Biography:Gustav Kirchhoff

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Gustav Kirchhoff
Born
Gustav Robert Kirchhoff

(1824-03-12)12 March 1824
Königsberg, East Prussia, Kingdom of Prussia
Died17 October 1887(1887-10-17) (aged 63)
Berlin, German Empire
Resting placeAlter St.-Matthäus-Kirchhof, Berlin
Alma materUniversity of Königsberg (Dr. phil.)
Known for
Spouse(s)
  • Clara Richelot
    (m. 1857; died 1869)
  • Luise Brömmel (m. 1872)
Children5
Awards
Scientific career
FieldsThermodynamics, electromagnetism,
graph theory, optics, spectroscopy
Institutions
  • University of Berlin (1847–1850, 1875–1887)
  • University of Breslau (1850–1854)
  • University of Heidelberg (1854–1875)
ThesisUeber den Durchgang eines elektrischen Stromes durch eine Ebene, insbesondere durch eine kreisförmige (1847)
Doctoral advisorFranz Ernst Neumann
Notable students

Gustav Robert Kirchhoff (de; 12 March 1824 – 17 October 1887) was a German physicist and mathematician who contributed to the fundamental understanding of electrical circuits, spectroscopy, and the emission of black-body radiation by heated objects.[3][4] He coined the term black body in 1860.[5]

Several different sets of concepts are named "Kirchhoff's laws" after him, which include Kirchhoff's circuit laws, Kirchhoff's law of thermal radiation, Kirchhoff's diffraction formula, and Kirchhoff's law of thermochemistry.

The Bunsen–Kirchhoff Award for spectroscopy is named after Kirchhoff and his colleague, Robert Bunsen.

Biography

Gustav Robert Kirchhoff was born on 12 March 1824 in Königsberg, Prussia, the son of Friedrich Kirchhoff, a lawyer, and Johanna Henriette Wittke.[6] His family were Lutherans in the Evangelical Church of Prussia.

Kirchhoff studied at the University of Königsberg, where he attended the mathematico-physical seminar directed by C. G. J. Jacobi,[7] Franz Ernst Neumann, and Friedrich Julius Richelot. In 1845, while a student, Kirchhoff formulated two circuit laws—which are now ubiquitous in electrical engineering. He completed this study as a seminar exercise; it later became his doctoral thesis, supervised by Neumann.

In 1847, Kirchhoff graduated from the University of Königsberg and became a Privatdozent (unsalaried lecturer) at the University of Berlin, where he stayed until 1850 when he was offered a professorship at the University of Breslau. In 1854, he was called to the University of Heidelberg, where he collaborated with Robert Bunsen in spectroscopic work. In 1875, Kirchhoff returned to Berlin, where he remained until his death in 1887.

In 1857, Kirchhoff married Clara Richelot, the daughter of his mathematics professor Richelot; the couple had five children. In 1872, after Clara's death in 1869, he married Luise Brömmel.[8]

In 1864, Kirchhoff was elected a Member of the American Philosophical Society.[9] In 1884, he became a Foreign Member of the Royal Netherlands Academy of Arts and Sciences.[10]

Kirchhoff died on 17 October 1887 in Berlin at the age of 63. He is buried at Alter St.-Matthäus-Kirchhof (Old St. Matthew's Cemetery) in Schöneberg, Berlin (just a few meters from the graves of the Brothers Grimm).

Research

Black-and-white image of two middle-aged men, either one leaning with one elbow on a wooden column in the middle. Both wear long jackets, and the shorter man on the left has a beard.
Kirchhoff (left) and Robert Bunsen, c. 1850

In 1857, Kirchhoff calculated that an electric signal in a resistanceless wire travels along the wire at the speed of light.[11][12]

In 1859, Kirchhoff proposed a law of thermal radiation, and gave a proof in 1861.

