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Incoming links: Wander Johannes de Haas, 1878–1960 by H. B. G. Casimir
Wander Johannes de Haas Created 2026-10-18 Updated 2026-11-05
Wander Johannes de Haas and Albert Einstein investigated mechanical motion produced by changing the magnetization of a suspended body. Magnetic reversal changes microscopic angular momentum; a compensating rotation of the body tests angular-momentum conservation. Their experiment connected an apparently internal magnetic property with a visible mechanical response. Interpreting a gyromagnetic measurement requires the relation between magnetic moment and angular momentum, rather than treating magnetization as a force acting independently of its microscopic carriers.[ref]
Experimental proof of the existence of Ampère's molecular currents by Albert Einstein and Wander Johannes de Haas. 1915 report, magnetic reversal and mechanical rotation experiment
A physicist who researched magnetism and became a professor at Leiden in 1924.[ref]
Wander Johannes de Haas, 1878–1960 by H. B. G. Casimir. Career paragraphs: PTR research staff 1913–1915; Delft, Groningen and Leiden professorships
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Portrait of Wander Johannes de Haas
. Unknown photographer; Huygens Laboratorium, Universiteit Leiden; reproduced in Dirk van Delft, Heike Kamerlingh Onnes: Een biografie (2005), p. 529. Public domain (author life plus 70 years; published before 1931). Source usage terms, via Wikimedia Commons. Source.,_in_1924_together_with_Willem_Keesom_(1876_-_1956).png){kind=link}