⛰️ Can Earth's shell build mountains?

Look out the window at the hills and houses. Everything sits on the ground under our car. Shh, here's a secret: that ground is moving right now! Earth has a hard outside, like the shell on an egg. But the shell is cracked into giant pieces.

Seven or eight big ones, and lots of little ones! When two pieces push into each other, the rock has nowhere to go. So it crumples and squishes upward. It's like pushing a blanket together on your bed. It bunches up into a bump!

Big bumps of rock become mountains! But the pieces move slower than a sleepy snail. Each year, only as far as your fingernails grow! Can you wiggle your fingernails? Mountains take a very, very long time to build.

On this road, the ground under our car feels still and solid. But it is moving, very slowly! Earth's hard outer shell is cracked into giant pieces, like a broken eggshell, and those pieces slide around. So can moving pieces of ground build a mountain? Let's follow one giant piece. It carries land and ocean on its back. Long, long ago, it drifted along, slower than slow.

It moved about as fast as your fingernails grow. A snail would win that race every single day! Then it bumped into another giant piece. Neither one would move out of the way. So they kept pushing, year after year after year. The ground where they met had nowhere to go but up. It crumpled and folded, like a rug when you push it against the wall.

Higher and higher it rose, until it became mountains. That's how the tallest mountains in the world grew! Count the hills you can see from the car right now. The giant pieces under us are still slowly pushing today. So mountains are still growing, a tiny bit at a time.