Fizeau biography samples

The French physicist Hippolyte Armand Louis Fizeau is best remembered as the first to measure the speed of light without any recourse to astronomical observations.

HE French physicist Hippolyte Fizeau was the first to have directly measured the velocity of light in He discovered the shift in wavelength produced by.

Hippolyte Fizeau was born in Paris on Sept. After a lengthy journey had restored him to health, he turned again to scientific studies. This time, however, he did not work for a degree, and instead of medicine he concentrated on physics. It was mainly the experimental verification of theories that interested Fizeau, and he soon had a laboratory equipped for himself at home.

His first achievement was an improvement on the daguerreotype process, a method discovered by Louis Daguerre in to produce photographic images. Fizeau substituted bromine for the iodine used by Daguerre. Together they collaborated to perfect the art for the use of celestial photography. The first authentic photograph of the disk of the sun came through their combined efforts.

It was in the field of optics that Fizeau earned a lasting reputation. If the wave theory was true, the velocity of light had to be greater in moving media, such as water flowing in a tube. The project implied the working out of a terrestrial method of measuring the speed of light, and Arago suggested that this could be done by using a rotating mirror.

Fresnel and Foucault began to work together on the project, but the actual measurements were carried out individually. Meanwhile, Fizeau hit upon the cogwheel method of measuring the speed of light and by September obtained the value of , kilometers per second. His measurements with the rotating mirror were communicated to the academy in May , almost simultaneously with those of Foucault.

During the intervening months Fizeau had also succeeded in measuring the change of the velocity of light in a rapidly flowing column of water, which greatly strengthened belief in the wave theory of light.