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
Georg 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.
Life in university
In 1805, at age 15, Ohm entered the University of
Erlangen. Rather than concentrate on his studies he spent much time dancing, ice skating and playing billiards. Ohm's
father, angry that his son was wasting the educational opportunity, sent Ohm to Switzerland where, in September 1806, he took up
a post as a mathematics teacher in a school in Gottstadt bei Nydau.
Karl Christian von
Langsdorf left the University of Erlangen in early 1809 to take up a post in the
University of Heidelberg and Ohm would have liked to have gone
with him to Heidelberg to restart his mathematical studies. Langsdorf, however, advised Ohm
to continue with his studies of mathematics on his own, advising Ohm to read the works of Euler, Laplace and Lacroix. Rather reluctantly Ohm took his advice but he left his teaching post in Gottstadt
bei Nydau in March 1809 to become a private tutor in Neuchâtel. For two years he carried out
his duties as a tutor while he followed Langsdorf's advice and continued his private study of mathematics. Then in April 1811 he
returned to the University of Erlangen.
Teaching career
His studies had stood him in good stead for his receiving a doctorate from Erlangen on
October 25, 1811 and immediately joined the staff as a
mathematics lecturer. After three semesters Ohm gave up his university post because of unpromising prospects while he couldn't
make both ends meet with the lecturing post. The Bavarian government offered him a post as a teacher of mathematics and physics
at a poor quality school in Bamberg and he took up the post there in January
1813. Feeling unhappy with his job, Georg devoted to writing an elementary book on Geometry as a way to prove his true ability. The school was then closed down in February 1816. The Bavarian government sent him to an overcrowded school in Bamberg to help out with the mathematics
teaching.
After that, he sent the manuscript to King Wilhelm III of Prussia
upon its completion. The King satisfied with Georg's work and he offered Ohm a position at a Jesuit Gymnasium of Cologne on September 11 1817. Thanks to the
school's reputation for science education, Ohm found himself required to teach physics as well as mathematics. Luckily, the
physics lab was well-equipped, so Ohm devoted himself to experimenting on physics. Being the son of a locksmith, Georg had some
practical experience with mechanical equipment.
He became in the polytechnic school of Nuremberg in 1833, and
in 1852 became professor of experimental physics in the university of Munich, where he later died.
The discovery of Ohm's law
- Further information: Ohm's Law
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
See also
External links
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