Anders and Knut Ångström

Ångström Laboratory is named after Anders Jonas Ångström and his son Knut Ångström, both of whom were professors at Uppsala University in the 19th century.

Anders Jonas Ångström

The Ångström family descended from Anders Persson, a freeholder in Ånge in Borgsjö parish in Medelpad. The family name passed to the son, Johan, a preacher at Lögdö Ironworks, who later became an assistant vicar in Sättna in Medelpad. His son, Anders Jonas Ångström (1814–1874), was born in Lögdö. After schooling in Härnösand, Johan came to Uppsala in 1833, where his successful studies led to a doctor’s degree in physics in 1839. However, he first devoted himself to astronomy, working as an astronomer for a few years before being appointed a professor of physics in 1858, the same year that the physics department finally acquired its own permanent premises.

Anders Jonas Ångström introduced regular Anders Jonas Ångström introduced regular laboratory studies for the students. In his research he combined excellent experimental skills with an intimate knowledge of mathematics. He was multitalented. Among other things, he studied thermal conductivity, heat theory and earth magnetism, but above all he became known as one of the founders of spectroscopic science.

He conducted in-depth studies of the sun’s spectrum, especially the Fraunhoferska lines. Recherches sur le spectre solaire, published in 1868 and one of the classic works in spectroscopy, long was a standard text in the field. He also became the first to study spectra from the northern lights. He introduced the unit for light wavelengths later adopted as an international unit called the angstrom unit (1 Å = 0.1 nanometre).

Knut Ångström

Naturally, Anders Jonas Ångström’s son, Knut Ångström (1857–1910), studied at Uppsala University. After receiving his licentiate degree in 1884, he went to Strassburg and spent time with August Kundt, which led to his doctorate and lectureship in Uppsala in 1885. For a few years he served at the College of Stockholm, where he made major contributions in planning and building up the physics department.

Knut returned to Uppsala as an associate professor in physics in 1891 and became a professor in 1896. His research included heat and solar radiation, particularly what is known as the solar constant. In 1895 and 1896 he made an in-depth study of solar radiation in Tenerife, in the Canary Islands, measuring the solar constant. Closely associated with this research were his studies of solar radiation absorption in the infrared part of the spectrum caused by water vapor, carbon dioxide and ozone.

Knut Ångström was a prominent instrument designer, and his pyrheliometer for measurement of direct beam solar irradiance was adopted in 1905 as the official standard. The instrument was later modified and is still used as a reference. Knut Ångström also carried out the construction of a new, well-organised physics department in Uppsala, inaugurated in 1908. He was a member of the Academy of Sciences’ Nobel Committee for Physics from its inception in 1901 and became its chair in 1905.

More about the works of Anders and Knut Ångström

An extensive presentation of Anders Jonas Ångström’s and Knut Ångström’s scientific works is published in Acta Universitatis Upsaliensis, writings concerning Uppsala University, C. Organisation och historia, 60. Angstroms, far och son, 1997.

Text: Professor emeritus Olof Beckman