Edwin Hall
Encyclopedia
Edwin Herbert Hall was an American physicist
who discovered the "Hall effect
". Hall conducted thermoelectric research
at Harvard and also wrote numerous physics textbooks and laboratory manuals.
, U.S.
. Hall did his undergraduate work at Bowdoin College
, Brunswick, Maine
, graduating in 1875. 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.
The Hall effect was discovered by Hall in 1879, while working on his doctoral thesis (Physics). Hall's experiments 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 was appointed as Harvard's professor
of physics in 1895. Hall retired in 1921 and died in Cambridge, Massachusetts
, U.S.
in 1938.
The Hall effect is used in magnetic field sensors, present in a large number of devices.
In the presence of large magnetic field
strength and low temperature
, one can observe the quantum Hall effect, which is the quantization
of the Hall resistance. This is now the official standard for electrical resistance.
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...
who discovered the "Hall effect
Hall effect
The Hall effect is the production of a voltage difference across an electrical conductor, transverse to an electric current in the conductor and a magnetic field perpendicular to the current...
". Hall conducted thermoelectric research
Research
Research can be defined as the scientific search for knowledge, or as any systematic investigation, to establish novel facts, solve new or existing problems, prove new ideas, or develop new theories, usually using a scientific method...
at Harvard and also wrote numerous physics textbooks and laboratory manuals.
Biography
Hall was born in Gorham, MaineGorham, Maine
Gorham is a town in Cumberland County, Maine, United States. The population was 16,381 at the 2010 census. In addition to an urban village center known as Gorham Village or simply "the Village," the town also encompasses a number of smaller, unincorporated villages and hamlets with distinct...
, U.S.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. Hall did his undergraduate work at Bowdoin College
Bowdoin College
Bowdoin College , founded in 1794, is an elite private liberal arts college located in the coastal Maine town of Brunswick, Maine. As of 2011, U.S. News and World Report ranks Bowdoin 6th among liberal arts colleges in the United States. At times, it was ranked as high as 4th in the country. It is...
, Brunswick, Maine
Brunswick, Maine
Brunswick is a town in Cumberland County, Maine, United States. The population was 20,278 at the 2010 census. It is part of the Portland-South Portland-Biddeford metropolitan area. Brunswick is home to Bowdoin College, the Bowdoin College Museum of Art, the Peary-MacMillan Arctic Museum, , and the...
, graduating in 1875. He did his graduate schooling and research, and earned his Ph.D.
Doctor of Philosophy
Doctor of Philosophy, abbreviated as Ph.D., PhD, D.Phil., or DPhil , in English-speaking countries, is a postgraduate academic degree awarded by universities...
degree (1880), at the Johns Hopkins University
Johns Hopkins University
The Johns Hopkins University, commonly referred to as Johns Hopkins, JHU, or simply Hopkins, is a private research university based in Baltimore, Maryland, United States...
where his seminal experiments were performed.
The Hall effect was discovered by Hall in 1879, while working on his doctoral thesis (Physics). Hall's experiments consisted of exposing thin gold leaf
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...
(and, later, using various other materials) on a glass
Glass
Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
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
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
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
American Journal of Science
The American Journal of Science is the United States of America's longest-running scientific journal, having been published continuously since its conception in 1818 by Professor Benjamin Silliman, who edited and financed it himself...
and in the Philosophical Magazine
Philosophical Magazine
The Philosophical Magazine is one of the oldest scientific journals published in English. Initiated by Alexander Tilloch in 1798, in 1822 Richard Taylor became joint editor and it has been published continuously by Taylor & Francis ever since; it was the journal of choice for such luminaries as...
.
Hall was appointed as Harvard's professor
Professor
A professor is a scholarly teacher; the precise meaning of the term varies by country. Literally, professor derives from Latin as a "person who professes" being usually an expert in arts or sciences; a teacher of high rank...
of physics in 1895. Hall retired in 1921 and died in Cambridge, Massachusetts
Cambridge, Massachusetts
Cambridge is a city in Middlesex County, Massachusetts, United States, in the Greater Boston area. It was named in honor of the University of Cambridge in England, an important center of the Puritan theology embraced by the town's founders. Cambridge is home to two of the world's most prominent...
, U.S.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
in 1938.
The Hall effect is used in magnetic field sensors, present in a large number of devices.
In the presence of large magnetic field
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
strength and low temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
, one can observe the quantum Hall effect, which is the quantization
Quantum mechanics
Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...
of the Hall resistance. This is now the official standard for electrical resistance.
See also
- Hall effectHall effectThe Hall effect is the production of a voltage difference across an electrical conductor, transverse to an electric current in the conductor and a magnetic field perpendicular to the current...
- Henry Augustus RowlandHenry Augustus RowlandHenry Augustus Rowland was a U.S. physicist. Between 1899 and 1901 he served as the first president of the American Physical Society...
- Scientific phenomena named after peopleScientific phenomena named after peopleThis is a list of scientific phenomena and concepts named after people . For other lists of eponyms, see eponym.-A:* Abderhalden–Fauser reaction – Emil Abderhalden* Abney effect, Abney's law of additivity – William de Wiveleslie Abney...
External links and references
- Katz, Eugenii, "Hall". Biosensors & Bioelectronics.
- The President and Fellows of Harvard College, "Hall, Edwin Herbert, 1855-1938. Papers: Guide.". Houghton Library, Harvard College Library, Harvard University, Cambridge, MA. 2002.
- "Edwin Hall image". aip.org.
- Hall, Edwin, "On a New Action of the Magnet on Electric Currents". American Journal of Mathematics vol 2 1879.
Works by Hall
He 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. BergenJoseph Young BergenJoseph Young Bergen was an American botanist.-Career:Bergen was born in Red Beach, Maine. He graduated in 1872 from Antioch College, and was for a time successively a member of the Ohio Geological Survey and professor of natural sciences at Lombard College...
- Elementary Lessons in Physics (1894; 1900)
- The Teaching of Chemistry and Physics (1902), with Alexander SmithAlexander Smith (chemist)Alexander Smith was an American chemist, born in Edinburgh, Scotland. He graduated from the University of Edinburgh in 1886 and received the degree of Ph.D. at Munich in 1889. After coming to the United States, Smith was professor of chemistry and mineralogy at Wabash College and later a faculty...
- College Laboratory Manual of Physics (1904; revised edition, 1913)
- Elements of Physics (1912)