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Chem11
Joined: 21 Apr 2001
Posts: 1386
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 Wed Jul 11, 2001 7:49 pm
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Well, you've truly outdone yourself this time, Cydoniaquest. You're simply not going to be able to come up with a more depraved, soul-sickening post than the one above.
Congratulations.
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theseeker
Joined: 25 Jul 2000
Posts: 3403
Location: Damnit...I'm a doctor jim |
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Wed Jul 11, 2001 8:36 pm
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One more time cy, and listen this time....
The air (mainly nitrogen and oxygen) no more has a holding capacity for water vapor, than, say, water vapor has for nitrogen. The atmosphere is a mixture of gases. While saturation (which involves bonds between different molecules) is a real phenomenon in liquids it does not describe the interaction of atmospheric constituents.
If the (other gases of the) air were removed, leaving everything else the same, condensation and evaporation would proceed as before (the air was irrelevant to the behavior).
Water molecules are constantly coursing back and forth between phases (another word for the three states: vapor, liquid, and solid). If more molecules are leaving a liquid surface than arriving, there is a net evaporation; if more arrive than leave, a net condensation. It is these relative flows of molecules which determine whether a cloud forms or evaporates, not some imaginary holding capacity that nitrogen or oxygen have for water vapor.
Evaporation increases with temperature, not because the holding capacity of the air changes, but because the more energetic molecules can evaporate more readily (with, of course, the caveat that evaporation is also influenced by things other than temperature, as described above).
If that explanation is not simple enough when the temperature drops below the dew-point temperature, there is a net condensation and a cloud forms.
The idea that it is the air which determines the amount of water vapor which can be present through some sort of holding capacity is an eighteenth century idea which was shown to be false both empirically and theoretically about two hundred years ago! The fact that it is still taught in our schools and defended by teachers and professors, is a testimony to the mindless persistence of myth.
references:
Adams, A. W., 1973: A Textbook of Physical Chemistry. Academic Press, New York, 1079 pp.
Bohren, C. F., 1987: Clouds in a Glass of Beer: Simple Experiments in Atmospheric Physics. Wiley Pub., New York, 195 pp.
Bohren, C. F., 1997: Personal communication. The Pennsylvania State University, University Park, PA.
Bohren, C. F., and B. A. Albrecht, 1998: Atmospheric Thermodynamics. Oxford University Press, New York, NY.
Brutsaert, W., 1991: Evaporation into the Atmosphere: Theory, History, and Applications. Kluwer Academic Publishers, Boston, 299 pp.
Cardwell, D. S. L., ed., 1968: John Dalton and the Progress of Science. Manchester University Press, Manchester, UK, 352 pp.
Dalton, J., 1803: Memoirs Manchester Phil. Soc., 5, 550.
Greenaway, F., 1966: John Dalton and the Atom. Cornell University Press, Ithaca, NY, 244 pp.
Nese, J., L. Grenci, D. Mornhinweg, and T. Owen, 1996: A World of Weather: Fundamentals of Meteorology. Kendall/Hunt Publishing Co., Dubuque, IA, pp.
Ostwald, W., 1891: Solutions. Longmans, Green, and Co., New York, NY, 316 pp.
Rogers, R. R., and M. K. Yau, 1989: A Short Course in Cloud Physics. Pergamon Press, New York, 293 pp.
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Thermit
Joined: 08 Jul 2000
Posts: 3136
Location: Texas |
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Wed Jul 11, 2001 10:20 pm
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Bohren, C. F., 1987: Clouds in a Glass of Beer: Simple Experiments in Atmospheric Physics.
Ahhh, it's all starting to make sense now...
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cydoniaquest
Joined: 12 Aug 2000
Posts: 797
Location: nowhere |
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Wed Jul 11, 2001 10:38 pm
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....And what's your point again Seeker?
Maybe it will help if you look at it this way:
Water exists in three states in the atmosphere:
1.) Water vapor (gaseous, molecular state)
2.) Liquid state (after condensation occurs upon saturation)
3.) Crystalline, solid state....either going directly to a solid from a gas through the process of sublimation or to a solid from the liquid state through the process of condensation and freezing and accretion (ie...snow and hail).
The atmosphere contains water vapor in its gaseous state (ie. a gas) just as oxygen and nitrogen or any other trace gas and particulate material is held in the atmosphere.....by the pull of the earth's gravity.
So what's your point?
