Deserts
Deserts get less than 250 mm of rain per year.
About this topic
Deserts receive less than about 250 mm of rain a year, so evaporation exceeds rainfall. They aren't all hot: Antarctica is a polar desert. Hot deserts (Sahara, Arabian, Australian) have large daily temperature swings, scorching by day and cold at night because clear skies let heat escape; cold deserts (Gobi) have freezing winters. Features include dunes, wadis (dry river valleys that flood in rare storms), salt pans, oases, playas (dry lake beds), and rocky plateaus (hamada).
Most sand deserts are in fact a minority; many deserts are rocky or gravelly. Wind moves sand by saltation, bouncing grains along the ground and forming dunes whose shape depends on wind direction. Flash floods, though rare, are powerful because dry ground cannot absorb water.
Plants and animals adapt: cacti store water in thick stems, with spines and waxy skins to reduce loss, camels tolerate dehydration, and many animals are nocturnal or burrow. Causes include subtropical high pressure where air sinks and dries, rain shadows and cold ocean currents. Desertification threatens drylands due to overgrazing, deforestation and climate change, affecting hundreds of millions of people. A common misconception is that deserts are lifeless; they host surprisingly rich, specialised ecosystems.
Key ideas
- Hot and cold deserts
- Dunes and oases
- Specialised plants and animals
Quick check
Use cases: where Deserts helps
- Homework: review the key idea behind Deserts before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Deserts without notes.
- Visual learning: play with the interactive lab to see how Deserts changes when you adjust its inputs.
- Teaching a friend: explain Deserts in your own words, then compare your version with the key ideas.
Geography helps with city planning, climate, trade and migration.
Frequently asked questions
What is Deserts?
Deserts get less than 250 mm of rain per year.
What will I learn in Deserts?
Hot and cold deserts. Dunes and oases. Specialised plants and animals.
Is Deserts part of Geography?
Yes. It is one of 40 Geography topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Deserts lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Deserts?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.