Michael Faraday

Michael Faraday (, – , ) was a (a and ) who contributed significantly to the fields of and . He also invented the earliest form of the device that was to become the , which is used almost universally in science laboratories as a convenient source of heat.
Michael Faraday was one of the great scientists in history. Some historians of science refer to him as the greatest experimentalist in the history of science. It was largely due to his efforts that became viable for use in technology. The unit of , the (symbol F) is named after him.
Early career
Michael Faraday was born in , near present-day , . His family was poor (his father, James Faraday, was a blacksmith) and he had to educate himself. At fourteen he became apprenticed to bookbinder and seller and, during his seven year apprenticeship, read many books, developing an interest in science and specifically electricity.
At the age of twenty Faraday attended lectures by the eminent scientist Sir , president of the , and , founder of the . After Faraday sent Davy a sample of notes taken during the lectures, Davy said he would keep Faraday in mind but should stick to his current job of book-binding. After Davy damaged his eyesight in an accident with , also known as trichloramine, he employed Faraday as a secretary. When John Payne of the was fired, Davy recommended Faraday for the job of laboratory assistant. Faraday eagerly left his bookbinding job as his new employer, , was hot-tempered.
In a class-based society, Faraday was not considered a gentleman; it has been said that Davy's wife, , refused to treat him as an equal and, when on a continental tour, made Faraday sit with the servants. However, it was not long before Faraday surpassed Davy.
He also was the first to link electricity to magnetism and then link magnetism back to electricity - i.e. he induced an electric current using magnets - thus inventing the dynamo, predecessor to today's .
Scientific career
His greatest work was with electricity. In , soon after the Danish chemist, discovered the phenomenon of , Davy and tried but failed to design an . Faraday, having discussed the problem with the two men, went on to build two devices to produce what he called electromagnetic rotation: a continuous circular motion from the circular magnetic force around a wire. A wire extending into a pool of with a magnet placed inside would rotate around the magnet if charged with electricity by a chemical battery. This device is known as a . These experiments and inventions form the foundation of modern electromagnetic technology. Unwisely, Faraday published his results without acknowledging his debt to Wollaston and Davy, and the resulting controversy caused Faraday to withdraw from electromagnetic research for several years.
Ten years later, in , he began his great series of experiments in which he discovered , though the discovery may have been anticipated by the work of . He found that if he moved a magnet through a loop of wire, an electric current flowed in the wire. The current also flowed if the loop was moved over a stationary magnet.
His demonstrations established that a changing magnetic field produces an electric field. This relation was mathematically modelled by , which subsequently became one of the four . These in turn evolved into the generalization known as field theory.
Faraday then used the principle to construct the electric , the ancestor of modern power generators.
Faraday proposed that electromagnetic forces extended into the empty space around the conductor, but did not complete his work involving that proposal. Faraday's concept of lines of flux emanating from charged bodies and magnets provided a way to visualize electric and magnetic fields. That mental model was crucial to the successful development of electromechanical devices which dominated engineering and industry for the remainder of the 19th century.
Faraday also dabbled in , discovering chemical substances such as , inventing the system of numbers, and liquefying gases such as . He also discovered the laws of and popularized terminology such as , , , and .
In he discovered what is now called the and the phenomenon that he named . The plane of of linearly polarized light propagated through a material medium can be rotated by the application of an external magnetic field aligned in the propagation direction. He wrote in his notebook, "I have at last succeeded in illuminating a magnetic curve or line of force and in magnetising a ray of light". This established that magnetic force and light were related.
In his work on static electricity, Faraday demonstrated that the charge only resided on the exterior of a charged conductor, and exterior charge had no influence on anything enclosed within a conductor. This is because the exterior charges redistribute such that the interior fields due to them cancel. This shielding effect is used in what is now known as a .
Miscellaneous
He gave a successful series of lectures on the chemistry and physics of flames at the , entitled ; this was the origin of the for young people that are still given there every year and bear his name.
Faraday was known for designing ingenious experiments, but lacked a good education. (However, his affiliation with helped in this regard, as Maxwell was able to translate Faraday's experiments into mathematical language.) He was regarded as handsome and modest, declining a knighthood and presidency of the Royal Society (Davy's old position).
Michael Faraday on a British Ј20 banknote.
His picture has been printed on British Ј20 .
His sponsor and mentor was , who created the Fullerian Professorship of Chemistry at the Royal Institution. Faraday was the first, and most famous, holder of this position to which he was appointed for life.
Faraday was also devoutly religious and a member of the small denomination, an offshoot of the . He served two terms as an elder in the group's church.
Faraday married Sarah Barnard in but they had no children. They met through attending the Sandemanian church.
He died at his house at Hampton Court on , .

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