Armand Hippolyte Louis Fizeau FRS

FRSE Fellowship of the Royal Society of Edinburgh (FRSE) is an award granted to individuals that the Royal Society of Edinburgh, Scotland's national academy of science and letters, judged to be "eminently distinguished in their subject". This soci ...

MIF (; 23 September 181918 September 1896) was a French

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

, best known for measuring the

speed of light The speed of light in vacuum, commonly denoted , is a universal physical constant that is important in many areas of physics. The speed of light is exactly equal to ). According to the special theory of relativity, is the upper limit fo ...

in the namesake Fizeau experiment.

Biography

Fizeau was born in Paris to Louis and Beatrice Fizeau. He married into the de Jussieu botanical family. His earliest work was concerned with improvements in photographic processes. Following suggestions by

François Arago Dominique François Jean Arago ( ca, Domènec Francesc Joan Aragó), known simply as François Arago (; Catalan: ''Francesc Aragó'', ; 26 February 17862 October 1853), was a French mathematician, physicist, astronomer, freemason, supporter of t ...

, Léon Foucault and Fizeau collaborated in a series of investigations on the interference of light and heat. In 1848, he predicted the

redshift In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and simultaneous increase in fr ...

ing of

electromagnetic wave In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visible) ...

s. In 1849, Fizeau calculated a value for the speed of light to a better precision than the previous value determined by Ole Rømer in 1676. He used a beam of light reflected from a mirror 8 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 hit the next tooth and could not be seen. Fizeau calculated the speed of light to be , which was within 5% of the correct value ( 299,792.458 kilometers per second). Fizeau published the first results obtained by his method for determining the

in 1849. (See Fizeau–Foucault apparatus.) Fizeau made the first suggestion in 1864 that the "speed of a light wave be used as a length standard". Fizeau was involved in the discovery of the Doppler effect, which is known in French as the Doppler–Fizeau effect. In 1853, Fizeau described the use of the

capacitor A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals. The effect of ...

(sometimes called a "condenser") as a means to increase the efficiency of the

induction coil An induction coil or "spark coil" ( archaically known as an inductorium or Ruhmkorff coil after Heinrich Rühmkorff) is a type of electrical transformer used to produce high-voltage pulses from a low-voltage direct current (DC) supply. p.98 ...

. Later on, he studied the

thermal expansion Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions. Temperature is a monotonic function of the average molecular kin ...

of solids and applied the phenomenon of interference of light to the measurement of the dilatations of

crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macro ...

s. He became a member of the

Académie des Sciences The French Academy of Sciences (French: ''Académie des sciences'') is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French scientific research. It was at ...

in 1860 and a member of the

Bureau des Longitudes Bureau ( ) may refer to: Agencies and organizations * Government agency *Public administration * News bureau, an office for gathering or distributing news, generally for a given geographical location * Bureau (European Parliament), the administ ...

in 1878. He died at Venteuil on 18 September 1896. "Fizeau" is one of the 72 names inscribed at the base of Eiffel Tower, and of the 72 scientists and engineers listed on the tower, Fizeau is the only one who was still alive when the tower was opened to the public for the 1889 World's Fair. The crater

Fizeau Armand Hippolyte Louis Fizeau FRS FRSE MIF (; 23 September 181918 September 1896) was a French physicist, best known for measuring the speed of light in the namesake Fizeau experiment. Biography Fizeau was born in Paris to Louis and Beatrice F ...

on the far side of the Moon is named after him.

References

External links

* *
Open Library
{{DEFAULTSORT:Fizeau, Hippolyte 1819 births 1896 deaths Scientists from Paris French physicists Optical physicists Foreign Members of the Royal Society Members of the French Academy of Sciences French Roman Catholics Members of the Royal Society of Sciences in Uppsala

Biography

See also

References

External links