Michael Faraday (22.09.1791-25.08.1867) — English physicist, a Fellow of the Royal Society (1824). Born in London. Self-taught. In 1813 he became an assistant to H. Davy at the Royal Institution in London, in 1825 director of the laboratory of the Royal Institution, succeeding H. Davy in that post, and in 1833 —62 professor of chemistry.
His research was in the fields of electricity, magnetism, magneto-optics and electrochemistry. In 1821 he was the first to make a magnet rotate around a current-carrying conductor and a current-carrying conductor around a magnet, thereby creating a laboratory model of the electric motor. This experiment showed clearly the connection between electric and magnetic phenomena. It is no accident that in the same year Faraday set himself the aim of “converting magnetism into electricity”. In 1831 he discovered the phenomenon of electromagnetic induction — the appearance of an electric current in a conductor when the magnetic flux through the circuit of the conductor changes. In the following years he studied the phenomenon he had discovered in detail and established the laws of electromagnetic induction, and discovered (1835) the extra currents on closing and opening a circuit and established their direction.
Using an enormous body of experimental material, Faraday proved the identity of the kinds of electricity then known: “animal”, “magnetic”, thermoelectricity, electricity produced by friction, and galvanic electricity. His wish to clarify the nature of the electric current led him to experiments on the passage of current through solutions of acids, salts and alkalis. The result of these studies was the discovery in 1833 of the laws of electrolysis (Faraday's laws). Besides their great practical importance, these laws became an essential argument for the discrete nature of electricity. He introduced the concepts of mobility (1827), cathode, anode, ions, electrolysis, electrolytes and electrodes (1834), and invented (1833) the voltameter. In 1845 he discovered diamagnetism and in 1847 paramagnetism. He detected (1845) the rotation of the plane of polarisation of light in a magnetic field (the Faraday effect). The latter was the first experimental proof of a connection between light and magnetism and began magneto-optics.
In Faraday's work on electromagnetism the concept of the field is also important. He was the first, in the 1830s, to introduce the concept of the field, in 1845 he used the term “magnetic field”, and in 1852 he formulated his concept of the field clearly. In the opinion of A. Einstein, the idea of the field was Faraday's most original idea, the most important discovery since Newton. For Newton and other scientists space appeared as a passive container of bodies and electric charges, whereas for Faraday space takes part in the phenomena. “One needs a powerful gift of scientific foresight, — wrote A. Einstein, — to recognise that in describing electrical phenomena it is not the charges and the particles that describe the essence of the phenomena, but rather the space between the charges and the particles.” To describe electric and magnetic phenomena Faraday introduced the notion of electric and magnetic lines of force, which he, however, considered to exist in reality. He was the creator of the doctrine of the electromagnetic field. In 1846, in his memoir “Thoughts on Ray-Vibrations”, he put forward the idea of the electromagnetic nature of light.
In 1837 he detected the influence of dielectrics on electric interaction (the polarisation of dielectrics) and introduced the concept of permittivity. He expressed the idea that electric and magnetic interactions propagate through an intermediate medium. In 1843 he proved experimentally the law of conservation of electric charge. He came close to discovering the law of conservation and transformation of energy, having expressed (1840) the idea of the unity of the forces of nature (the different kinds of energy) and their mutual transformation.
He was a popularizer of physics, and in particular his book “The Chemical History of a Candle”, translated into almost all the languages of the world, is widely known.
Member of the St Petersburg Academy of Sciences (1830).