"Gene Kearns" wrote in message
...
On Tue, 13 Jun 2006 12:52:32 -0400, RCE penned the following well
considered thoughts to the readers of rec.boats:

Water vapor is the same. The rest of the gases (particularly nitrogen,
which makes up most of the atmosphere) suck up the water vapor and we call
it humidity. (water vapor also won't compress)

RCE

Eisboch,

"the gases suck up the water vapor"

"water vapor also won't compress"

That is the weirdest science I have ever read in my entire life!



Heh. I suppose the "sucks up" is a stupid way to put it. However, a dry gas
will "absorb" water vapor. In the vacuum industry we routinely backfill a
vacuum chamber with dry nitrogen in order to absorb residual water vapor
from internal components of the chamber. Residual water vapor clinging to
components and the stainless steel chamber walls is the bane of vacuum
chamber processes and can create variations in the results of thin film
deposition. The water vapor adheres due to the "Vanderwalls effect" and
often heat or another form of energy (UV radiation) is required to release
water vapor molecules to be pumped by the chamber vacuum pump systems. Dry
nitrogen is often used to at least partially vent a chamber to minimize the
amount of water vapor to the chamber walls and internals.

Ever try to buy a bottle of compressed "water vapor"? If you can find it,
I'll buy it.

But, I agree with you. After 30 years in the high vacuum systems business,
it *is* a weird science, but one that routinely deals with vapor pressures
of solids, liquids and .... water vapor.

RCE (Eisboch)

www.eisboch.com