Thomas Johann Seebeck (April 9 1770 – December 10 1831) was a
physicistPhysics is a natural science; it is the study of matter and its motion through spacetime and all that derives from these, such as energy and force...
who in 1821 discovered the
thermoelectric effectThe thermoelectric effect is the direct conversion of temperature differences to electric voltage and vice versa. A thermoelectric device creates a voltage when there is a different temperature on each side. Conversely when a voltage is applied to it, it creates a temperature difference...
.
Seebeck was born in Reval (today
TallinnTallinn is the capital and largest city of Estonia. It occupies a surface of in which 405,867 inhabitants live. It is situated on the northern coast of the country, on the banks of the Gulf of Finland, south of Helsinki.-Historical names:...
,
EstoniaEstonia , officially the Republic of Estonia , is a country in Northern Europe. It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia , and to the east by the Russian Federation...
) to a wealthy Baltic German merchant family. He received a medical degree in 1802 from the University of Göttingen, but preferred to study physics. In 1821 he discovered the thermoelectric effect, where a junction of dissimilar metals produces an electric current when exposed to a temperature gradient.
Thomas Johann Seebeck (April 9 1770 – December 10 1831) was a
physicistPhysics is a natural science; it is the study of matter and its motion through spacetime and all that derives from these, such as energy and force...
who in 1821 discovered the
thermoelectric effectThe thermoelectric effect is the direct conversion of temperature differences to electric voltage and vice versa. A thermoelectric device creates a voltage when there is a different temperature on each side. Conversely when a voltage is applied to it, it creates a temperature difference...
.
Seebeck was born in Reval (today
TallinnTallinn is the capital and largest city of Estonia. It occupies a surface of in which 405,867 inhabitants live. It is situated on the northern coast of the country, on the banks of the Gulf of Finland, south of Helsinki.-Historical names:...
,
EstoniaEstonia , officially the Republic of Estonia , is a country in Northern Europe. It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia , and to the east by the Russian Federation...
) to a wealthy Baltic German merchant family. He received a medical degree in 1802 from the University of Göttingen, but preferred to study physics. In 1821 he discovered the thermoelectric effect, where a junction of dissimilar metals produces an electric current when exposed to a temperature gradient. This is now called the Peltier–Seebeck effect and is the basis of
thermocoupleA thermocouple or thermocouple thermometer is a junction between two different metals that produces a voltage related to a temperature difference. Thermocouples are a widely used type of temperature sensor for measurement and control and can also be used to convert heat into electric power...
s and
thermopileA thermopile is an electronic device that converts thermal energy into electrical energy. It is composed of thermocouples connected usually in series...
s.
Seebeck effect
In 1821 Thomas Johann Seebeck found that a circuit made from two dissimilar
metalA metal is a chemical element that is a good conductor of both electricity and heat, forms cations and ionic bonds with non-metals. In chemistry, a metal is an element, compound, or alloy characterized by high electrical conductivity. In a metal, atoms readily lose electrons to form positive ions...
s, with junctions at different temperatures would deflect a compass
magnetA magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials and attracts or repels other magnets.A permanent magnet is an object made from a...
. Seebeck initially believed this was due to
magnetismIn physics, the term magnetism is used to describe how materials respond on the microscopic level to an applied magnetic field; to categorize the magnetic phase of a material. For example, the most well known form of magnetism is ferromagnetism such that some ferromagnetic materials produce their...
induced by the temperature difference. However, it was quickly realized that it was an electrical current that is induced, which by
Ampere's lawIn classical electromagnetism, Ampère's circuital law, discovered by André-Marie Ampère in 1826, relates the integrated magnetic field around a closed loop to the electric current passing through the loop...
deflects the magnet. More specifically, the temperature difference, produces an electric potential (
voltageVoltage is commonly used as a short name for electrical potential difference. Its corresponding SI unit is the volt...
) which can drive an electric current in a closed circuit. Today, this effect is known as the Peltier–Seebeck effect.
The voltage produced is proportional to the temperature difference between the two junctions. The proportionality constant (a) is known as the Seebeck coefficient, and often referred to as the
thermoelectric powerThermoelectric power can refer to two things:# Electrical power generated from a heat source, such as burning coal, indirectly through devices like steam turbines....
or thermopower. The Seebeck voltage does not depend on the distribution of temperature along the metals between the junctions. This effect is the physical basis for a thermocouple, which is used often for temperature measurement.
The voltage difference,
V, produced across the terminals of an open circuit made from a pair of dissimilar metals, A and B, whose two junctions are held at different temperatures, is directly proportional to the difference between the hot and cold junction temperatures,
Th -
Tc.
Precursors to color photography
In 1810, at
JenaJena is a university city in central Germany on the river Saale. With a population of 103,000 it is the second largest city in the federal state of Thuringia, after Erfurt.-History:Jena was first mentioned in an 1182 document...
, Seebeck described the action of the spectrum of light on the chloride of silver. He observed that the exposed chemical would sometimes take on a pale version of the color of light that exposed it, and also reported the action of light for a considerable distance beyond the violet end of the spectrum. Seebeck also worked on the theory of color with
Johann Wolfgang von GoetheJohann Wolfgang von Goethe was a German writer and polymath. Goethe's works span the fields of poetry, drama, literature, theology, philosophy, humanism and science. Goethe's magnum opus, lauded as one of the peaks of world literature, is the two-part drama Faust...
.
Other achievements
In 1808, Seebeck was first to produce and describe the
amalgamAmalgam may refer to:* Amalgam , mercury alloy* Amalgam , material of "silver" tooth fillings* Amalgam Comics, publisher* Amalgam, Gauteng, South Africa* Amalgam , fictional character in the Marvel Universe...
of potassium. In 1810, he observed the magnetic properties of nickel and cobalt. In 1818, Seebeck discovered the optical activity of the solutions of sugar.
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