Christian Christiansen (9 October 1843– 28 November 1917) was a Danish physicist. Christiansen first taught at the local polytechnical school. In 1886, he was appointed to a chair for physics at the

University of Copenhagen The University of Copenhagen (, KU) is a public university, public research university in Copenhagen, Copenhagen, Denmark. Founded in 1479, the University of Copenhagen is the second-oldest university in Scandinavia, after Uppsala University. ...

. He mainly studied

radiant heat Thermal radiation is electromagnetic radiation emitted by the thermal motion of particles in matter. All matter with a temperature greater than absolute zero emits thermal radiation. The emission of energy arises from a combination of electro ...

and

optical dispersion Dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency. Sometimes the term chromatic dispersion is used to refer to optics specifically, as opposed to wave propagation in general. A medium having this common ...

, discovering the Christiansen effect and the Christiansen filter. Around 1917, he discovered the anomalous dispersion of numerous dyes, including aniline red ( fuchsine), by recording absorption spectra. In 1884, he confirmed the

Stefan–Boltzmann law The Stefan–Boltzmann law, also known as ''Stefan's law'', describes the intensity of the thermal radiation emitted by matter in terms of that matter's temperature. It is named for Josef Stefan, who empirically derived the relationship, and Lu ...

. Christiansen was elected a member of the

Royal Swedish Academy of Sciences The Royal Swedish Academy of Sciences () is one of the Swedish Royal Academies, royal academies of Sweden. Founded on 2 June 1739, it is an independent, non-governmental scientific organization that takes special responsibility for promoting nat ...

in 1902. He was doctoral advisor to

Niels Bohr Niels Henrik David Bohr (, ; ; 7 October 1885 – 18 November 1962) was a Danish theoretical physicist who made foundational contributions to understanding atomic structure and old quantum theory, quantum theory, for which he received the No ...

. In 1912, he retired and Martin Knudsen became professor.

Works

* Two-volume physics textbook: ** ** (Exists in some libraries.) * Two-volume introduction to

mathematical physics Mathematical physics is the development of mathematics, mathematical methods for application to problems in physics. The ''Journal of Mathematical Physics'' defines the field as "the application of mathematics to problems in physics and the de ...

: ** ** (Exists in some libraries.) ** Translation into German: ** Translation of the German into English: * *

References

External links

* Physics Tree
Christian Christiansen Details
* 19th-century Danish physicists 20th-century Danish physicists Optical physicists 1843 births 1917 deaths Members of the Royal Swedish Academy of Sciences Members of the Royal Society of Sciences in Uppsala {{Denmark-scientist-stub