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Q & A: Water Vapor - Some like it hot; some like it cold.

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Most recent answer: 10/22/2007
Q:
what has higher air pressure cold or hot water
- Anonymous
A:
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.

-Tamara

(published on 10/22/2007)

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