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what has higher air pressure cold or hot water
Think about it this way... If you put your hand over a pot of ice-water
and then over a pot of almost boiling hot water, where would it feel
wetter? It should feel wetter over the almost boiling water because
even before the water starts boiling, it produces a lot of steam.
Steam is just water vapor. You actually will get water vapor from
water of any temperature... it's just that for really cold water, you
get very little of it. The hotter the water is, the more of it will
naturally evaporate into the air, becoming vapor. So the hotter the
water is, the more water vapor there will be in the air above the
water. The part of the total air pressure due to water vapor will thus
be higher. To total pressure is just the sum of the partial pressures
of all of the gases that are present.
(republished on 08/02/06)
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