It’s partly the way this is written, but mostly the limits of my understanding that make this excerpt from a site on lightning hard to fathom. Can someone clarify what Franklin did and how it illustrated that lightning was electricity? Exactly how was the key set-up designed to show this? What was the first experiment? It seems as if he expected lightning to go through one hand to the other hand and then to the ground. That can’t be right. Can anyone simplify these descriptions and in doing so, explain what he was looking for and how this might show it?
"While others had previously noted the similarity between laboratory sparks and lightning, Franklin was the first to design an experiment which conclusively proved the electrical nature of lightning. In his experiment, he theorized that clouds are electrically charged, from which it follows that lightning must also be electrical. The experiment involved Franklin standing on an electrical stand, holding an iron rod with one hand to obtain an electrical discharge between the other hand and the ground. If the clouds were electrically charged then sparks would jump between the iron rod and a grounded wire, in this case, held by an insulating wax candle.
This experiment was successfully performed by Thomas Francois D’Alibard of France in May 1752 when sparks were observed to jump from the iron rod during a thunderstorm. G. W. Richmann, a Swedish physicist working in Russia during July 1753, proved that thunderclouds contain electrical charge, and was killed when lightning struck him.
Before Franklin accomplished his original experiment, he thought of a better way to prove his hypothesis through the use of a kite. The kite took the place of the iron rod, since it could reach a greater elevation and could be flown anywhere. During a Pennsylvania thunderstorm in 1752 the most famous kite in history flew with sparks jumping from a key tied to the bottom of damp kite string to an insulating silk ribbon tied to the knuckles of Franklin’s hand. Franklin’s grounded body provided a conducting path for the electrical currents responding to the strong electric field buildup in the storm clouds."
I feel so close to understanding, yet so far away. Nome sane?
I’ll throw in a little detail, but I really can’t tie it all together, either. Franklin had an electrical storage device called a Leyton (Leydon?) Jar. He got a charge to come down the wet string and into the Jar. That confirmed his hunch that lightning was electricity.
Some folks will tell you that ol’ Ben invented, or discovered electricity with his dangerous stunt. No, quite a bit was known about it before Franklin’s kite. He added one step to our understanding of lightning. He figured out how to make and sell lightning rod protection systems (metal rods atop a building, connected by wires to ground, make it less likely that lightning will cause a fire.)
Our understanding of lightning is still growing. During my lifetime, the answers to the biggest questions have flipped several times. Positive to negative, or vice versa? Ground to sky, or vice versa? Does lightning jump from cloud to cloud, or is that an illusion? The answers right now go like this; + to -, or - to +? Both, often in the same strike. Up? Down? Both. Cloud to cloud? Yes, and some strikes even have huge sparks up from the top of the highest cloud as a big strike goes to ground.
I understand Leyden jars. It’s the design of the two activities that I don’t really follow and how those would answer the questions. What were these two experiments, really? I don’t follow. Any help electrodopers? xo, C.
Basically, Franklin stores some of whatever it was that flowed down the string of the kite into the Leyden jar, and then ran through a few experiments that showed that whatever was in the Leyden jar acted just like the electricity generated by other means (e.g. static discharge from rubbing glass with silk). The obvious conclusion is that the two were one and the same phenomenon.
The OP is asking for an explanation of the meaning of the following snippets from the passages he quoted:
Pertinant questions include the following:
None of that mentions Leydon jars. Is the account given simply incomplete?
What is meant by the first snippet when it says something about “holding an iron rod with one hand to obtain an electrical discharge between the other hand and the ground?” The OP wants to know what the two hands have to do with each other here. Furthermore, what does the “other hand” have to do with anything at all if the sparks are supposed to jump from the rod to a grounded wire?
What is the significance of “insulating silk ribbon tied to the knuckles of Franklin’s hand” if the current was supposed to have gone ahead and travelled through his body?
Thank you,** Frylock**. That’s exactly what I mean. I can’t figure out what the passage is trying to describe, and therefore can’t really understand how the experiments illustrated this basic fact of nature that lightning is electricity. What, exactly, did each of them illustrate? And exactly how? What did the individuals actually do, since it’s not at all clear in these descriptions - in spite of the fact that these are much more complete accounts than I’ve ever read before of these types of activities. I’d never read, for instance, that Franklin had anything tied around his hand when he did this. Any help?