Herman Haga ( Oldeboorn, 24 January 1852 –

Zeist Zeist () is the capital and largest town of the municipality of Zeist. The town is located in the Utrecht province of the Netherlands, east of the city of Utrecht. History The town of "Seist" was first mentioned in a charter in the year 83 ...

, 11 September 1936) was a Dutch physicist.

Career

Haga studied physics from 1871 to 1876 at the

University of Leiden Leiden University (abbreviated as ''LEI''; nl, Universiteit Leiden) is a public research university in Leiden, Netherlands. The university was founded as a Protestant university in 1575 by William, Prince of Orange, as a reward to the city of Le ...

. He received his PhD with thesis ''Over de absorptie van stralende warmte door waterdamp'' (On the absorption of radiant heat by water vapor) under the direction of Pieter L. Rijke. From 1886 to 1921 Haga was professor of physics at the

University of Groningen The University of Groningen (abbreviated as UG; nl, Rijksuniversiteit Groningen, abbreviated as RUG) is a Public university#Continental Europe, public research university of more than 30,000 students in the city of Groningen (city), Groningen in ...

, where he designed and oversaw the building of a new physics laboratory, opened in 1892. From 1900 Haga was also the rector of the University of Groningen. He performed experiments on the voltage of the

Weston cell The Weston standard cell is a wet-chemical cell that produces a highly stable voltage suitable as a laboratory standard for calibration In measurement technology and metrology, calibration is the comparison of measurement values deliver ...

; these experiments lead to the modern definition of the

volt The volt (symbol: V) is the unit of electric potential, electric potential difference (voltage), and electromotive force in the International System of Units (SI). It is named after the Italian physicist Alessandro Volta (1745–1827). Defi ...

. With Cornelis Wind, Haga passed X-rays through a 15-micrometer slit as a source with a V-shaped narrowing slit as a target. The target slit was 27 micrometers at the opening and nearly 0 micrometers at the output. Haga and Wind interpreted a diffuse broadening of the X-rays emitted at the narrower end of the slit as a diffraction pattern. Haga was one of the founders of the ''Nederlandse Natuurkundige Vereniging'' (Dutch Physics Association). In addition to Cornelis Harm Wind (1867–1911), Haga's doctoral students include the crystallographer Pieter Terpstra (1886–1973) and Ekko Oosterhuis (1886–1966), who was the second scientist to join the ''

Philips Natuurkundig Laboratorium The Philips Natuurkundig Laboratorium (English translation: ''Philips Physics Laboratory'') or NatLab was the Dutch section of the Philips research department, which did research for the product divisions of that company. Originally located in the ...

''. In 1896 Haga became a member of the

Royal Netherlands Academy of Arts and Sciences The Royal Netherlands Academy of Arts and Sciences ( nl, Koninklijke Nederlandse Akademie van Wetenschappen, abbreviated: KNAW) is an organization dedicated to the advancement of science and literature in the Netherlands. The academy is housed ...

References

External links

* *''This article incorporates information from the article Herman Haga in the Dutch Wikipedia.'' 1852 births 1936 deaths 20th-century Dutch physicists Frisian scientists Leiden University alumni Members of the Royal Netherlands Academy of Arts and Sciences People from Heerenveen University of Groningen alumni 19th-century Dutch physicists {{Physicist-stub