Edwin Hall (trade Unionist)

Edwin Herbert Hall (November 7, 1855 – November 20, 1938) was an American physicist who discovered the electric field Hall effect. Hall also conducted thermoelectric research and wrote numerous physics textbooks and laboratory manuals.

Biography

Education

Born in Gorham, Maine, Hall did his undergraduate work at Bowdoin College, Brunswick, Maine, graduating in 1875. He was the Principal of Gould Academy (1875–1876) and the Principal of Brunswick High School (1876–1877). He did his graduate schooling and research, and earned his Ph.D. degree (1880), at the Johns Hopkins University where his seminal experiments were performed.

Career

Hall was appointed as a professor of physics at Harvard University in 1895, and succeeded John Trowbridge to the Rumford Chair of Physics in 1914. During the 1919 Boston police strike, Hall briefly volunteered as a strikebreaking police officer. After returning to the physics department, Hall retired in 1921 and died in Cambridge, Massachusetts, in 1938.

Discovery of the Hall effect

The Hall effect was discovered by Hall in 1879, while working on his doctoral thesis in Physics under the supervision of Henry Augustus Rowland. Hall's experiments in electromagnetics consisted of exposing thin gold leaf (and, later, using various other materials) on a glass plate and tapping off the gold leaf at points down its length. The effect is a potential difference (''Hall voltage'') on opposite sides of a thin sheet of conducting or semiconducting material (the ''Hall element'') through which an electric current is flowing. This was created by a magnetic field applied perpendicular to the ''Hall element''. The ratio of the voltage created to the amount of current is known as the ''Hall resistance'', and is a characteristic of the material in the element. In 1880, Hall's experimentation was published as a doctoral thesis in the American Journal of Science and in the Philosophical Magazine.

Hall effect sensors use his ''Hall effect'' to detect the magnetic field. Hundreds of millions are sold every year and are present in a large number of devices, including high efficiency electric propulsion systems on spacecraft.

In the presence of large magnetic field strength and low temperature, one can observe the quantum Hall effect, the quantization of the Hall resistance and in 1990 became a calibration standard for electrical resistance due to its low uncertainty (see ).

Works

Hall made various contributions to scientific journals on the thermal conductivity of iron and nickel, the theory of thermoelectric action, and on thermoelectric heterogeneity in metals. His publications include:

''A Text-Book of Physics''
(1891; third edition, 1903), with J. Y. Bergen

''Elementary Lessons in Physics''
(1894; 1900)
* ''The Teaching of Chemistry and Physics'' (1902), with Alexander Smith
* ''College Laboratory Manual of Physics'' (1904; revised edition, 1913)
* ''Elements of Physics'' (1912)

See also

* Hall effect
* Henry Augustus Rowland
* Scientific phenomena named after people

Relevant lists

* List of eponyms
* List of physicists

References

External links

* Katz, Eugenii,
Hall
. Biosensors & Bioelectronics.
* The President and Fellows of Harvard College,

. Houghton Library, Harvard College Library, Harvard University, Cambridge, MA. 2002.
*
Edwin Hall image
. aip.org.
* Hall, Edwin,

. ''American Journal of Mathematics'' vol. 2 pp. 287–292, 1879.
*

{{DEFAULTSORT:Hall, Edwin
1855 births
1938 deaths
American physicists
Hall effect
People from Gorham, Maine
Bowdoin College alumni
Johns Hopkins University alumni
Harvard University faculty
Burials at Mount Auburn Cemetery