Physicist — Jean Bernard Léon Foucault (Paris 1819 – 1868) was a French physicist best known for the experimental demonstration of the Earth’s rotation. Initially set on studying medicine, he abandoned it to devote himself to experimental physics, in which he excelled through practical skill. In 1851 he carried out in Paris the famous pendulum experiment that bears his name, directly and visibly showing the Earth’s rotation. The following year he invented the gyroscope and made ever more accurate measurements of the speed of light, showing that it is lower in water than in air, in support of the wave theory. He also studied the currents induced in solid conductors, today called Foucault currents.
Trivia
The pendulum he hung from the dome of the Panthéon in Paris in 1851 allowed people, for the first time, to ‘see’ the Earth’s rotation with their own eyes, without astronomical observations.
Theories and contributions
- Foucault pendulum — The plane of oscillation of a long pendulum slowly rotates because of the Earth’s rotation, with a period depending on latitude: .
- Foucault (eddy) currents — Currents induced in conducting masses by a varying magnetic flux, dissipating energy through the Joule effect.
- Speed of light in media — Using a rotating mirror, he measured that light travels more slowly in water than in air, confirming its wave nature.
Featured in chapters
Linked atoms
4 linked atoms.