Monday, June 10, 2013

How Ben's Kite Probably Won the Revolution

Most illustrations of the famous kite fly get it wrong--Ben out doors, the lightning actually striking the kite, his soon William either absent or depicted as a small boy.  This one gets most of it right as Ben and his 19 year old son seek shelter from the rain in a shed.  The only err in this one is Franklin is holding the wet string above the key, not by the dry ribbon below it.  William holds the Lyden Jar which is charged by electrical discharges from the clouds, not by a direct lightning strike of h


Like a youthful George Washington chopping down the cherry tree, Benjamin Franklin flying the kite in the lightening storm is an image known to every school child.  Unlike the cherry tree myth, Franklin really did fly a kite in a storm on June 10, 1752. 
It was the most spectacular of the Philadelphia sage’s experiments with electricity which earned him world wide acclaim as a scientist.  The adventure would also have world-wide political implications. 
Born in Boston in 1707, Franklin’s amazing career is too rich and varied to recount here.  Suffice it to say after Franklin arrived in Philadelphia as a 17 year old run-away apprentice in 1723 he was a printer, writer, author, editor, and  publisher; businessman; post master; local official; militia officer; inventor; scientist, philanthropist, founder of the first insurance company, fire brigade, and hospital in the colonies; founder of the University of Pennsylvania and the American Philosophic Society; colonial agent in Britain; delegate to the Continental Congress and member of the committee which drafted the Declaration of Independence; diplomat and Minister to France; President of Pennsylvania, and member of the Constitutional Convention.  Whew! And that leaves out a lot. 
By 1752 Franklin was semi-retired from his successful printing businesses and focusing his attention on his electrical experiments.  Franklin, experimenting with a Lyden Jar, a container for storing an electrical charge, had already proven the existence of positive and negative electrical charges and shown them to both be forms of the same “electrical fluid.”  He had also described conservation of a charge.  These were critical advances in scientific learning. 
In 1750 he published a paper describing a kite experiment to show conclusively that lighting as a form of electrical discharge. Adapting his experiment to an iron rod instead of a kite Frenchman Thomas-Fran├žois Dalibard succesfully proved Franklin’s hypothesis in May 1752. 
Of course Franklin would have no way of knowing that when he took his son and faithful assistant William out to an open area near the edge of the city that day to finally execute the experiment himself.  Under threatening skies he attached his kite to a silk string, tying an iron key at the other end.  A thin wire was wound around the key run into a Leyden jar.  A silk ribbon was tied to the key for Franklin to hold.
He launched the kite as the storm approached and once it was aloft, moved under the cover of a barn so that he would not get wet. As the thunder storm cloud passed over Franklin’s kite, negative charges in the cloud passed onto his kite, down the wet silk string, to the key, and into the jar. Franklin, standing on dry ground inside the barn and holding the dry ribbon was insulated from the negative charges on the key.  When he moved his free hand near the iron key, a spark jumped from the key to his exposed knuckle because the negative charges in the key were so strongly attracted to the positive charges in his body.
He had successfully shown that lightning was static electricity.  Franklin was lucky to have survived the experiment.  Others who tried to duplicate it were electrocuted, including noted Russian scientist Georg Wilhelm Richmann.  Franklin would have died too, had lightning actually struck the kite.  He was aware of that danger.  Which is why he flew his kite early in the storm close to the clouds where it picked up electrical discharges without actually being struck by lightning. 
A supremely practical man, he quickly turned his discovery to use with the invention of the lighting rod which protected buildings from deadly lightning strikes which every year were responsible for many fires and deaths. 
His findings made him one of the most famous men in the world.  The prestigious Royal Society awarded him its Copley Medal in 1753 and elected him a Fellow of the Society, an honor granted to few Colonials, in 1756.  Franklin also did pioneering work on the wave theory of light, meteorology, cooling by evaporation, heat conductivity, and oceanography over his long life. 
Franklin’s fame as a scientist and as the author of pithy sayings in his famous Poor Richard’s Almanac, opened many important doors for him when he became agent for Pennsylvania and other colonies in London from 1757 to 1775.  When he arrived in France as American Minister in 1776, he found himself the object of public adoration and private respect due in no small measure to his enormous scientific reputation.  With an in to the great Salons of Paris he carefully exploited his fame and cultivated relationships that would pay off for the struggling new nation first with significant loans, then with official recognition, and finally with French troops on the ground and a fleet off shore that bottled up unfortunate General Cornwallis  and the main British Army at Yorktown. 
A good case for that can be made that it was all due to that George Washington owed his most famous battle field victory to that dangerous experiment in 1752.


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