Michael Faraday(redirected from Faraday laws)
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Faraday, Michael(fâr`ədē, –dā'), 1791–1867, English scientist. The son of a blacksmith, he was apprenticed to a bookbinder at the age of 14. He had little formal education, but acquired a store of scientific knowledge through reading and by attending educational lectures including, in 1812, one by Sir Humphry DavyDavy, Sir Humphry,
1778–1829, English chemist and physicist. The son of a woodcarver, he received his early education at Truro and was apprenticed (1795) to a surgeon-apothecary at Penzance.
..... Click the link for more information. . The following year he became Davy's assistant at the Royal Institution in London. Faraday was made a member of the institution in 1823 and a fellow of the Royal Society in 1824. In 1825 he became director of the laboratory, and from 1833 he was Fullerian professor of chemistry at the Royal Institution. He subsequently declined knighthood and the presidency of the Royal Society.
Faraday's experiments yielded some of the most significant principles and inventions in scientific history. He developed the first dynamo (in the form of a copper disk rotated between the poles of a permanent magnet), the precursor of modern dynamos and generators. From his discovery of electromagnetic inductioninduction,
in electricity and magnetism, common name for three distinct phenomena. Electromagnetic induction is the production of an electromotive force (emf) in a conductor as a result of a changing magnetic field about the conductor and is the most important of the
..... Click the link for more information. (1831; also independently discovered by the American Joseph HenryHenry, Joseph,
1797–1878, American physicist, b. Albany, N.Y., educated at Albany Academy. He taught (1826–32) mathematics and natural philosophy at Albany Academy and was professor of natural philosophy (1832–46) at Princeton (then the College of New Jersey).
..... Click the link for more information. ) stemmed a vast development of electrical machinery for industry. In 1825 he discovered the compound benzenebenzene
, colorless, flammable, toxic liquid with a pleasant aromatic odor. It boils at 80.1°C; and solidifies at 5.5°C;. Benzene is a hydrocarbon, with formula C6H6.
..... Click the link for more information. . In addition to other contributions he did research on electrolysiselectrolysis
, passage of an electric current through a conducting solution or molten salt that is decomposed in the process. The Electrolytic Process
The electrolytic process requires that an electrolyte, an ionized solution or molten metallic salt, complete an
..... Click the link for more information. , formulating Faraday's lawFaraday's law,
physical law stating that the number of moles of substance produced at an electrode during electrolysis is directly proportional to the number of moles of electrons transferred at that electrode; the law is named for Michael Faraday, who formulated it in 1834.
..... Click the link for more information. . He also laid the foundations of the classical electromagnetic field theory, later fully developed by J. C. MaxwellMaxwell, James Clerk
, 1831–79, great Scottish physicist. After a brilliant career at Edinburgh and Cambridge, where he won early recognition with mathematical papers, he was a professor at Marischal College, Aberdeen (1856–60), and at King's College, London
..... Click the link for more information. . Some of his works were collected as Experimental Researches in Electricity (3 vol., 1839–55) and Experimental Researches in Chemistry and Physics (1859).
See his diary (ed. by T. Martin, 7 vol., 1932–36); his correspondence (ed. by L. P. Williams, 2 vol., 1971); biographies by T. Martin (1934), L. P. Williams (1965), G. Cantor (1991), and J. Hamilton (2005); studies by D. Gooding and F. A. James, ed. (1986) and N. Forbes and B. Mahon (2014).
Born Sept. 22, 1791, in London; died there Aug. 25, 1867. British physicist, chemist, and physical chemist; the founder of the science of electromagnetic fields. Fellow of the Royal Society of London (1824).
The son of a blacksmith, Faraday attended primary school. At the age of 14 he was apprenticed to a bookseller and bookbinder. Educating himself, he attended public lectures, particularly the lectures delivered by H. Davy at the Royal Institution. Davy’s lectures contributed greatly to Faraday’s decision to devote his life to science. Faraday asked Davy for a position at the Royal Institution, and his request was granted in 1813. From 1813 to 1815, he traveled with Davy in Europe, visiting laboratories in France and Italy. Faraday’s later scientific work was conducted at the Royal Institution, where he initially assisted Davy in chemical experiments and then began independent chemical investigations. His most important independent studies were the isolation of benzene in 1825 and the liquefaction of chlorine and certain other gases in 1823. Faraday’s name became famous in scientific circles; he was appointed director of the Royal Institution’s laboratory in 1825 and became a professor at the institution in 1827.
