Land can also be described by what covers it: very little, lots of trees, or lots of grass.
Key idea
A desert gets very little rain. A forest is covered with trees. A grassland is wide open land covered with grass, with few trees.
Why it works
Plants need water. Where lots of rain falls, trees can grow into forests. Where less rain falls, grass grows better than trees. Where almost no rain falls, only tough plants like cactuses can live: that is a desert.
Worked example: A cold desert
Antarctica is covered with ice and snow. Can it be a desert?
- A desert is a place with very little rain or snow each year.
- Very little new snow falls in most of Antarctica.
Answer: Yes. It is the biggest desert on Earth.
Common mistake
Children picture every desert as hot and sandy. A desert is about how little rain or snow falls, not about heat or sand. Some deserts are rocky, and some are cold.
For the grown-up. Look at photos of deserts, forests and grasslands together. Ask, "Does it rain a lot here or a little? How can you tell?"