The kite experiment is a scientific experiment in which a kite with a pointed conductive wire attached to its apex is flown near thunder clouds to collect static electricity from the air and conduct it down the wet kite string to the ground. The experiment was first proposed in 1752 by Benjamin Franklin, who reportedly conducted the experiment with the assistance of his son William. The experiment's purpose was to investigate the nature of lightning and electricity, which were not yet understood. Combined with further experiments on the ground, the kite experiment demonstrated that lightning and electricity were the result of the same phenomenon.
Speculations of Jean-Antoine Nollet 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. 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. [1] The physicist Jacques de Romas also wrote a mémoire with similar ideas that year and later defended them as independent of Franklin's. [2]
In 1752, Franklin proposed an experiment with conductive rods 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, by Thomas-François Dalibard. [3] An attempt to replicate the experiment killed Georg Wilhelm Richmann in Saint Petersburg in August 1753; he was thought to be the victim of ball lightning. [4] 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. [5]
Franklin's kite experiment was performed in Philadelphia in June 1752, according to the account by Joseph Priestley. [6] Franklin described the experiment in the Pennsylvania Gazette on October 19, 1752 [7] [8] without mentioning that he had performed it. [9] The account was read to the Royal Society on December 21 and printed as such in the Philosophical Transactions. [6] A more complete account of Franklin's experiment was given by Priestley in 1767, who presumably learned the details directly from Franklin, who was in London while Priestley wrote the book. [6]
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 kite. As a result, he was able to remain on the ground and let his son fly the kite from the cover of a shed close by. That 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 was attached to the hemp string and connected to a Leyden jar; a silk string was attached to that. "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." Contrary to popular belief, the kite was not hit by visible lightning; otherwise Franklin would almost certainly have been killed. [10] [11] [12] However, Franklin noticed that loose threads of the kite string were repelling one another and deduced that the Leyden jar was being charged. He moved his hand near the key and observed an electric spark, [6] which proved the electric nature of lightning. [13]
Benjamin Franklin was an American polymath: a leading writer, scientist, inventor, statesman, diplomat, printer, publisher and political philosopher. Among the most influential intellectuals of his time, Franklin was one of the Founding Fathers of the United States; a drafter and signer of the Declaration of Independence; and the first postmaster general.
Electric charge is the physical property of matter that causes it to experience a force when placed in an electromagnetic field. Electric charge can be positive or negative. Like charges repel each other and unlike charges attract each other. An object with no net charge is referred to as electrically neutral. Early knowledge of how charged substances interact is now called classical electrodynamics, and is still accurate for problems that do not require consideration of quantum effects.
A Leyden jar is an electrical component that stores a high-voltage electric charge between electrical conductors on the inside and outside of a glass jar. It typically consists of a glass jar with metal foil cemented to the inside and the outside surfaces, and a metal terminal projecting vertically through the jar lid to make contact with the inner foil. It was the original form of the capacitor.
Timeline of electromagnetism and classical optics lists, within the history of electromagnetism, the associated theories, technology, and events.
Georg Wilhelm Richmann was a Russian physicist of Baltic German origin who did pioneering work on electricity, atmospheric electricity, and calorimetry. He died by electrocution in St. Petersburg when struck by apparent ball lightning produced by an experiment attempting to ground the electrical discharge from a storm.
Atmospheric electricity describes the electrical charges in the Earth's atmosphere. The movement of charge between the Earth's surface, the atmosphere, and the ionosphere is known as the global atmospheric electrical circuit. Atmospheric electricity is an interdisciplinary topic with a long history, involving concepts from electrostatics, atmospheric physics, meteorology and Earth science.
Fluid theories of electricity are outdated theories that postulated one or more electrical fluids which were thought to be responsible for many electrical phenomena in the history of electromagnetism. The "two-fluid" theory of electricity, created by Charles François de Cisternay du Fay, postulated that electricity was the interaction between two electrical 'fluids.' An alternate simpler theory was proposed by Benjamin Franklin, called the unitary, or one-fluid, theory of electricity. This theory claimed that electricity was really one fluid, which could be present in excess, or absent from a body, thus explaining its electrical charge. Franklin's theory explained how charges could be dispelled and how they could be passed through a chain of people. The fluid theories of electricity eventually became updated to include the effects of magnetism, and electrons.
