The kite experiment is a scientific experiment in which a

kite A kite is a tethered heavier-than-air or lighter-than-air craft with wing surfaces that react against the air to create lift and drag forces. A kite consists of wings, tethers and anchors. Kites often have a bridle and tail to guide the fac ...

with a pointed, conductive wire attached to its apex is flown near thunder clouds to collect electricity from the air and conduct it down the wet kite string to the ground. It was proposed and may have been conducted by

Benjamin Franklin Benjamin Franklin ( April 17, 1790) was an American polymath who was active as a writer, scientist, inventor, statesman, diplomat, printer, publisher, and political philosopher. Encyclopædia Britannica, Wood, 2021 Among the leading inte ...

with the assistance of his son

William Franklin William Franklin (22 February 1730 – 17 November 1813) was an American-born attorney, soldier, politician, and colonial administrator. He was the acknowledged illegitimate son of Benjamin Franklin. William Franklin was the last colonial G ...

. The experiment's purpose was to uncover the unknown facts about the nature of

lightning Lightning is a naturally occurring electrostatic discharge during which two electrically charged regions, both in the atmosphere or with one on the ground, temporarily neutralize themselves, causing the instantaneous release of an avera ...

and

electricity Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as describ ...

, and with further experiments on the ground, to demonstrate that lightning and electricity were the result of the same phenomenon.

Background

Speculations of

Jean-Antoine Nollet Jean-Antoine Nollet (; 19 November 170025 April 1770) was a French clergyman and physicist who did a number of experiments with electricity and discovered osmosis. As a deacon in the Catholic Church, he was also known as Abbé Nollet. Biography ...

had led to the issue of the electrical nature of lightning being posed as a prize question at Bordeaux in 1749. In 1750, it was the subject of public discussion in France, with a dissertation of Denis Barberet receiving a prize in

Bordeaux Bordeaux ( , ; Gascon oc, Bordèu ; eu, Bordele; it, Bordò; es, Burdeos) is a port city on the river Garonne in the Gironde department, Southwestern France. It is the capital of the Nouvelle-Aquitaine region, as well as the prefect ...

; Barberet proposed a cause in line with the triboelectric effect. The same year, Franklin reversed his previous skepticism of electrical lightning's attraction to high points. The physicist Jacques de Romas also wrote a

mémoire In French culture, the word ''mémoire'', as in un mémoire ("a memory" – indefinite article), reflects the writer's own experiences and memories. The word has no direct English translation. Up to the 18th century The word appeared in the course ...

with similar ideas that year, and later defended them as independent of Franklin's.

Lightning rod experiments

In 1752, Franklin proposed an experiment with

conductive In physics and electrical engineering, a conductor is an object or type of material that allows the flow of charge (electric current) in one or more directions. Materials made of metal are common electrical conductors. Electric current is gene ...

rods to attract lightning to a

leyden jar A Leyden jar (or Leiden jar, or archaically, sometimes Kleistian jar) is an electrical component that stores a high-voltage electric charge (from an external source) between electrical conductors on the inside and outside of a glass jar. It typ ...

, an early form of

capacitor A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals. The effect of ...

. Such an experiment was carried out in May 1752 at

Marly-la-Ville Marly-la-Ville () is a commune in the Val-d'Oise department in Île-de-France in northern France, 25 km north of Paris. History Thomas-François Dalibard lived at 15 rue du Colonel Fabien, a classical eighteenth-century mansion. He was a n ...

in northern France by

Thomas-François Dalibard Thomas-François Dalibard (born in Crannes-en-Champagne, France in 1709, died in 1778) was a French physicist who performed the first lightning rod experiment. He was married to the novelist and playwright Françoise-Thérèse Aumerle de Saint- ...

. An attempt to replicate the experiment killed

Georg Wilhelm Richmann Georg Wilhelm Richmann () (22 July 1711 – 6 August 1753), (Old Style: 11 July 1711 – 26 July 1753) was a Russian Imperial physicist of Baltic German descent. Richmann did pioneering work on electricity, atmospheric electricity, and calorimetr ...

Saint Petersburg Saint Petersburg ( rus, links=no, Санкт-Петербург, a=Ru-Sankt Peterburg Leningrad Petrograd Piter.ogg, r=Sankt-Peterburg, p=ˈsankt pʲɪtʲɪrˈburk), formerly known as Petrograd (1914–1924) and later Leningrad (1924–1991), i ...

in August 1753; he was thought to be the victim of

ball lightning Ball lightning is a rare and unexplained phenomenon described as luminescent, spherical objects that vary from pea-sized to several meters in diameter. Though usually associated with thunderstorms, the observed phenomenon is reported to last ...

. Franklin himself is said to have conducted the experiment in June 1752, supposedly on the top of the spire on Christ Church in Philadelphia. However, the spire at Christ Church was not added until 1754.

Franklin's kite experiment

Franklin's kite experiment was performed in Philadelphia in June 1752, according to the account by Priestley. Franklin described the experiment in the ''

Pennsylvania Gazette ''The Pennsylvania Gazette'' was one of the United States' most prominent newspapers from 1728 until 1800. In the several years leading up to the American Revolution the paper served as a voice for colonial opposition to British colonial rule, ...

'' in October 19, 1752, without mentioning that he himself had performed it. This account was read to the Royal Society on December 21 and printed as such in the ''Philosophical Transactions''. A more complete account of Franklin's experiment was given by

Joseph Priestley Joseph Priestley (; 24 March 1733 – 6 February 1804) was an English chemist, natural philosopher, separatist theologian, grammarian, multi-subject educator, and liberal political theorist. He published over 150 works, and conducted exp ...

in 1767, who presumably learned the details directly from Franklin, who was in London at the time Priestley wrote the book.National Archives
The Kite Experiment, 19 October 1752
Retrieved February 6, 2017 BEP-JONES-Franklin and Electricity

According to the 1767 Priestley account, Franklin realized the dangers of using conductive rods and instead used the conductivity of a wet hemp string attached to a

. This allowed him to stay on the ground while his son assisted him to fly the kite from the shelter of a nearby shed. This enabled Franklin and his son to keep the silk string of the kite dry to insulate them while the hemp string to the kite was allowed to get wet in the rain to provide conductivity. A house key belonging to

Benjamin Loxley Benjamin Loxley, also known as Benjamin Lockley (December 20, 1720 – October 10, 1801) was a Philadelphia carpenter-architect, master builder, investor and military leader in the American Colonial Period. He began his career by working as a ca ...

was attached to the hemp string and connected to a

Leyden jar A Leyden jar (or Leiden jar, or archaically, sometimes Kleistian jar) is an electrical component that stores a high-voltage electric charge (from an external source) between electrical conductors on the inside and outside of a glass jar. It typ ...

; a silk string was attached to this. "At this key he charged phials, and from the electric fire thus obtained, he kindled spirits, and performed all other electrical experiments which are usually exhibited by an excited globe or tube." The kite was not hit by visible lightning; had it been, Franklin would almost certainly have been killed. However, Franklin did notice that loose threads of the kite string were repelling each other and deduced that the Leyden jar was being charged. He moved his hand near the key and observed an electric spark, proving the electric nature of lightning.

''The Pennsylvania Gazette''s account

The kite experiment was described in ''The Pennsylvania Gazette'' on October 19, 1752 as follows:

References

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)
*http://www.pbs.org/benfranklin/shocking/ {{Benjamin Franklin Benjamin Franklin Physics experiments Electricity Lightning 1750s in science Kites