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 caus ...

, 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 ...

in the namesake

Fizeau experiment The Fizeau experiment was carried out by Hippolyte Fizeau in 1851 to measure the relative speeds of light in moving water. Fizeau used a special interferometer arrangement to measure the effect of movement of a medium upon the speed of light. ...

Biography

Fizeau was born in Paris to Louis and Beatrice Fizeau. He married into the

de Jussieu De Jussieu, the name of a French family which came into prominence towards the close of the sixteenth century, and was known for a century and a half for the botanists it produced. The following are its more eminent members: *Antoine de Jussieu (1 ...

botanical family. His earliest work was concerned with improvements in photographic processes. Following suggestions by François Arago,

Léon Foucault Jean Bernard Léon Foucault (, ; ; 18 September 1819 – 11 February 1868) was a French physicist best known for his demonstration of the Foucault pendulum, a device demonstrating the effect of Earth's rotation. He also made an early measurement ...

and Fizeau collaborated in a series of investigations on the

interference Interference is the act of interfering, invading, or poaching. Interference may also refer to: Communications * Interference (communication), anything which alters, modifies, or disrupts a message * Adjacent-channel interference, caused by extr ...

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 f ...

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, (visib ...

s. In 1849, Fizeau calculated a value for the speed of light to a better precision than the previous value determined by

Ole Rømer Ole Christensen Rømer (; 25 September 1644 – 19 September 1710) was a Danish astronomer who, in 1676, made the first measurement of the speed of light. Rømer also invented the modern thermometer showing the temperature between two fix ...

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 The Fizeau–Foucault apparatus is either of two types of instrument historically used to measure the speed of light. The conflation of the two instrument types arises in part because Hippolyte Fizeau and Léon Foucault had originally been friends ...

.) 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 The Doppler effect or Doppler shift (or simply Doppler, when in context) is the change in frequency of a wave in relation to an observer who is moving relative to the wave source. It is named after the Austrian physicist Christian Doppler, who d ...

, 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 To ...

. 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 kinetic ...

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, macros ...

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 the ...

in 1860 and a member of the Bureau des Longitudes in 1878. He died at

Venteuil Venteuil () is a commune in the Marne department in north-eastern France. See also *Communes of the Marne department The following is a list of the 613 communes in the French department of Marne. The communes cooperate in the following i ...

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 Exposition Universelle of 1889 () was a world's fair held in Paris, France, from 5 May to 31 October 1889. It was the fourth of eight expositions held in the city between 1855 and 1937. It attracted more than thirty-two million visitors. The ...

. The crater Fizeau on the

far side of the Moon The far side of the Moon is the lunar hemisphere that always faces away from Earth, opposite to the Near side of the Moon, near side, because of synchronous rotation in the Moon's orbit. Compared to the near side, the far side's terrain is ru ...

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