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'''André-Marie Ampère''' (Lyons 20 January, 1775 – Marseilles 10 June, 1836) was a French physicist and mathematician. His most important contribution was [[Ampere's law]], which describes the relation between electric current and magnetic field. The unit of electric current [[Ampere (unit)|ampere]] is named after him. | '''André-Marie Ampère''' (Lyons 20 January, 1775 – Marseilles 10 June, 1836) was a French physicist and mathematician. His most important contribution was [[Ampere's law]], which describes the relation between electric current and magnetic field. The unit of electric current [[Ampere (unit)|ampere]] is named after him. | ||
==References== | |||
Paul Jonathan Bruce, ''The History of Electromagnetic Theory'', Ph.D. Thesis, University of Aberdeen, 2005. | |||
'''(To be continued)''' | '''(To be continued)''' | ||
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André-Marie Ampère | |||
André-Marie Ampère (1775-1836) was born near Lyon, France where he received no formal schooling; instead, his father inspired and taught him in the languages and the sciences. He was appointed the position of Professor of Physics and Chemistry at the Central Learning School in Bourg and later a chair at the Universite de France, Paris. | |||
Ampère was not known to be a methodical experimenter; he was subject to brilliant flashes of inspiration, which he would then pursue to their conclusion; during the week following Øersted’s discovery one such flash occurred. On 18 September 1820, exactly one week after the news of Øersted’s first discovery had arrived, Ampère attended a meeting at the Academy of Sciences and presented the Academy with the first of five papers of which he would write on the subject. He showed that two parallel wires carrying currents attract each other if the currents are in the same direction, and repel each other if the currents are in the opposite direction. The force between the two current carrying wires was inversely proportional to the distance separating them and proportional to the magnitude of current flowing through them; thus, Ampère had given birth to electrodynamics. During the following years he continued his researches, publishing in 1825 his collected results in one of the most celebrated memoirs in the history of natural philosophy – Memoir on the Mathematical Theory of Electrodynamic Phenomena, Uniquely Deduced from Experience. | |||
He formulated a law of electromagnetism, commonly known as Ampère’s law that mathematically describes the magnetic force between two electric currents. He pursued many experimental results, of which served to develop further mathematical theory that not only explained electromagnetic phenomena already reported but predicted new ones also. | |||
Ampère was the first person to develop a technique for measuring electricity; he built an instrument utilising a free-moving needle to measure the flow of electricity, its later refinement being known as the galvanometer. Ampère used a highly sensitive galvanometer to make many of his experimental measurements. A galvanometer is simply a device used to detect and measure the flow of electricity; it is composed of a | |||
compass with a wire wrapped around it. When either end of the wire is connected to whatever you want to test, such as a battery; the needle is deflected because a current has been created; the stronger the current the greater the deflection of the needle. | |||
Ampère’s theories became fundamental for 19th century developments in electricity and magnetism. James Clerk Maxwell, whom we shall talk of later, in his memoirs, writes of Ampère: “We can scarcely believe that Ampère really discovered the law of action by means of the experiments which he describes. We are led to suspect, what, indeed, he tells us himself, that he discovered the law by some process which he has not shown us, and that when he had afterwards built up a perfect demonstration he removed all traces of the scaffolding by which he had raised it.” | |||
André-Marie Ampère died on June 10, 1836, in Marseille, France, in his fifty-second year and was buried in Cimetiere de Montmartre, Paris. | |||
1802 Professor für Physik in Bourg-en-Bresse | |||
1804 Professor für Mathematik an der Ècole Polytechnique | |||
1808 Generalinspekteur der Universität Paris | |||
1824 Professor für Physik am Collège de France in Paris | |||
Despite his celebrated accomplishments, Ampère led a rather tragic life. When Lyons was taken over by rebels during the French Revolution, his beloved father was a district judge. Because of his political affiliations, Ampère’s father was taken as a political prisoner and then publicly executed by guillotine, an event that severely scarred the young Ampère and led to a period of psychological depression. Later in life Ampère’s first wife met with an early death after a prolonged illness, and although he remarried, his second marriage was unhappy and unsuccessful. | |||
GÉOMÉTRIE – Sur la rectification d'un arc quelconque de cercle plus petit que la demi-circonférence, | |||
par André-Marie Ampère, âgé de treize ans (8 juillet 1788). | |||
MÉMOIRE | |||
Présenté à l'Académie royale des Sciences, le 2 octobre 1820, où se trouve compris le résumé de ce | |||
qui avait été lu à la même Académie les 18 et 25 septembre 1820, sur les effets des courans | |||
électriques. | |||
