|
|
| (One intermediate revision by one other user not shown) |
| Line 1: |
Line 1: |
| {{Infobox scientist
| | Alyson Meagher is the title her parents gave her but she doesn't like when people use her full title. Mississippi is exactly where her house is but her husband wants them to move. Credit authorising is how he makes cash. To perform lacross is 1 of the issues she loves most.<br><br>Also visit my blog post; good psychic ([http://drive.ilovetheory.com/content/hobbies-confusing-you-short-article-will-clear-it-yourself http://drive.ilovetheory.com/]) |
| | name = Thomas Johann Seebeck
| |
| | image = ThomasSeebeck.jpg|thumb|225px
| |
| | image_size =
| |
| | caption =
| |
| | birth_date = {{birth-date|9 April 1770|9 April 1770}}
| |
| | birth_place = [[Reval]]
| |
| | death_date = {{death-date|10 December 1831|10 December 1831}}
| |
| | death_place = Berlin<ref>{{cite book | title = A Scientific German Reader | author = George Theodore Dippold | publisher = Ginn & Co. | year = 1904 | url = http://books.google.com/books?id=_2kBAAAAYAAJ&pg=PA216&dq=%22Thomas+Johann+Seebeck%22#PPA212,M1 }}</ref>
| |
| | residence =
| |
| | citizenship =
| |
| | nationality =
| |
| | ethnicity = [[Baltic German]]
| |
| | field = [[Physics]]
| |
| | work_institutions =
| |
| | alma_mater =
| |
| | doctoral_advisor =
| |
| | doctoral_students =
| |
| | known_for = Discovering the [[thermoelectric effect]]
| |
| | author_abbrev_bot =
| |
| | author_abbrev_zoo =
| |
| | prizes =
| |
| | religion =
| |
| | footnotes =
| |
| }}
| |
| '''Thomas Johann Seebeck''' (pronounced {{IPA-de|ˈtoːmas ˈjoːhan ˈzeːbɛk|}}; 9 April 1770 – 10 December 1831) was a [[physics|physicist]] who in 1821 discovered the [[thermoelectric effect]].
| |
| | |
| Seebeck was born in Reval (today [[Tallinn]], [[Estonia]]) to a wealthy [[Baltic Germans|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 [[thermocouple]]s and [[thermopile]]s.
| |
| | |
| ==Seebeck effect==
| |
| | |
| [[File:Thomas Johann Seebeck.jpg|thumb|upright|A plaque in honor of Seebeck in Tallinn, Estonia]]
| |
| | |
| In 1821 Thomas Johann Seebeck found that a circuit made from two dissimilar [[metal]]s, with junctions at different temperatures would deflect a compass [[magnet]]. Seebeck initially believed this was due to [[magnetism]] induced by the temperature difference. However, it was quickly realized that it was an electrical current that is induced, which by [[Ampere's law]] deflects the magnet. More specifically, the temperature difference, produces an electric potential ([[voltage]]) 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 power 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.
| |
| | |
| <math>V = a(T_h - T_c)\,\!</math> | |
| | |
| 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, ''T''<sub>h</sub> − ''T''<sub>c</sub>.
| |
| The voltage or current produced across the junctions of two different metals is caused due to the diffusion of electrons from high electron density region to low electron density region as the density of electrons is different in different metals. Due to this the current flows in opposite direction.
| |
| If both the junctions are kept at same temperature,equal amount of electron diffuses at both the junctions. Therefore the current at both the junctions are equal and opposite and the net current is zero, and if both the junctions are kept at different temperature then diffusion at both the junctions are different and hence different amount of current is produced. Therefore the net current is not zero. This is known as the phenomena of thermoelectricity.
| |
| | |
| ==Precursors to color photography==
| |
| | |
| In 1810, at [[Jena]], 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.<ref>{{cite book | title = The Encyclopædia Britannica: A Dictionary of Arts, Sciences, Literature and General Information | author = Hugh Chisholm, editor | year = 1911 | edition = Eleventh ed. | volume = XXI | pages = 485 | url = http://books.google.com/books?id=hGgEAAAAYAAJ&pg=PA485&dq=%22Thomas+Johann+Seebeck%22}}</ref> Seebeck also worked on the ''[[Theory of Colours]]'' with [[Johann Wolfgang von Goethe|Goethe]].
| |
| | |
| ==Other achievements==
| |
| In 1808, Seebeck was first to produce and describe the [[amalgam (chemistry)|amalgam]] 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.
| |
| | |
| ==See also==
| |
| * [[List_of_Baltic_Germans#Scientists|List of Baltic German scientists]]
| |
| | |
| ==References==
| |
| {{Reflist}}
| |
| | |
| ==Further reading==
| |
| * {{DSB
| |
| |first= Eugene
| |
| |last= Frankel
| |
| |title= Seebeck, Thomas
| |
| |volume= 12
| |
| |pages= 281-282
| |
| }}
| |
| * Magie, W.M. (1963). ''A Source Book in Physics.'' Harvard: Cambridge MA. pp. 461–464. Partial translation of Seebeck's "Magnetische Polarisation der Metalle und Erze durch Temperatur-Differenz."
| |
| | |
| ==External links==
| |
| *[http://www.dea.icai.upco.es/romano/sp4/tpares_all.pdf A Biography of Seebeck, includes references]
| |
| | |
| {{Authority control|VIAF=54931229}}
| |
| | |
| {{Persondata <!-- Metadata: see [[Wikipedia:Persondata]]. -->
| |
| | NAME = Seebeck, Thomas Johann
| |
| | ALTERNATIVE NAMES =
| |
| | SHORT DESCRIPTION = German physcist
| |
| | DATE OF BIRTH = 9 April 1770
| |
| | PLACE OF BIRTH = [[Reval]]
| |
| | DATE OF DEATH = 10 December 1831
| |
| | PLACE OF DEATH = Berlin
| |
| }}
| |
| {{DEFAULTSORT:Seebeck, Thomas Johann}}
| |
| [[Category:1770 births]]
| |
| [[Category:1831 deaths]]
| |
| [[Category:German physicists]]
| |
| [[Category:Estonian physicists]]
| |
| [[Category:Baltic-German people]]
| |
| [[Category:Members of the Prussian Academy of Sciences]]
| |
| [[Category:People from Tallinn]]
| |
| [[Category:People from the Governorate of Estonia]]
| |
| [[Category:University of Göttingen alumni]]
| |
| [[Category:19th-century physicists]]
| |
Alyson Meagher is the title her parents gave her but she doesn't like when people use her full title. Mississippi is exactly where her house is but her husband wants them to move. Credit authorising is how he makes cash. To perform lacross is 1 of the issues she loves most.
Also visit my blog post; good psychic (http://drive.ilovetheory.com/)