Kite experiment

An artistic rendition of the kite experiment by Benjamin West.

The kite experiment was a scientific experiment proposed and later conducted by Benjamin Franklin with assistance from his son William Franklin. The experiment's purpose was to uncover then unknown facts about the nature of lightning and electricity.

Background

In 1750 the electrical nature of lightning was the subject of public discussion in France, with a dissertation of Denis Barbaret receiving a prize in Bordeaux; Barbaret proposed a cause in line with the triboelectric effect. The physician Jacques de Romas also wrote a memoir that year with similar ideas. Franklin had listed a dozen analogies between lightning and electricity in his notebooks at the end of 1749. Speculations of Jean-Antoine Nollet had led the issue being posed as a prize question at Bordeaux in 1749. De Romas later defended his own electrical kite proposal as independent of Franklin's.

Lightning rod experiments

In 1752, Franklin proposed an experiment with conductive rods being used to attract lightning to a Leyden jar, an early form of capacitor.

Such an experiment was carried out in May 1752 at Marly-la-Ville in northern France. The experimenter was Thomas-François Dalibard. An attempt to replicate the experiment killed Georg Wilhelm Richmann in Saint Petersburg in August 1753, thought to be the victim of ball lightning. Franklin himself conducted the experiment in June 1752, supposed to be executed on the top of the spire on Christ Church in Philadelphia.

Kite experiment

Franklin realized the dangers of using conductive rods and instead used a kite. The increased height allowed him to stay on the ground and the kite was less likely to electrocute him. According to the legend, Franklin kept the string of the kite dry at his end to insulate him while the rest of the string was allowed to get wet in the rain to provide conductivity. A key was attached to the string and connected to a Leyden jar, which Franklin assumed would accumulate electricity from the lightning. The kite wasn't struck by visible lightning (had it done so, Franklin would almost certainly have been killed^{[citation needed]}), but Franklin noticed the strings of the kite were repelling each other and deduced that the Leyden jar was being charged. Franklin reportedly received a mild shock by moving his hand near the key afterwards, because as he had estimated, lightning had negatively charged the key and the Leyden jar, proving the electric nature of lightning

Fearing that the test would fail or that he would be ridiculed, Franklin took only his son to witness the experiment with himself and published the accounts of the test in third person.

De Romas pursued his priority claim to the kite experiment. He had it recognised by the Bordeaux Academy, and then the Académie française in Paris.

Modern Controversy

There is some degree of doubt now placed on whether or not Franklin actually performed this experiment. According to Tom Tucker author of "Bolt of Fate: Benjamin Franklin and His Electric Kite Hoax", "There was no witness identified in the announcement, no location named—and nowhere does Franklin say he actually performed the experiment." Tucker attempted to recreate the experiment and was unsuccessful.

In one episode of the television series MythBusters the hosts tried to emulate components of this famous experiment and consequently declared the myth "busted".^{[citation needed]}

External links

• Philosophical Transactions: A Letter of Benjamin Franklin, Esq; to Mr. Peter Collinson, F. R. S. concerning an Electrical Kite. Phil. Trans. 1751–1752 47, 565–567; (PDF)