PAR M. AMPÈRE. | |||
§1er. De l'Action mutuelle de deux courans électriques. | |||
§ III. De l'Action mutuelle entre un conducteur électrique et un aimant (magnet). | |||
C'est cette action découverte par M. OErsted, qui m'a conduit à reconnaître celle de deux courans | |||
électriques l'un sur l'autre, celle du globe terrestre sur un courant, et la manière dont | |||
l'électricité produisait tous les phénomènes que présentent les aimans, par une distribution | |||
semblable à celle qui a lieu dans le conducteur d'un courant électrique, suivant des courbes fermées | |||
perpendiculaires à l'axe de chaque aimant. Ces vues, dont la plus grande partie n'a été que plus | |||
tard confirmée par l'expérience, furent communiquées à l'Académie royale des Sciences, dans sa | |||
séance du 18 septembre 1820 ; | |||
AMPERE, André-Marie. Mémoire présenté à l'Académie royale des Sciences, le 2 octobre 1820, où se trouve compris le résumé de ce qui avait été lu à la même Académie les 18 et 25 septembre 1820, sur les effets des courans électriques. Annales de chimie et de physique, 1820, vol. 15, p. 59-74, p.170-218 | |||
Chimie | |||
Lettre de M. Ampère à M. le comte Berthollet sur la détermination des proportions dans lesquelles les corps se combinent d'après le nombre et la disposition respective des molécules dont les parties intégrantes sont composées, Annales de chimie, 1814, (vol. 90, n°1), p. 43-86. | |||
Mathématiques | |||
Considérations générales sur les intégrales des équations aux différences partielles, Journal de l'Ecole Polytechnique, 1815, (vol. 10, n°17), p. 549-611. | |||
Electricité | |||
Mémoire sur l'action mutuelle entre deux courants électriques, un courant électrique et un aimant ou le globe terrestre, et entre deux aimants, Annales de chimie et de physique, 1820, (vol. 15), p. 59-75, p. 170-218. | |||
Mémoire sur la théorie mathématique des phénomènes électrodynamiques uniquement déduite de l'expérience, in Mémoires de l'Académie Royale des Sciences, année 1823, tome VI, 1827, p. 175-388. | |||
“Memoir on the Mathematical Theory of Electrodynamic Phenomena, Uniquely Deduced from Experience” (work by Ampere) | |||
Ampère was present at the Académie des Sciences on Sept. 11, 1820, when François Arago performed - for the first time in France - Hans Christian Oersted’s experiment demonstrating the magnetic effects of current-carrying wires on magnetized needles. Inspired by Oersted’s discovery, Ampère immediately concluded that magnetism was electricity in motion, an intuitive leap which he sought to confirm by experiment. | |||
During September and October 1820, Ampère per-formed a series of experiments designed to elucidate the exact nature of the relationship between electric current-flow and magnetism, as well as the relationships governing the behavior of electric currents in various types of conductors. His investigations, reported weekly before the Académie des Sciences, established the new science of electrodynamics. | |||
Mémoire présenté à l’Académie royale des sciences | |||
Annales de Chimie tome XV | |||
André-Marie Ampère | |||
1820 | |||
Ampère’s most detailed report on the events of September and October 1820 was published as a lengthy two-part memoir in the Annales de Chimie et de Physique. Written hurriedly and in disjointed segments, it is a rich source of information in spite of its chronological errors. . . .” (Hofmann, p. 238). Among the discoveries described in this memoir are Ampère’s demonstration of the tangential orientation of a magnetic needle by an electric current when terrestrial magnetism is neutralized; his proof that conducting planar spirals attract and repel each other and respond to bar magnets in an analogy to magnetic poles; and his demonstration of electrodynamic forces between linear conducting wires. The memoir’s plates illustrate the several instruments that Ampère devised to carry out his experiments (see below). | |||
Ampère Table | |||
1890 | |||
Ampère’s scientific genius, while capable of remarkable leaps of insight, was somewhat lacking in organization and discipline. It often happened that Ampère would publish a paper one week, only to find the following week that he had thought of several new ideas that he felt ought to be incorporated into the paper. Since he could not alter the original, he would add his revisions to the separately published reprints of the paper, and even modify the revised versions later if he felt it necessary; some of his papers exist in as many as five different versions. | |||
A separate reprint of Ampère’s Mémoire was issued in 1821; however, it differs substantially from the journal publication, which must be considered the original version of this foundation document in electrodynamics. | |||
DSB. Hofmann, Andre-Marie Ampère, ch. 7 (containing a detailed account of Ampère’s investigations). Norman 43 (1821 reprint). 37292 | |||
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Revision as of 08:32, 12 February 2008
André-Marie Ampère (Lyons 20 January, 1775 – Marseilles 10 June, 1836) was a French physicist and mathematician. His most important contribution was Ampere's law, which describes the relation between electric current and magnetic field. The unit of electric current ampere is named after him.
References
Paul Jonathan Bruce, The History of Electromagnetic Theory, Ph.D. Thesis, University of Aberdeen, 2005.
(To be continued)