IMO Practice Test — The Water Cycle
6 Questions • 12 min • Olympiad level
12:00
Question 1 of 6
hard
About how much of the Earth's surface is covered by water?
Most of it (about three-quarters)
None
A tiny bit
Exactly half is land
Explanation: Water covers about three-quarters of Earth's surface.
Question 2 of 6
hard
Cutting too many trees can reduce rainfall because trees help return water to the air through their…
Leaves
Roots only
Bark only
Shadows
Explanation: Trees release water vapour from their leaves, aiding rain.
Question 3 of 6
medium
Why does your warm breath make a 'cloud' on a cold morning?
It is sand
You breathe smoke
Your breath freezes to rock
The warm vapour cools and condenses
Explanation: Warm breath condenses in cold air, making a tiny cloud.
Question 4 of 6
hard
Hail is special because the falling water freezes into balls of…
Glass
Sand
Salt
Ice
Explanation: Hail is frozen balls of ice.
Question 5 of 6
hard
Salt is left behind when sea water evaporates. This shows that evaporation lifts up the ___ but not the salt.
Water
Sand
Heat
Air
Explanation: Only the water evaporates; salt stays behind.
Question 6 of 6
hard
Condensation and evaporation are opposite because one turns water to vapour and the other turns vapour to…
Water
Rock
Salt
Air
Explanation: Evaporation makes vapour; condensation turns vapour back to water.