Why is the sea (and sky) blue? (Assuming they are blue because of the same reason)
In: Physics
They are indeed blue for the same reason: it’s because air and water both scatter light. That is, some of the photons “bump into” air/water molecules and get knocked off course. So instead of traveling in a straight line from the sun to some object and then into your eyes, a proportion of photons are traveling a zig-zaggy path through the sky/sea before making it into your eyes. Whatever color those photons have, is the color that the sky and sea seem to have (or actually have – there isn’t a difference), because those are the photons that hit your eyes when you look into the direction of the sky or sea. And it turns out that blue photons get scattered more than other colors. So therefore, both the sea and sky are blue.
This also explains why a glass of water or a small amount of air (e.g. the air inside a room) do not look blue, because only a tiny fraction of photons get scattered for every meter that they travel through air/water, and so it takes quite a long distance before enough photons have gotten scattered.
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