Metamorphism

Imagine a little rock sitting in the ground, all by itself. It's been there for a really long time, and it's seen a lot of things happen around it. Sometimes it rains, sometimes it's really hot, and sometimes it's really cold. All of those things can change the rock a little bit, over time.

But sometimes, something very special happens to the rock. It gets squished and squeezed and heated up, all at the same time! This is called "metamorphism."

When the rock gets metamorphosed, it changes in some pretty big ways. It might get bigger or smaller, depending on how much pressure was put on it. It might also get a new shape or pattern on its surface, like lines or swirls or even little crystals. And it might get a totally different color or texture too!

All of these changes happen because the rock is under a lot of stress, from all the pressure and heat. But they also happen very slowly, over a really long time. So if you ever see a metamorphic rock, you can know that it's been through a lot!