Relive great moments in science on the exact patch of Earth where they took place. Justin Mullins is your guide
Foucault’s pendulum
PANTHÉON, Place du Panthéon, Paris
By the mid 19th century, scientists had long known that the Earth rotates. Yet an uncomfortable puzzle remained. Nobody knew how to demonstrate this rotation in a simple and easy way. Then in 1851, French physicist Léon Foucault devised a way, which he demonstrated publicly by hanging a 28-kilogram bob from the dome of the Panthéon, a mausoleum in Paris. As the pendulum swings, the Earth rotates beneath it, making the…