Together, Kirchhoff and Bunsen improved on Joseph von Fraunhofer's 1814 spectroscope, which Kirchhoff used to pioneer the identification of the elements in the Sun, showing in 1859 that the Sun contains sodium. Kirchhoff and Bunsen discovered caesium and rubidium in 1861.[13]

Kirchhoff contributed greatly to the field of spectroscopy by formalizing three laws that describe the spectral composition of light emitted by incandescent objects, building substantially on the discoveries of David Alter and Anders Jonas Ångström. In 1862, he was awarded the Rumford Medal "for his researches on the fixed lines of the solar spectrum, and on the inversion of the bright lines in the spectra of artificial light".[lower-alpha 1]

Kirchhoff also contributed to optics, carefully solving the wave equation to provide a solid foundation for Huygens' principle (and correct it in the process).[15][16]

Kirchhoff's circuit laws

Main article: Kirchhoff's circuit laws

Kirchhoff's first law At any node in an electrical circuit where current can branch, the sum of the currents leaving the node is equal to the sum of the currents entering the node. The second law is that the algebraic sum of the potential drops along a closed circuit, taken in any direction of flow, is equal to zero.[17]

Kirchhoff's three laws of spectroscopy

See also: Physics:History of spectroscopy
Visual depiction of Kirchhoff's laws of spectroscopy
  1. A solid, liquid, or dense gas excited to emit light will radiate at all wavelengths and thus produce a continuous spectrum.
  2. A low-density gas excited to emit light will do so at specific wavelengths, and this produces an emission spectrum.
  3. If light composing a continuous spectrum passes through a cool, low-density gas, the result will be an absorption spectrum.

Kirchhoff did not know about the existence of energy levels in atoms. The existence of discrete spectral lines had been known since Fraunhofer discovered them in 1814. That the lines formed a discrete mathematical pattern was described by Johann Balmer in 1885. Joseph Larmor explained the splitting of the spectral lines in a magnetic field known as the Zeeman Effect by the oscillation of electrons.[18][19] These discrete spectral lines were not explained as electron transitions until the Bohr model of the atom in 1913, which helped lead to quantum mechanics.

Kirchhoff's law of thermal radiation

It was Kirchhoff's law of thermal radiation in which he proposed an unknown universal law for radiation that led Max Planck to the discovery of the quantum of action leading to quantum mechanics.

Kirchhoff's law of thermochemistry

Kirchhoff showed in 1858 that, in thermochemistry, the variation of the heat of a chemical reaction is given by the difference in heat capacity between products and reactants:

(∂ΔH∂T)p=ΔCp.

Integration of this equation permits the evaluation of the heat of reaction at one temperature from measurements at another temperature.[20][21]

Kirchhoff's theorem in graph theory

Kirchhoff also worked in the mathematical field of graph theory, in which he proved Kirchhoff's matrix tree theorem.

Works

See also

Notes

  1. ↑ Kirchhoff's banker, on hearing that Kirchhoff had identified the elements present in the Sun, remarked "of what use is gold in the Sun if it cannot be brought to Earth?" Kirchhoff deposited his prize money (gold sovereigns) with the banker, saying "here is gold from the Sun."[14]

