Book 1, Question 61
Why Are Deserts So Dry? Three Big Reasons!
Deserts are not just hot, they are super dry! The page gives three big reasons: they get very little rain, often less than about 10 inches a year; mountains can cause a rain shadow, where moist air rains on one side and leaves the other side dry; and sinking air holds less moisture, or the land is too far inland for moist ocean winds. The Atacama Desert in Chile is one of the driest places on Earth. Look at a map for a desert beside mountains to spot a rain shadow.
From the book
Page from A Million Whys Book 1
More fun facts
- Most experts say a desert is land that gets no more than 10 inches, or 25 centimeters, of rain and snow a year.
- In a desert, more water usually evaporates than falls as rain.
- The biggest desert in the world is Antarctica. It is covered in ice, but it rarely rains or snows there.
- Deserts are found on every continent and cover about one fifth of Earth's land.
- The whole continental United States could almost fit inside Africa's Sahara desert.
- Mountains can make deserts. When wet winds hit mountains, the rain falls on one side, leaving the far side dry. This is called a rain shadow.
- Deserts can top 100 degrees Fahrenheit in the day and still get cold at night, because there are few clouds to hold in the heat.
- Many deserts formed 8,000 to 10,000 years ago.
Sources: National Geographic Education, National Geographic Kids, NASA Science
Questions kids ask
What is the biggest desert in the world?
Antarctica. Even though it is icy, it gets so little rain and snow that it counts as a desert.
Are all deserts hot?
No. Some deserts have cold winters, and some, like Antarctica, are cold all year.