Insights Blog
-- Browse All Articles --
Physics Articles
Physics Tutorials
Physics Guides
Physics FAQ
Math Articles
Math Tutorials
Math Guides
Math FAQ
Education Articles
Education Guides
Bio/Chem Articles
Technology Guides
Computer Science Tutorials
Forums
Trending
Featured Threads
Log in
Register
What's new
Search
Search
Search titles only
By:
Menu
Log in
Register
Navigation
More options
Contact us
Close Menu
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Forums
Physics
Classical Physics
Thermodynamics
How does evaporation generate cooling? Swamp coolers edition
Reply to thread
Message
[QUOTE="dario2, post: 6854134, member: 733323"] If water evaporates, that means it's become vapor, and vapor should be at 100C or more at normal pressure, right? So the molecules that left had to be at 100C to leave. If the average temperature was 35C, each gram of water being evaporated reduces nine other grams' average temperature by 7.22C, am I correct? 100C - 35C = 65C. And 65C / 9 = 7.22C This could explain why evaporative cooling works so well on a solution/surface that is 35C average temperature, such as human skin, but it doesn't explain the cooling on a solution that is 99C average temperature, such as the pot of water on the stove. Because if the average temperature of the water was 99C, then each gram being evaporated would only reduce nine other grams' temperature by 0.11C. And if the water reaches 100C before evaporating, that would mean there's no cooling effect from evaporation. You mentioned the heat of vaporization is 540 calories per gram of water, that is for water that is already at 100C, correct? That is it takes a further 540 calories per gram to fully evaporate that 1g of water that is already at 100C. And since that's enough to heat 1g of water by 540C, that would mean each gram of water evaporated also cools another remaining 9g by a further 60C from my previous calculation. 540C / 9 = 60C. Correct? I assume this is what you meant when you said that the electrical bonds between molecules must be broken in order to cause evaporation, and presumably this would account for a much larger part of the cooling process. But my question is, where does this energy go after it's used to break these electrical bonds? Is it contained in the vapor molecules somehow in a form other than heat? And what is the process by which it eventually turns back into heat during condensation? [/QUOTE]
Insert quotes…
Post reply
Forums
Physics
Classical Physics
Thermodynamics
How does evaporation generate cooling? Swamp coolers edition
Back
Top