Georg Ohm
Georg Simon Ohm | |
|---|---|
 | |
| Born | March 16, 1789 |
| Died | July 6, 1854 (aged 65) |
| Nationality |  German |
| Alma mater | University of Erlangen |
| Known for | Ohm's law Ohm's phase law Ohm's acoustic law |
| Awards | Copley Medal (1841) |
| Scientific career | |
| Fields | Physics |
| Institutions | University of Munich |
| Doctoral advisor | Karl Christian von Langsdorf |
Georg Simon Ohm (March 16, 1789 - july 6 1854) was a German physicist.
As a high school teacher, Ohm started his research with the recently invented electrochemical cell, invented by Italian Count Alessandro Volta. Using equipment of his own creation, Ohm determined that the current that flows through a wire is proportional to its cross sectional area and inversely proportional to its length or Ohm's law.
Using the results of his experiments, Georg Simon Ohm was able to define the fundamental relationship among voltage, current, and resistance which represents the true beginning of electrical circuit analysis.
Biography
Early years
George Simon Ohm was born at Erlangen, Kingdom of Bavaria, to Johann Wolfgang Ohm, a locksmith and Maria Elizabeth Beck, the daughter of a tailor in Erlangen. Although his parents had not been formally educated, Ohm's father was a respected man who had educated himself to a high level and was able to give his sons an excellent education through his own teachings. Some of Ohm's brothers and sisters died in their childhood and only three survived. The survivors, including Georg Simon, were his younger brother Martin who later became a well-known mathematician, and his sister Elizabeth Barbara. His mother died when he was ten. Georg was also a very good cat breeder as a child. That was his main source of personal money
From early childhood, Georg and Martin were taught by their father who brought them to a high standard in mathematics, physics, chemistry and philosophy. Georg Simon attended Erlangen Gymnasium from age eleven to fifteen where he received little in the area of scientific training, which sharply contrasted with the inspired instruction that both Georg Simon and Martin received from their father. This characteristic made the Ohms bear a resemblance to the Bernoulli family, as noted by the professor at the University of Erlangen, Karl von Langsdorf.
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The discovery of Ohm's law
In his first paper published in 1825, Ohm examines the decrease in the electromagnetic force produced by a wire as the length of the wire increased. The paper deduced mathematical relationships based purely on the experimental evidence that Ohm had tabulated.
In two important papers in 1826, Ohm gave a mathematical description of conduction in circuits modelled on Fourier's study of heat conduction. These papers continue Ohm's deduction of results from experimental evidence and, particularly in the second, he was able to propose laws which went a long way to explaining results of others working on galvanic electricity. The second paper certainly is the first step in a comprehensive theory which Ohm was able to give in his famous book published in the following year.
What is now known as Ohm's law appeared in the famous book Die galvanische Kette, mathematisch bearbeitet (The Galvanic Circuit Investigated Mathematically) (1827) in which he gave his complete theory of electricity. The book begins with the mathematical background necessary for an understanding of the rest of the work. While his work greatly influenced the theory and applications of current electricity, it was coldly received at that time. It is interesting that Ohm presents his theory as one of contiguous action, a theory which opposed the concept of action at a distance. Ohm believed that the communication of electricity occurred between "contiguous particles" which is the term Ohm himself uses. The paper is concerned with this idea, and in particular with illustrating the differences in scientific approach between Ohm and that of Fourier and Navier[1]. A detailed study of the conceptual framework used by Ohm in formulating Ohm's law is given in [2].
Study and publications
His writings were numerous. The most important was his pamphlet published in Berlin in 1827, with the title Die galvanische Kette mathematisch bearbeitet. This work, the germ of which had appeared during the two preceding years in the journals of Schweigger and Poggendorff, has exerted an important influence on the development of the theory and applications of electric current. Ohm's name has been incorporated in the terminology of electrical science in Ohm's Law (which he first published in Die galvanische Kette...), the proportionality of current and voltage in a resistor, and adopted as the SI unit of resistance, the ohm (symbol Ω).
Although Ohm's work strongly influenced theory, at first it was received with little enthusiasm. However, his work was eventually recognized by the Royal Society with its award of the Copley Medal in 1841 [3]. He became a foreign member of the Royal Society in 1842, and in 1845 he became a full member of the Bavarian Academy.
Works
- Grundlinien zu einer zweckmäßigen Behandlung der Geometrie als höheren Bildungsmittels an vorbereitenden Lehranstalten / entworfen (Guidelines for an appropriate treatment of geometry in higher education at preparatory institutes / notes)
- Erlangen : Palm und Enke, 1817. - XXXII, 224 S., II Faltbl. : graph. Darst. (PDF, 11.2 MB)
- Die galvanische Kette : mathematisch bearbeitet (The Galvanic Circuit Investigated Mathematically)
- Berlin : Riemann, 1827. - 245 S. : graph. Darst. (PDF, 4.7 MB)
- Elemente der analytischen Geometrie im Raume am schiefwinkligen Coordinatensysteme (Elements of analytic geometry concerning the skew coordinate system)
- Nürnberg : Schrag, 1849. - XII, 590 S. - (Ohm, Georg S.: Beiträge zur Molecular-Physik ; 1) (PDF, 81 MB)
- Grundzüge der Physik als Compendium zu seinen Vorlesungen (Fundamentals of physics: Compendium of lectures)
- Nürnberg : Schrag, 1854. - X, 563 S. : Ill., graph. Darst. Erschienen: Abth. 1 (1853) - 2 (1854) (PDF, 38 MB)
References
- ^ B Pourprix, G S Ohm théoricien de l'action contigue, Arch. Internat. Hist. Sci. 45(134) (1995), 30-56
- ^ T Archibald, Tension and potential from Ohm to Kirchhoff, Centaurus 31 (2) (1988), 141-163
- ^ Winners of the Copley Medal of the Royal Society of London
See also
External links
- O'Connor, John J.; Robertson, Edmund F., "Georg Ohm", MacTutor History of Mathematics Archive, University of St Andrews
- This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). Encyclopædia Britannica (11th ed.). Cambridge University Press.
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