James Wattson

Georg Simon Ohm 

Born :     16 March 1789 Erlangen, Brandenburg-Bayreuth

Died :      6 July 1854 Munich, Kingdom of Bavaria

Nationality :   German

Fields :     Physics

Known for :      Ohm's law

                          Ohm's Phase law

                          Ohm's acoustic law

Notable awards :    Copley Medal (1841)

Georg Simon Ohm (16 March 1789 – 6 July 1854) was a German physicist and mathematician. As a school teacher, Ohm began his research with the new electrochemical cell, invented by Italian scientist Alessandro Volta. Using equipment of his own creation, Ohm found that there is a direct proportionality between the potential difference (voltage) applied across a conductor and the resultant electric current. This relationship is known as Ohm's law.

Early years

Georg Simon Ohm was born into a Protestant family in Erlangen, Brandenburg-Bayreuth (then a part of the Holy Roman Empire), son 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. Of the seven children of the family only three survived to adulthood: Georg Simon, his younger brother Martin, who later became a well-known mathematician, and his sister Elizabeth Barbara. His mother died when he was ten.

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 and Martin received from their father. This characteristic made the Ohms bear a resemblance to the Bernoulli family, as noted by Karl Christian von Langsdorf, a professor at the University of Erlangen.

Teaching career

Ohm's own studies prepared him for his doctorate which he received from the University of Erlangen on October 25, 1811. He immediately joined the faculty there as a lecturer in mathematics but left after three semesters because of unpromising prospects. He could not survive on his salary as a lecturer. The Bavarian government offered him a post as a teacher of mathematics and physics at a poor quality school in Bamberg which Ohm accepted in January 1813. Unhappy with his job, Georg began writing an elementary textbook on geometry as a way to prove his abilities. Ohm's school was closed down in February 1816. The Bavarian government then sent him to an overcrowded school in Bamberg to help out with the teaching of mathematics.

The discovery of Ohm’s law

Ohm's law first appeared in the famous book Die galvanische Kette, mathematisch bearbeitet (tr., The Galvanic Circuit Investigated Mathematically) (1827) in which he gave his complete theory of electricity.  In this work, he stated his law for electromotive force acting between the extremities of any part of a circuit is the product of the strength of the current, and the resistance of that part of the circuit.

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 he himself used. The paper is concerned with this idea, and in particular with illustrating the differences in this scientific approach of Ohm's and the approaches of Joseph Fourier and Claude-Louis Navier.

A detailed study of the conceptual framework used by Ohm in producing Ohm's law has been presented by Archibald. The work of Ohm marked the early beginning of the subject of circuit theory, although this did not become an important field until the end of the century.

Ohm’s acoustic law

Ohm's acoustic law, sometimes called the acoustic phase law or simply Ohm's law, states that a musical sound is perceived by the ear as a set of a number of constituent pure harmonic tones. It is well known to be not quite true.