← Things That Run · Lesson 1 of 3
The water cycle
The Sun warms water in seas and lakes, and some of it evaporates into the air as vapour. Higher up, the air is cooler, and the vapour condenses into tiny droplets that make clouds.
When the droplets grow heavy they fall as rain or snow, run into rivers and soak into the ground, and flow back to the sea. Then it starts again. Nothing is used up; the same water goes round.
What turns vapour in the air into cloud droplets?
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