Thread: Ask a Scientist
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Old 11.08.2011, 20:22
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Re: Ask a Scientist

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But a cup of water or a bath of water both look clear from all angles
But a cloud isn't a single mass of water like a cupful or a bathful, it's a huge number of tiny droplets of water which can reflect and absorb the sunlight entering the cloud in exactly the way that "bigger" lumps of water don't (that's why one can see further in heavy rain than one can in heavy fog.)

Consider being on the tarmac at an airport and looking up to the base of a dull, wet miserable, grey-black overcast cloud (Zurich airport, obviously ), then hopping onto the plane, taking off and climbing up through the cloud,(effectively flying through fog and can't see any detail), then popping out the top of the cloud which is now brillian white.

It's the same cloud, with totally different appearances - under it, it looks dark (most of the light is being absorbed); in it, it's getting progressively lighter as you rise up through it (less and less absorption); above it, it's brilliant white (no absorption, lots of reflection of the sunlight striking it).
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