What is a mountain?
A mountain is a very tall, big bump in Earth’s surface. Mountains can be small hills or very tall peaks that stick up into the sky.
What mountains are made of
- Rocks – deep down most of the mountain is hard rock.
- Layers – rocks often lie in layers, like a layered cake. Different kinds of rock can make up those layers.
- Soil and stones – on top of the rocks there is usually soil, loose stones and little rocks where plants can grow.
How mountains form - three simple ways
- Pushing of Earth plates (folded mountains)
Earth’s outer shell is made of big pieces called plates. When two plates push together, the ground can crumple and fold up like a rug being pushed. That fold makes a mountain.
- Volcanoes
Sometimes hot melted rock from under Earth comes out through a hole. When it piles up and cools, it makes a volcano mountain.
- Blocks pushed up or dropped down
Parts of the ground can break and move up or down. The parts that go up can become blocky mountains.
How mountains change
Rain, wind, ice and rivers slowly wear mountains away. This is called erosion. It can make the mountains rounder or make cliffs and valleys.
Try this easy activity
- Take two books and put a soft cloth between them.
- Push the books toward each other slowly. Watch how the cloth folds up like a mountain.
- Or use playdough: press two lumps of playdough together and push. The middle will crumple up like a mountain fold.
Quick questions to think about
- Is the mountain a volcano or a folded mountain?
- What lives on the mountain? Are there trees or snow?
- How do you think erosion will change the mountain over many, many years?
Mountains are more than just bumps. They are full of stories about Earth’s moves, layers of old rocks, and they change slowly over time.