History of Magnetism
Date | Event |
---|---|
900 a.C. | Magnes, a Hellenic shepherd, walked across a field of black stones (loadstone Fe3O4) and recognized that these stones attracted the iron nails of his sandals. |
cannot be dated exactly: | Vikings and Chinese used the compass. |
1269 | Petrus Peregrinus (Italy) found out that loadstone arranges iron needles along lines of longitude between the poles. |
1600 | William Gilbert, court physician of Queen Elizabeth, discovered the analogy of the geomagnetic field to the stones of Peregrinus. Explanation how the compass works. |
1742 | Thomas Le Seur and Francis Jacquier discovered that the force between two magnets is proportional to 1/r3. |
1750 | John Michell discovers that both poles of a magnet have the same strength. |
1820 | Hans Christian Oersted found out that electric current, flowing through a conductor, aligns compass needles vertical to the conductor. |
1820 | One week after he had heard of Oersteds discovery, André Marie Ampère showed that conductors flowed through by electric current exert force on each other. |
1820 | Jean-Baptiste Biot and Felix Savart showed that forces, which are exerted on an magnet by a conductor that is flowed through by electric current, drop with a rate of 1/r (later: Biot-Savart's law). |
1825 | Ampère published the extensive results of his research on magnetism. |
1831 | Michael Faraday showed that alternating currents in a circuit also induce currents in a neighboring circuit. Introduction of the "Magnetic flow". |
1834 | Faraday discovered the self-induction. Emil Lenz defined his law of definition of the direction of induced currents (Lenz's rule). |
1838 | Faraday ascertained the analogy of induced electricity in isolators and induced magnetism in magnetic materials. |
1845 | Faraday ceased his four years of rest and discovered that the polarity level of light rotates if it runs in glass along flux lines of an electromagnet (Faraday rotation). |
1846 | Faraday published the presumption that light is of electromagnetic origin. He discovered diamagnetism, for example in glass, bismuth and other materials. |
1847 | Weber proposed that diamond magnetism arises from Faraday induction of molecular currents. Diamagnetism is omnipresent and is merely overlapped in para- and ferromagnets. |
1850 | William Thomson (Lord Kelvin) introduced the magnetic permeability and susceptibility |
1864 | Maxwell completed his comprehensive characterization of electricity and magnetism (Maxwell Equations). |
1879 | Edwin Hall discovered the Hall effect. |
1896 | P. Zeeman discovered the splitting of line spectrum caused by magnetic fields (Zeeman effect). |
20th Century | Theory of relativity, quantum mechanics, nuclear physics, solid state physics, material sciences ... |
URL of this article
https://www.hzdr.de/db/Cms?pOid=33057