Faraday was a talented experimenter endowed with scientific intuition. He conducted a number of experiments in which fundamental physical laws and phenomena were discovered. Having learned of H. Oersted’s work in 1820 on the deflection of a magnetic needle near a current-carrying wire, Faraday investigated the relationship between electrical and magnetic phenomena. In 1821 he discovered for the first time the rotation of a magnet around a current-carrying wire and the rotation of a current-carrying wire around a magnet. During the next ten years, Faraday attempted to “convert magnetism into electricity.” His investigations culminated in 1831 with the discovery of electromagnetic induction. He studied electromagnetic induction in detail and derived its fundamental law and explained the dependence of the induced current on the magnetic properties of the medium. He also investigated self-induction and the extra currents induced by the making or breaking of an electric circuit. The discovery of electromagnetic induction immediately attained enormous scientific and practical importance, becoming the basis of electrical engineering.
Faraday proposed novel ideas, which were later confirmed, about, for example, the nature of currents and magnetism and the mechanism of electrical conduction in various media. He proved that different kinds of electricity are identical, including frictional, “animal,” and magnetic electricity. In an attempt to establish quantitative relationships between the different kinds of electricity, Faraday investigated electrolysis, discovering the laws of electrolysis in 1833 and 1834 (seeFARADAVS LAWS OF ELECTROLYSIS). He introduced a terminology for electrolysis that is still in use today. The laws of electrolysis were a strong argument for the discrete nature of matter and electricity. In 1840, before the law of conservation of energy was discovered, Faraday proposed the concept of the unity of the “forces” of nature—that is, different kinds of energy—and their conversion into each other. He introduced the concept of lines of force, which he considered physically real. Faraday’s ideas about electric and magnetic fields had a great effect on all areas of physics. In 1832, Faraday suggested that the propagation of electromagnetic radiation is a wave process that occurs at a finite speed.
In 1845, while investigating the magnetic properties of various materials, Faraday discovered paramagnetism and diamagnetism. In 1845 he also discovered the rotation of the plane of polarization of light in a magnetic field; this phenomenon is called the Faraday effect. This discovery was the first observation of the relationship between magnetic and optical phenomena that later corroborated J. Maxwell’s electromagnetic theory of light. In an attempt to explain the nature of electricity, Faraday also studied electrical discharges in gases.
Faraday’s discoveries earned recognition throughout the scientific world. Maxwell was the first to “translate” Faraday’s ideas into conventional mathematical language. In the preface to his Treatise on Electricity and Magnetism (1873), Maxwell wrote, “As I proceeded with the study of Faraday, I perceived that his method of conceiving the phenomena was also a mathematical one, though not exhibited in the conventional form of mathematical symbols” (Izbr. trudy po teorii elektromagnitnogo polia, Moscow, 1954, p. 349). Various laws, phenomena, physical units, and devices were later named after Faraday; these include the farad, the faraday, the Faraday constant, and the Faraday cylinder.
F. Engels regarded Faraday as the greatest researcher in the field of electricity. Commenting on Faraday’s importance in the development of science, A. G. Stoletov wrote: “Never since the time of Galileo has the world seen so many remarkable and diverse discoveries issuing from a single mind” (Sobr. soch., vol. 2, 1941, p. 145).
WORKSExperimental Researches in Chemistry and Phuysics. London, 1859.
Faraday’s Diary ..., vols. 1–7. London, 1932–36.
In Russian translation:
Eksperimental’nye issledovaniia po elektrichestvu, vols. 1–3. Moscow 1947–59. (Contains a bibliography.)
REFERENCERadovskii, M. I. Mikhail Faradei: Biograficheskii ocherk. Moscow-Leningrad, 1946.
IA. M. GELFER