Foucault pendulum

Have you ever played on a swing and noticed that it swings back and forth again and again? This is what we call oscillation. Now imagine a super tall pendulum hanging from the ceiling that also swings back and forth, but this time it doesn't stop like the swing. This is called a Foucault pendulum, named after a smart man named Léon Foucault who made one.

The Foucault pendulum works because the Earth is rotating on its axis. So when the pendulum swings, the Earth is also moving underneath it. This means the pendulum appears to change direction as it swings back and forth. They might have shown you a "tornado in a bottle" before, where you spin the bottle and it creates a swirling effect inside. The same thing happens to the Foucault pendulum because of the Earth's spin.

The time it takes for the pendulum to complete one full swing is called the period. But because the Earth is spinning, the period changes very slowly over time. It can take a whole day or more for the period to change noticeably.

Now, if you are standing in one place watching the Foucault pendulum swing, it looks like the pendulum is moving in a big circle over time. But if you were standing on the North Pole or South Pole, you would see the pendulum only swing back and forth without turning. This is because the Earth's rotation is more obvious at the poles, while it gets smaller toward the equator.

In conclusion, the Foucault pendulum is a cool way to see the Earth's rotation in action. It might look like it's just swinging back and forth, but it's actually traveling with the Earth as it spins through space.