Q1.
What are clouds? White lumps in the sky, you might say. But what are they made of? The answer is simple — water. But not just any water; clouds are masses of water droplets, ice crystals, or a mixture of both, that are suspended in the atmosphere.
Answer
Clouds are made of water — but not of water vapour. That is the point worth thinking about, and it is where most people go wrong.
| Form of water | Can you see it? | Where it is in the sky |
|---|---|---|
| Water vapour | No — it is completely invisible | Everywhere in the air around you, right now |
| Water droplets | Yes, when there are enough of them together | The white of a low or middle cloud |
| Ice crystals | Yes | High, cold clouds — the thin wispy ones |
So a cloud is a mass of tiny water droplets, ice crystals, or a mixture of both, suspended in the atmosphere. They form when moist air rises, cools, and the invisible vapour condenses on to specks of dust into droplets too small to fall.
Why a cloud floats although water is heavy: the droplets are unimaginably small — thousands of them would fit across the full stop at the end of this sentence. Something that small falls so slowly that the gentlest upward movement of air holds it up. Rain begins only when droplets collide and merge until they are heavy enough to win against the rising air.
Check it yourself: the white plume from a kettle is not steam either. The invisible gap right at the spout is the true steam; the white cloud you see a centimetre away is condensed droplets — a miniature cloud, made in your kitchen.