Register to reply

A question about condensation of water

by fluidistic
Tags: condensation, water
Share this thread:
fluidistic
#1
Nov21-09, 06:44 PM
PF Gold
fluidistic's Avatar
P: 3,188
When I put a near 0C water in a glass which is at room temperature (around 25-30C), some water in air (humidity) condensate over the glass. That's what I believe.

I understand this like, the water present in the air as gas has molecules with more energy (kinetic, but overall?) than liquid water. When these fast molecules hit the "cold" glass, they transmit a lot of their energy and hence they change their phase from gas to liquid. Again, that's what I believe. (point me out if I'm wrong)

But why don't it happen even if the glass is at room temperature? In other words, why the water present in the air doesn't condensate on everything? Why the water that evaporates doesn't condensate on any object? I guess it does but much less than if the object is cold, which I can understand, but I can't understand the proportion. By this I mean, I can't understand why a glass at 0C is much, much, much, much cooler than a glass at 20C for the water vapor.

Is there any mathematical formula I can look at?
Thanks in advance... I'm bothered by that.
Phys.Org News Partner Physics news on Phys.org
Mapping the optimal route between two quantum states
Spin-based electronics: New material successfully tested
Verifying the future of quantum computing
russ_watters
#2
Nov22-09, 12:27 AM
Mentor
P: 22,243
Water condenses on an object who'se temperature is less than the dew point of the ambient air. The dew point is the temperature at which the air can no longer hold the moisture in it and the moisture starts to condense. So the object cools the air adjacent to it down to the dew point, causing water to condense and the only place for the condensed water to go is to stick to the object.

This phenomena can be analyzed on a psychrometric chart: http://www.fao.org/docrep/s1250e/S1250EEW.GIF
fluidistic
#3
Nov22-09, 10:18 AM
PF Gold
fluidistic's Avatar
P: 3,188
Thank you very much for the explanation and the link to the chart.


Register to reply

Related Discussions
Thermodynamics water/water vapor question Advanced Physics Homework 1
FRUSTRATING QUESTION: Condensation Reactions with Covalent Bonds Biology, Chemistry & Other Homework 3
Question on the Cauchy Condensation test Calculus 2
Water Cooled PC and Condensation... General Physics 2
Basic question regarding triple point of water and physical properties of water Introductory Physics Homework 9