Electrochemistry, a branch of chemistry, went through several changes during its evolution from early principles related to magnets in the early 16th and 17th centuries, to complex theories involving conductivity, electric charge and mathematical methods. The term electrochemistry was used to describe electrical phenomena in the late 19th and 20th centuries. In recent decades, electrochemistry has become an area of current research, including research in batteries and fuel cells, preventing corrosion of metals, the use of electrochemical cells to remove refractory organics and similar contaminants in wastewater electrocoagulation and improving techniques in refining chemicals with electrolysis and electrophoresis.
An electric spark is an abrupt electrical discharge that occurs when a sufficiently high electric field creates an ionized, electrically conductive channel through a normally-insulating medium, often air or other gases or gas mixtures. Michael Faraday described this phenomenon as "the beautiful flash of light attending the discharge of common electricity".
Thomas-François Dalibard was a French physicist who performed the first lightning rod experiment. He was married to the novelist and playwright Françoise-Thérèse Aumerle de Saint-Phalier.
The history of electromagnetic theory begins with ancient measures to understand atmospheric electricity, in particular lightning. People then had little understanding of electricity, and were unable to explain the phenomena. Scientific understanding and research into the nature of electricity grew throughout the eighteenth and nineteenth centuries through the work of researchers such as André-Marie Ampère, Charles-Augustin de Coulomb, Michael Faraday, Carl Friedrich Gauss and James Clerk Maxwell.
Ebenezer Kinnersley was an English scientist, inventor and lecturer, specializing in the investigation of electricity.
A global atmospheric electrical circuit is the continuous movement of atmospheric charge carriers, such as ions, between an upper conductive layer and surface. The global circuit concept is closely related to atmospheric electricity, but not all atmospheres necessarily have a global electric circuit. The basic concept of a global circuit is that through the balance of thunderstorms and fair weather, the atmosphere is subject to a continual and substantial electrical current.
The History and Present State of Electricity (1767), by eighteenth-century British polymath Joseph Priestley, is a survey of the study of electricity up until 1766, as well as a description of experiments by Priestley himself.
A lightning rod or lightning conductor is a metal rod mounted on a structure and intended to protect the structure from a lightning strike. If lightning hits the structure, it is most likely to strike the rod and be conducted to ground through a wire, rather than passing through the structure, where it could start a fire or even cause electrocution. Lightning rods are also called finials, air terminals, or strike termination devices.
Franklin bells are an early demonstration of electric charge designed to work with a Leyden jar or a lightning rod. Franklin bells are only a qualitative indicator of electric charge and were used for simple demonstrations rather than research. The bells are an adaptation to the first device that converted electrical energy into mechanical energy in the form of continuous mechanical motion: in this case, the moving of a bell clapper back and forth between two oppositely charged bells.
Franklin's electrostatic machine is a high-voltage static electricity-generating device used by Benjamin Franklin in the mid-18th century for research into electrical phenomena. Its key components are a glass globe which turned on an axis via a crank, a cloth pad in contact with the spinning globe, a set of metal needles to conduct away the charge developed on the globe by its friction with the pad, and a Leyden jar – a high-voltage capacitor – to accumulate the charge. Franklin's experiments with the machine eventually led to new theories about electricity and inventing the lightning rod.
Jacques de Romas was a French physicist.
Georg Matthias Bose, also known as Mathias Bose, was an electrical experimenter in the early days of the development of electrostatics. He is credited with being the first to develop a way of temporarily storing static charges by using an insulated conductor. His demonstrations and experiments raised the interests of the German scientific community and the public in the development of electrical research.
Benjamin Franklin Drawing Electricity from the Sky is a c. 1805 painting by Benjamin West in the Philadelphia Museum of Art. It depicts American Founding Father Benjamin Franklin conducting his kite experiment in 1752 to ascertain the electrical nature of lighting. West composed his 13.25 in × 10 in work using oil on a slate. The painting blends elements of both Neoclassicism and Romanticism. Franklin knew West, which influenced the creation of this painting.
As for Franklin, who doubted in 1749 that the lightning was attracted by the spikes, he wrote ... the following year: 'When the electrified clouds pass over a country, the summits of mountains and trees, the high towers, the pyramids, the masts of the ships, the chimneys, etc., like so many eminences and peaks, attract the electric fire, and the whole cloud is unloaded.'