I often watch classes from the Great Courses, the most recent is entitled “Understanding the Misconceptions of Science.” In the lecture “Franklin’s Kite and Other Electrifying Myths”, the instructor describes the fallacy behind Benjamin Franklin and his kite, a story that demonstrates the power of electricity. The kite was made with two light strips of cedar wood big enough to span a large silken handkerchief. It was then tied to a hemp string, which was tied to a key. A metal rod was extended from the top of the kite to attract electricity. This design was the progenitor for his idea of a lightning rod, which Franklin is credited with inventing. Finally, a silk ribbon was tied to the string. Franklin supposedly stood under cover, keeping himself and the silk ribbon dry. This was important to keep electricity from conducting through the silk and into his hand. According to the legend, Franklin flew the kite into a thundercloud, but before the rain started, he supposedly moved his hand near the key and a spark jumped from the key to his knuckle. Furthermore the little strands on the twine stood up like the hair on your arm might when you take off a fuzzy sweater. However, the largely believed legend is that the kite was struck by lightning, a lightning bolt came down the string, jumped off the key, and was collected in a glass and metal contraption called a Leyden jar which was used a that time to store electricity. The big problem is what would happen if lightning actually did strike the kite as the story is told: that amount would have simply killed Franklin. Lightning doesn’t just flow down a string and stop. Electricity has to flow from place to place, and the lightning would have tried somehow to get from the string to the earth, and the easiest path would have been through the silk ribbon and ultimately Ben Franklin. However, Franklin did advance the technology of lightning rods, which are pointy pieces of metal that lightning prefers to hit rather than a house.
The mechanism of lightning initiation remains a mystery, primarily because it usually occurs deep inside the cloud. Most researchers agree that it must involve the creation in the cloud of an elongated ionized region (“lightning seed”) of about 10 m or more in length that is capable of locally enhancing the electric field at its extremities. Such field enhancement is the main prerequisite for the formation of a hot, self-propagating lightning leader channel. The leader is expected to be bidirectional, although its positive and negative ends may behave differently. Most of the time, bidirectional leaders are completely or in part hidden inside the cloud, which makes their optical imaging impossible. We do know that lightning starts with a branching bundle of charge—the leader---descending from the cloud. It spreads downward at speeds of tens to hundreds of kilometers per second, covering a few kilometers to the ground in a few dozen milliseconds. Once the leader makes contact with the ground, the cloud and ground equalize with a massive discharge of more than 20,000 amps. This is the blinding flash you see.
Lightning is one of the earliest forms of electricity known to mankind, mysterious and sometimes fascinating and frightening. The temperature of a lightning bolt is more than 50,000 degrees F. six times hotter than that of the surface of the sun. All that is because of the unaccounted flow of electrons being forced to move. At this stage,it is a movement of electricity from one space to another. Going one step further closer – in fact much closer- is to realize that our own human body produces electricity. A heart beats because every moment electrical impulses, spread through the heart muscle triggering the movement. The doctors measure these by electrocardiogram.
Electricity is nothing but the flow of current- Flow of current is nothing but, the flow of electrons. All of the materials we see in this world are made up of atoms – be it metals. liquids or gases. It means if you can keep on breaking up any materials, you would finally end up with the tiniest particle called an atom. We know that every material in this world is made up of atoms – our body is made up of atoms. They are so minute and minuscule that our naked eye is not able to see them.
If you are caught in a thunderstorm run for your car—it is the safest place to be. The automobile body, however, must be metallic to conduct electricity to ground. A car or mobile home made from fiberglass will not serve the same purpose.
Max Sherman is a medical writer and pharmacist retired from the medical device industry. His new book “Science Snippets” is available from Amazon and other book sellers. It contains a number of previously published columns. He can be reached by email at [email protected].