Asked by: Charlie Mack, Uckfield

As warm air rises, the water vapour remains invisible until the air cools enough for it to condense into water droplets. The altitude where that happens marks the bottom of the cloud. Providing that more air feeds in from below, new cloud will form there and preserve the flat bottom. The existing cloud is pushed upwards, forming a fluffy top.

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luis villazon
Luis VillazonQ&A expert

Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.

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