening, but it does keep them from their “terrible mischief”. This is because electricity flows easily through metal but doesn’t travel easily through wood or glass or brick. When lightning strikes a lightning rod the electricity safely and easily flows through the wire and into the ground. After a few years, Franklin realized this advantage of Lightning Rods, writing Dalibard that “pointed rods erected on buildings and connected with wire with the earth, would either prevent a stroke of lightning, or if not prevented, would conduct it so that the that building should suffer no damage.”
Back in 1752, two months after his kite experiment Franklin constructed a lightning rod on his house with a small gap with bells and a clapper to warn him when the rod was electrified. Supposedly, Franklin’s wife Deborah was not fond of the bells and asked how to keep them from ringing all night when he was off on his many travels. Franklin also installed lightning rods without bells at the church at the University of Pennsylvania and in the Pennslyvania State House
By the next year he published in his “Poor Richard’s Almanac” the details how to “secure buildings from mischief by thunder and lightning [with] a small iron rod.” In South Carolina a doctor managed to recreate Franklin’s kite experiment but was restrained from installing a lightning rod by his nervous neighbors. Why were they scared of a rod of metal?
Well, the first and most powerful reason was religious. Lightning was God’s judgment on man – it was the height of hubris to get in the way of God’s plan. Franklin tried to quiet their nerves by saying that “surely the thunder of heaven is no more supernatural than the rain or sunshine of heaven” and there are no qualms about roofs or umbrellas!
That did not quell the anxiety. France’s leading expert in electricity named Abbe Nollet (he was mentioned a lot in the last video) said it was, “as impious to ward off Heaven’s lightnings as for a child to ward off the chastening rod of its father.” In 1755, a terrible and unusual earthquake hit Boston and a reverend blamed it on the, “iron points invented by the “clever” Mr. Franklin.” He wailed “Oh! There is no getting out of the mighty hand of God.” (by the way, lightning rods do not cause earthquakes)
Ironically, as churches tended to be the tallest buildings at the time, and with a nice pointy cross on top, they were often the most struck by lightning often leaving say a house of ill repute nearby untouched! Ringing bells was supposed to help but just tended to be dangerous for the bell ringer. For example, in Germany over the course of just 33 years, around 400 Church towers were struck and 120 bell ringers were killed!
Over the following decades there was continual debate, riots and even battles in the courts over Franklin’s “heretical rod”. However, the fight against the lightning rod was a losing battle, as the lightning rod works and works well. Towers that were destroyed multiple times a year never had a problem again once they installed a piece of metal. Still, the battle over lightning rods (sometimes called “Franklin rods”) continued well into the 1780s!
Franklin never tried to make a penny off of his many inventions, including the lightning rod. Because of this and his charm and wit, most people from every level of society loved and admired Benjamin Franklin in a way that hasn’t been recreated since Albert Einstein, if at all! People fawned over him and had his image on every item imaginable. Supposedly, the king of France became so irritated with hearing his mistress gush over Franklin that he gave her a chamber pot with Franklin’s image on the bottom! Twenty years after Franklin’s death John Adams, a man who personally disliked Franklin, wrote that, “the invention of the lightning rod was one of the most sublime that ever entered a human imagination,” and that Franklin’s, “reputation was more universal than that of Leibnitz or Newton or Frederick or Voltaire, and his character more beloved and esteemed than any or all of them… there was scarcely a peasant or a citizen who was not familiar with [him], and who did not consider him as a friend to human kind.”
Franklin became a little distracted from his electricity studies in the 1760s and 70s by the American Revolution! In fact, all of Europe and America seemed to be focused on politics and revolution. “Electricity parties” went out of fashion and for the next 30 years aside from more people accepting lightning rods (and a man named Coulomb finding a law for the electric force) very little was discovered with electricity. That all changed in 1791, when an Italian anatomy professor happened to put a dissected frog near a static electricity machine in arguably the most important experiment of all time.
How a twitching dead frog led to the battery is next time in “The Secret History of Electricity”
Thanks for watching my video. If you haven’t seen it already I recommend watching my previous video on the true story of Ben Franklin and his kite. Also, the next story about how a dead frog led to the battery is one of my favorites of the entire history of electricity! Don’t miss it. Either way, join my youtube channel “Kathy loves Physics” or my facebook page “Kathy Loves Physics”