Boxi Learn › Geography › Stage 4 · Systems and Argument
Why deserts sit at 30°
GEO-2 Places differ, and there are reasonsGEO-3 The Earth is moving
What many people think
Deserts are where it is hottest.
The idea
Air rises at the hot equator, drops its rain, and sinks dry around 30° north and south — where most big deserts are.
Explain it
A friend says the Sahara is a desert because it is so hot. Explain, using rising and sinking air, why the even hotter equator is rainy and the Sahara is dry.
Try at home
Hold a glass of iced water near the steam from a hot drink (or breathe on a cold mirror): cooling air drops its water as drops. Then warm the misted mirror with a hair-dryer — warming air takes the water back.