|Born||23 September 1819
|Died||18 September 1896 (aged 76)
|Known for||Doppler Effect
Armand Hippolyte Louis Fizeau (23 September 1819 – 18 September 1896) was a French physicist.
Fizeau was born in Paris to Louis and Béatrice. His earliest work was concerned with improvements in photographic processes. Following suggestions by François Arago, Léon Foucault and Fizeau collaborated in a series of investigations on the interference of light and heat. In 1848, he predicted the redshifting of electromagnetic waves.
In 1849, Fizeau calculated a value for the speed of light more precise than the previous value determined by Ole Rømer in 1676. He used a beam of light reflected from a mirror eight kilometers away. The beam passed through the gaps between teeth of a rapidly rotating wheel. The speed of the wheel was increased until the returning light passed through the next gap and could be seen.
Fizeau calculated the speed of light to be 313,300 kilometres per second (194,700 mi/s), which was within about five percent of the correct value (299,792.458 kilometers per second). Fizeau published the first results obtained by his method for determining the speed of light in 1849. (See Fizeau-Foucault apparatus.) Fizeau made the first suggestion in 1864 that the "length of a light wave be used as a length standard".
In 1853, Fizeau described the use of the capacitor (sometimes called a "condenser") as a means to increase the efficiency of the induction coil. Later on, he studied the thermal expansion of solids, and applied the phenomenon of interference of light to the measurement of the dilatations of crystals. He became a member of the Académie des Sciences in 1860 and a member of the Bureau des Longitudes in 1878. He died at Venteuil on September 18, 1896.
- Hockey, Thomas (2009). The Biographical Encyclopedia of Astronomers. Springer Publishing. ISBN 978-0-387-31022-0. Retrieved August 22, 2012.
- Hellemans, Alexander; Bryan Bunch (1988). The Timetables of Science. New York City: Simon and Schuster. p. 317. ISBN 0-671-62130-0.
- Poincaré, H. (Part 1, translated by F. K. V.); Vreeland, Frederick V. (Part 2) (1904). "Experiments of MM. Fizeau and Gounelle". Maxwell's Theory and Wireless Telegraphy. New York: McGraw Publishing Co. pp. 52–55.
- Physics part 1 Resnick/Halliday pg.5
- Houdas, Y. (April 1991). "[Doppler, Buys-Ballot, Fizeau. Historical note on the discovery of the Doppler's effect]". Annales de cardiologie et d'angéiologie 40 (4): 209–13. PMID 2053764.
- This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Fizeau, Armand Hippolyte Louis". Encyclopædia Britannica (11th ed.). Cambridge University Press.
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