Earth's Rotation Day
January 8 · Level 7 · #864 of 2238
This day nudges us to notice something we can't feel: our planet is turning on its axis all the time. It is linked to French physicist Léon Foucault, who found a clever way to make that rotation visible.
How it is celebrated: science fans try pendulum or spinning-top experiments, watch videos about how the planet moves, chat about days and time zones, or simply watch the sunrise and picture the ground turning beneath it.
In 1851 Foucault hung a heavy pendulum from the dome of the Panthéon in Paris, and its swing slowly changed direction as the Earth turned. A year later he gave the name "gyroscope" to his device for showing the planet's rotation.