Water and Air. Weight.

[Neil Deshpande <deshpand@xxxxxxxxxxxxxxxxxxxxxxxxx>]

Sorry for being so pedantic, but water is LIGHTER than air - Molecular
Weight 18 for the oxygen isotope proteum or O-16.  Air is a mixture of
Nitrogen (28), Carbon Dioxide (44), Oxygen (32) and some other heavier
stuff, and is MUCH heavier than water - in vapour form, of course.  A
weighted average of the components of air would yield an average Mol. Wt. 
of about 29. 

In fact, humid air is lighter than dry air for this reason.  Its lightness
is also the reason it rises to the cooler regions (the higher the altitude
the cooler it is since the atmos is heated by contact with the surface of
the Earth which is heated by the sun) of the atmosphere and then condenses
as rain. 

I once came across and article in Popular Science about a windmill that
used the rising of artificially humidified air to turn a fan.  It was many
years ago, but I think it was just a concept and not an actual machine. 

While talking about weight, it should be noted that it is the fact that 
CFCs weigh such a lot (Cl is 77 At Wt, I think) that it is going to take 
many years for the bits we have released into the atmos. to float up and 
be finished with their destruction.

How the ozone in the ozone layer gets there, etc., is another story and 
can be read at:

http://science.nas.nasa.gov/Services/Education/Resources/TeacherWork/Ozone/Ozone.homepage.html

Sincerely,

Neil Deshpande
86 325
88 325 is
89 325 iC

------------------------------