ELI5: What is a tectonic plate and why does it move?

Imagine the Earth is like a giant, hard-boiled egg. The shell of the egg is like Earth's crust, which is broken into big pieces called tectonic plates.

Think of these plates like puzzle pieces that cover the whole Earth. You're standing on one of these puzzle pieces right now! Your house, your school, everything!

But, unlike a puzzle, these pieces aren't still. They move very slowly – like your fingernails growing!

So, why do they move?

Imagine you're boiling water in a pot. The water at the bottom gets hot and rises, while the cooler water at the top sinks. This is called convection.

Underneath the Earth's crust is a layer of very hot, melted rock called the mantle. The mantle does something similar to the boiling water.

• Hot rock in the mantle rises.
• It pushes the tectonic plates above it.
• Cooler rock sinks back down.

When plates bump, it can cause mountains to form, like the Himalayas! When they slide past each other, it can cause earthquakes, like in California! When they pull apart, they can create new land, like in Iceland. So, even though you don't feel it, the ground beneath your feet is always slowly shifting because of these moving plates!