When there is more water vapor in the atmosphere than temperature and pressure will allow, we get molecules of water combining in a process called condensation and we have visible moisture as temperature approaches dewpoint.
What don't you agree with here, Mr. Wizard besides my choice in cartoonery?
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theseeker
Joined: 25 Jul 2000
Posts: 3403
Location: Damnit...I'm a doctor jim |
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Wed Jul 11, 2001 10:39 pm
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beer is the breakfast of champions... 
Cy, air does not hold water vapor,that's my point and contention and I've said it 3 times now... condensation and evaporation would exist in a vaccuum totally devoid of air !!! Therefore air is holds no water vapor...are you ok ? you didn't read anything I posted, do I need to hightlight the important parts in red ???
man this is like battle of the network-textbooks !
[Edited 1 times, lastly by theseeker on 07-11-2001] |
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cydoniaquest
Joined: 12 Aug 2000
Posts: 797
Location: nowhere |
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Wed Jul 11, 2001 10:57 pm
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Seeker...talk to me man....I'm loosing you once again to vague beer references.....
How do you answer my questions or respond to my statements? Agree? Disagree? And why or why not? You're loosing me again with the beer stuff.
Don't make me post the poop shooting pic again....I've got more where that came from, ya know!
If you stay on topic I think we might make some headway, or we can go back to wise-ass comments, and muppet pics ...your choice.
[Edited 1 times, lastly by cydoniaquest on 07-11-2001] |
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cydoniaquest
Joined: 12 Aug 2000
Posts: 797
Location: nowhere |
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Wed Jul 11, 2001 11:01 pm
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Ok...you answered. I see you're stuck in a groove on this one.
Any thoughts Mark or 3T3l1? What about you Dr, Minnis? Do you agree with Seeker?
What's the hang-up here? |
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cydoniaquest
Joined: 12 Aug 2000
Posts: 797
Location: nowhere |
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Wed Jul 11, 2001 11:05 pm
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Oh and you're wrong Seeker....water vapor is every bit a part of the make-up of "air" as oxygen.
[Edited 1 times, lastly by cydoniaquest on 07-11-2001] |
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theseeker
Joined: 25 Jul 2000
Posts: 3403
Location: Damnit...I'm a doctor jim |
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Wed Jul 11, 2001 11:07 pm
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dude...i'll have catch ya' later ...have to go to the market....were just stuck on that one point about air... I don't disagree with what you posted...basically same as what I posted....
btw, keep the poop shoot...the poke would be ok though |
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cydoniaquest
Joined: 12 Aug 2000
Posts: 797
Location: nowhere |
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Wed Jul 11, 2001 11:21 pm
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Seeker, how dare you go to the market right now!....I will not rest until everyone on Earth agrees with me completely and acknowleges the fact that I am always right!!!! Oh yes, This I vow!
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theseeker
Joined: 25 Jul 2000
Posts: 3403
Location: Damnit...I'm a doctor jim |
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Thu Jul 12, 2001 1:27 am
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I will not rest until everyone on Earth agrees with me completely and acknowleges the fact that I am always right!!!!
I know the feeling |
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3T3L1
Joined: 08 Mar 2001
Posts: 1344
Location: Lubbock, Texas |
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Thu Jul 12, 2001 4:16 pm
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Some may remember the original topic of this thread.  If you'd like to pursue the science, come on over to Ms. 3T3's Neighborhood, where we have a discussion ongoing.
http://www.chemtrailcentral.com/ubb/Forum14/HTML/000006.html
[Edited 1 times, lastly by 3T3L1 on 07-12-2001] |
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Lulu
Joined: 22 Dec 2000
Posts: 2501
Location: right here |
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Fri Jan 18, 2002 8:05 pm
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Bumped for the benefit of our new members, and the lurkers who are just itching to jump right in. |
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3T3L1
Joined: 08 Mar 2001
Posts: 1344
Location: Lubbock, Texas |
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Fri Jan 18, 2002 8:44 pm
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Ah, the memories! I've found a site which automatically calculates Relative Humidity from the air temperature and the dew point. Scroll about halfway down the page and look for:
Relative Humidity Calculation using degrees Celsius
Enter in the air temperature (T air) and dew point temperature (T dp)in degrees Celsius (°C) then click on the Calculate RH to compute the relative humidity (RH).
http://www.srh.noaa.gov/bmx/tables/metcal_java.html
[Edited 2 times, lastly by 3T3L1 on 01-18-2002] |
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