References

  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 "Gustav Kirchhoff - The Mathematics Genealogy Project". https://www.genealogy.math.ndsu.nodak.edu/id.php?id=46968. 
  2. ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 "Gustav Robert Kirchhoff - Physics Tree". https://academictree.org/physics/peopleinfo.php?pid=25612. 
  3. ↑ Marshall, James L.; Marshall, Virginia R. (2008). "Rediscovery of the Elements: Mineral Waters and Spectroscopy". The Hexagon: 42–48. http://www.chem.unt.edu/~jimm/REDISCOVERY%207-09-2018/Hexagon%20Articles/bunsen%20and%20spectroscopy.pdf. Retrieved 31 December 2019. 
  4. ↑ Waygood, Adrian (19 June 2013) (in en). An Introduction to Electrical Science. Routledge. ISBN 9781135071134. https://books.google.com/books?id=8qHGRTC7h-MC&pg=PT79. 
  5. ↑ Schmitz, Kenneth S. (2018). Physical Chemistry. Elsevier. pp. 278. ISBN 9780128005996. 
  6. ↑ Kondepudi, Dilip; Prigogine, Ilya (5 November 2014) (in en). Modern Thermodynamics: From Heat Engines to Dissipative Structures. John Wiley & Sons. pp. 288. ISBN 9781118698709. https://books.google.com/books?id=SPU8BQAAQBAJ&pg=PA288. 
  7. ↑ Hockey, Thomas (2009). "Kirchhoff, Gustav Robert". The Biographical Encyclopedia of Astronomers. Springer Nature. ISBN 978-0-387-31022-0. http://www.springerreference.com/docs/html/chapterdbid/58778.html. Retrieved 22 August 2012. 
  8. ↑ "Gustav Robert Kirchhoff – Dauerausstellung". Kirchhoff-Institute for Physics. http://www.kip.uni-heidelberg.de/oeffwiss/kirchhoff. "Am 16. August 1857 heiratete er Clara Richelot, die Tochter des Königsberger Mathematikers ... Frau Clara starb schon 1869. Im Dezember 1872 heiratete Kirchhoff Luise Brömmel." 
  9. ↑ "APS Member History". https://search.amphilsoc.org/memhist/search?creator=&title=&subject=&subdiv=&mem=&year=1864&year-max=1864&dead=&keyword=&smode=advanced. 
  10. ↑ "G. R. Kirchhoff (1824–1887)". Royal Netherlands Academy of Arts and Sciences. http://www.dwc.knaw.nl/biografie/pmknaw/?pagetype=authorDetail&aId=PE00001261. 
  11. ↑ Kirchhoff, Gustav (1857). "On the motion of electricity in wires". Philosophical Magazine 13: 393–412. 
  12. ↑ Graneau, Peter; Assis, André Koch Torres (1994). "Kirchhoff on the motion of electricity in conductors". Apeiron 1 (19): 19–25. http://www.ifi.unicamp.br/~assis/Apeiron-V19-p19-25%281994%29.pdf. 
  13. ↑ Weeks, Mary Elvira (1956). The discovery of the elements (6th ed.). Easton, PA: Journal of Chemical Education. https://archive.org/details/discoveryoftheel002045mbp. 
  14. ↑ Asimov, Isaac, The Secret of the Universe, Oxford University Press, 1992, p. 109
  15. ↑ Baker, Bevan B.; and Copson, Edward T.; The Mathematical Theory of Huygens' Principle, Oxford University Press, 1939, pp. 36–38.
  16. ↑ Miller, David A. B.; "Huygens's wave propagation principle corrected", Optics Letters 16, 1370–1372, 1991
  17. ↑ Corso di Fisicia 2 author Paul A .Tipler
  18. ↑ Buchwald, Jed Z.; and Warwick, Andrew; editors; Histories of the Electron: The Birth of Microphysics
  19. ↑ Larmor, Joseph (1897), "On a Dynamical Theory of the Electric and Luminiferous Medium, Part 3, Relations with material media", Philosophical Transactions of the Royal Society 190: 205–300, doi:10.1098/rsta.1897.0020, Bibcode: 1897RSPTA.190..205L 
  20. ↑ Laidler, Keith J.; and Meiser, J. H.; "Physical Chemistry", Benjamin/Cummings 1982, p. 62
  21. ↑ Atkins, Peter; and de Paula, J.; "Atkins' Physical Chemistry", W. H. Freeman, 2006 (8th edition), p. 56
  22. ↑ Merritt, Ernest (1895). "Review of Vorlesungen über mathematische Physik. Vol. IV. Theorie der Wärme by Gustav Kirchhoff, edited by Max Planck". Physical Review (American Physical Society): 73–75. https://books.google.com/books?id=wx7OAAAAMAAJ&pg=PA73. 

Bibliography

Further reading



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