Armand Fizea French physicist. Date of Birth: 23.09.1819 Country: France

1. Biography of Armand Fizeau
2. Contributions to Optics
3. Legacy and Death

Biography of Armand Fizeau

Armand Fizeau was a French physicist born on September 23, 1819, in Paris. He studied at the College de France and the Paris Observatory, where he attended lectures by A. Rene and D.F. Arago. Fizeau also independently studied natural sciences.

Contributions to Optics

Fizeau's main research focused on optics. From 1844 to 1847, he observed interference with a large path difference together with J. Foucault, using monochromatic radiation. In 1848, he proposed a method for measuring the speed of celestial bodies by studying the displacement of their emission spectrum lines (using the Doppler effect). In 1849, Fizeau conducted his classic experiment to determine the speed of light in terrestrial conditions using a toothed wheel (the Fizeau method). In 1851, by measuring the speed of light in moving water, he established the influence of the medium's motion on light speed (the Fizeau experiment). This experiment proved that light is partially dragged by the medium, playing an important role in confirming the relativistic formula for velocity addition. Fizeau also developed an interferometric method for determining the coefficient of thermal expansion of solids and the angular diameter of stars. He constructed an interferometric microscope as well. For his contributions, Fizeau was awarded the Rumford Medal in 1866.

Legacy and Death

Armand Fizeau passed away on September 18, 1896, in the Château de Vanteuil, Seine-et-Marne. His experiments and discoveries in optics have left a lasting impact on the field, particularly in understanding the nature of light and its interaction with different media.