Earth's Rotation Day (January 8)

One weird holiday on January 8 is Earth’s Rotation Day. Check out the other weird January holidays!

History of Earth’s Rotation Day

Well, the earth has been rotating since…. forever. So that history is a bit boring!

The age-old argument about whether the Earth revolves around the sun, or the sun revolves around the Earth, was solved by Galileo. However, the fact that the earth itself rotates all the way around in a day was a different proof entirely.

Leon Foucault, proved that the Earth rotates on its axis on January 8, 1851, when he suspended a lead-filled brass sphere (now called the Foucault Pendulum) from the top of the Pantheon in Paris. He demonstrated that the swing of the pendulum all on its own was because of the Earth’s rotation.

Today, Foucault’s Pendulums are a fixture in science museums around the world. Over the course of a day, the direction the pendulum swings seems to change, slowly moving in a full circle. What we see is actually the earth turning beneath the pendulum. The speed at which the pendulum precesses depends on its latitude. In this video of the Foucault Pendulum at the Orange Coast College Planetarium (with a latitude of 33.7N) the pendulum makes a complete 360 degree precession about once every 43 hours.

Ideas to Celebrate Earth’s Rotation Day

You can always go to your local science museum and check out a Focault pendulum, or you can do these fun activities to celebrate the weird holiday about the earth rotating on its axis.

You might also like these Free DIY Earth Day Crafts & Activities for Kids.