The gas coming in isn't cold. The gas left in the filling tank is cold. The
gas coming into the scuba tank isn't expanding all that much...a little
through the lines, and a little as it comes into the lower pressure scuba
tank, but no that much.

mike

"Jose" wrote in message
et...
My point was that I don't understand where the confusion is as to where
the heat comes from in filling a scuba tank. You are cramming a whole
crapload of molecules into a confined space and it makes heat.

Yes, but you are cramming a whole crapload of =cold= molecules into that
space. The heat generated seems like it wouldn't be enough to compensate
for the cold of the inflowing gas.

That gas is cold because it expanded from the other tank, which was under
even higher pressure.

Jose
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