History of Lightning Studies


In ancient times, lightning was seen as a tool of the gods.In Viking legend, it was Thorís hammer striking an anvil in the sky that was responsible for lightning.For the Greeks, it was Zeus who threw lightning down to the earth.North American Indian tribes thought that lightning was produced by a mystical bird with flashing feathers whose flapping caused thunder.


Even now, hundreds of years after the first scientific work with lightning, people remain in awe of its power.In the 18th century, the first systematic scientific study of lightning was carried out by Benjamin Franklin.Before Franklinís experiments, electrical science had grown to the point of separating positive and negative charges, and had developed primitive capacitors.The sparks produced in laboratories were noted as similar to lightning, but it was Franklin who designed an experiment to prove that lightning was electrical.


Benjamin Franklin believed that clouds must be electrically charged, which would mean that lightning must also be electrical.For his first experiment, he stood on an electrical stand with an iron rod in one hand to achieve an electrical discharge between the other hand and the ground.If Franklinís belief that the clouds were electrically charged was correct, then sparks should leap between the iron rod and a grounded wire held by and insulating wax candle.This test method was published in London and performed in both England and France.Thomas Francois DíAlibard of France was the first to successfully perform this experiment in May of 1752, when sparks were seen jumping from the iron rod during a thunderstorm.


Benjamin Franklin's Key Experiment

Image taken from: http://www.thebakken.org/electricity/Franklin-kite-experiment.html


Before Benjamin Franklin achieved results from his first experiment, he devised a better way of testing his hypothesis.This new experiment was his infamous kite experiment.The kite replaced the iron rod, as it could reach a higher elevation.In 1752 Franklin found success during a Pennsylvania thunderstorm.When a storm cloud passed over his kite, sparks flew from a key tied to the bottom of the damp kite string.He was also able to collect a charge on a Leyden Jar, which was a simple capacitor, that was connected to the key via a thin metal wire.Using this he was able to determine that the charge was negative.Franklin was not affected by the charges thanks to an insulating dry silk ribbon that connected the kite string to Franklinís hand.Upon reaching out to touch the key, the negative charges were attracted so strongly to the positive charges in his body that a spark jumped to Franklinís hand.†† Many who have attempted to duplicate Franklinís experiment have died trying.






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