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why does the people in the cold country breathe out air?
Well, all people breathe out air, but I think what you're asking is why you can see
your breath if it's really cold out. And the reason may not be what you
expect. When you can "see your breath", it's not actually the air that
you're seeing at all. Instead, it's the water vapor in the air. Inside
your lungs is a very damp place, so when you breath out, your breath
has a lot of water in it. If it's very cold outside, then the water
vapor in your breath will condense, changing from a gaseous vapor into
tiny liquid water droplets. These water droplets are what you see.
(published on 10/22/2007)
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