Whose Birthday Is It? September 18, 2018

Jean Bernard Léon Foucault (1819)

Foucault, a French physicist, invented the Foucault pendulum and used it to provide experimental proof that the Earth rotates on its axis. He improved astronomical instruments, especially the telescope, and with Armand Fizeau took the first clear photograph of the Sun. Foucault is also known for determining the speed of light with extreme accuracy and showing that light travels slower in water than in air. He had originally studied medicine but abandoned it for physics due to a fear of what? More…