Knut Ångström (1857 - 1910)

Knut ÅngströmPhysicist Knut Ångström was a technical genius who designed simple, inexpensive and easy to use measuring instruments that made Uppsala an international centre for solar research. Ångström also proved that there is ozone in the Earth’s atmosphere, and he suspected that there was a causal link between the amount of atmospheric ozone and climate variation.

Knut Ångström was born into a scientific environment in Uppsala. His father was Professor of Physics Anders Ångström, who died when Knut was 17 years old, but whose colleague and successor Robert Thalén then became Knut’s guardian. All three men were precision measurement experts with a focus on solar research and measurement of radiation.

Knut Ångström’s vision was that research and teaching should become more closely integrated. He was inspired in this by his experience at the more forward thinking Stockholm University College, where he became physics teacher in 1885. Eleven years later he succeeded Thalén as professor at Uppsala and could gradually begin to modernise the physics department.

Instruments for those with limited resources

Knut Ångström applied his unusual technical talents to constructing and improving instruments for spectroscopy. The institution had limited resources, so he always tried to find ways of making the instruments inexpensive, simple and easy to use – aspects that were also appreciated by many outside the institution. The standardised methods of measurement made possible by Ångström’s instruments led to the recognition of Uppsala as an international centre for solar research.

The relationship between ozone and climate

Ångström made laboratory measurements of ozone’s ability to absorb radiation, and demonstrated that ozone occurs in the atmosphere. He also suspected that the amount of atmospheric ozone could affect the climate, but that further research over many years would be needed to test this hypothesis – something that he was completely correct about.

1885–1891     Physics teacher at Stockholm University College
1896               Professor of Physics at Uppsala University
1901               Member of the Royal Swedish Academy of Sciences’ Nobel Committee for
                       Physics; chair of the Committee from 1905
1908               Modernises the Physics Department at Uppsala University

Knut Ångström’s pyrheliometer

The compensating pyrheliometer is an instrument developed at the beginning of the 20th century by Knut Ångström to measure the intensity of the Sun’s light. At the Solar Congress in Oxford in 1905 the Ångström scale for measuring intensity, which was based on this instrument, was adopted as an international standard and remained so until 1957.



Photo: Mikael Wallerstedt