Walter Kaufmann (physicist)
Walter Kaufmann | |
|---|---|
 | |
| Born | June 5, 1871 |
| Died | January 1, 1947 |
| Citizenship | German |
| Known for | Proof of the velocity dependence of mass |
Walter Kaufmann (June 5, 1871, Elberfeld - January 1, 1947, Freiburg im Breisgau) was a German physicist. He is most well known for his first experimental proof of the velocity dependence of mass, which was an important contribution to the development of modern physics, including special relativity.
Life
In 1890/91 he studied mechanical engineering at the technical universities of Berlin and Munich, since 1892 he studied physics at the Universities of Berlin and Munich and in 1894 he attained a doctorate. Starting from 1896 he worked as an assistant at the physical institutes of the Universities of Berlin and Göttingen. Kaufmann habilitated in 1899 and became a professor extraordinarius of physics in at the University of Bonn. After a renewed activity at the Berliner Physikalisches Institut he followed a call as professor ordinarius for experimental physics and leader of the physical institute at the Albertina in Königsberg, where he taught up to his retirement in 1935. Subsequently, he worked as a guest lecturer at the University of Freiburg.[1]
Measurements of velocity dependence of mass
His early work (1901-1903) confirmed for the first time the velocity dependence of the electromagnetic mass of the electron (later called relativistic mass). However, those measurements were not precise enough to differentiate between the Lorentz ether theory of Hendrik Antoon Lorentz and the theory of Max Abraham.
At the end of 1905 he performed experiments that were still more exact. Here Kaufmann was the first to discuss Albert Einstein's theory of special relativity and argued, that although Einstein's theory is based on completely different conditions and is also logically more satisfying, the theory is observationally equivalent to Lorentz's theory. Therefore he spoke of the theory of "Lorentz-Einstein". It is notable that Kaufmann himself interpreted the results of his experiments as a confirmation of Abraham's theory, and a refutation of the Lorentz-Einstein principle of relativity, which for some years weighed heavily against the theories of Lorentz and Einstein. However, Kaufmann's results were criticized by Max Planck and Adolf Bestelmeyer in 1906. So physicists like Alfred Bucherer (1908), Neumann (1914) and others, repeated those experiments and arrived at results which apparently confirmed the "Lorentz Einstein" theory and disproved Abraham's theory. However, it was later pointed out that the Kaufmann-Bucherer-Neumann experiments after 1904 were also not precise enough to distinguish among the theories.[2] [3] [4] [5]
However, this problem occurred only for this kind of experiments. The investigations of the fine structure of the hydrogen lines already in 1917 provided a clear confirmation of the Lorentz-Einstein formula, and the refutation of Abraham's theory.[6].
See also
References
- ^ Hans Kangro (1977), "Kaufmann, Walter", Neue Deutsche Biographie (in German), vol. 11, Berlin: Duncker & Humblot, pp. 352–353
- ^ Zahn, C. T. and Spees, A. A. (1938), "A Critical Analysis of the Classical Experiments on the Variation of Electron Mass", Physical Review, 53 (7): 511–521, Bibcode:1938PhRv...53..511Z, doi:10.1103/PhysRev.53.511
{{citation}}: CS1 maint: multiple names: authors list (link) - ^ Rogers; M. M.; et al. (1940), "A Determination of the Masses and Velocities of Three Radium B Beta-Particles", Physical Review, 57 (5): 379–383, Bibcode:1940PhRv...57..379R, doi:10.1103/PhysRev.57.379
{{citation}}: Unknown parameter|author-separator=ignored (help) - ^ Miller, A.I. (1981), Albert Einstein's special theory of relativity. Emergence (1905) and early interpretation (1905–1911), Reading: Addison–Wesley, ISBN 0-201-04679-2
- ^ Janssen, M., Mecklenburg, M. (2007), V. F. Hendricks; et al. (eds.), Interactions: Mathematics, Physics and Philosophy, Dordrecht: Springer: 65–134
{{citation}}:|contribution=ignored (help); Explicit use of et al. in:|editor=(help); Missing or empty|title=(help)CS1 maint: multiple names: authors list (link) - ^ Pauli, Wolfgang (1921), "Die Relativitätstheorie", Encyclopädie der mathematischen Wissenschaften, 5 (2): 539–776
Publications
- Kaufmann, W. (1901), "Die Entwicklung des Elektronenbegriffs", Physikalische Zeitschrift, 3 (1): 9–15
- Kaufmann, W. (1901), "Die magnetische und elektrische Ablenkbarkeit der Bequerelstrahlen und die scheinbare Masse der Elektronen", Göttinger Nachrichten (2): 143–168
- Kaufmann, W. (1902), "Über die elektromagnetische Masse des Elektrons", Göttinger Nachrichten (5): 291–296
- Kaufmann, W. (1902), "Die elektromagnetische Masse des Elektrons", Physikalische Zeitschrift, 4 (1b): 54–56
- Kaufmann, W. (1903), "Über die "Elektromagnetische Masse" der Elektronen at the Internet Archive", Göttinger Nachrichten (3): 90–103
{{citation}}: External link in|title= - Kaufmann, W. (1905), "Über die Konstitution des Elektrons", Sitzungsberichte der Königlich Preussischen Akademie der Wissenschaften (45): 949–956
- Kaufmann, W. (1906), "Über die Konstitution des Elektrons", Annalen der Physik, 19: 487–553
External links
- The Kaufmann Experiments (Power point presentation)
- http://www-atm.jst.go.jp:8080/16030302_1.html (Japanese)
- Viaje medios de comunicación compras at itfisica.net at itfisica.net (Italian)
- Zeittafel (timetable about physics)
- 1871 births
- 1947 deaths
- German physicists
- German Lutherans
- Mass spectrometrists
- People from Elberfeld
- People from the Rhine Province
- Berlin Institute of Technology alumni
- Technical University Munich alumni
- Humboldt University of Berlin alumni
- Ludwig Maximilian University of Munich alumni
- University of Göttingen alumni
- University of Bonn faculty
- University of Königsberg faculty
- University of Freiburg faculty