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On 31 Oct 2003 04:52:56 -0800, (basskisser) wrote:

Rick wrote in message link.net...
Mark Browne wrote:

Now you have my curiosity!

I understand all gases to expand about 1/270 per degree C at room
temperature.

Please explain how now nitrogen and oxygen differ?

This should be a good one ... but don't hold your breath waiting for a
response. I am just amazed that he doesn't just look up the gas laws and
see for himself. Bizarre.

Bass posted this and I haven't heard from him since I answered him, so
if you attempt to explain it to him maybe he will finally just go away.

You apparently don't know squat about the Laws of Gases.
Now, Im again telling you that the ONLY reason is that
the pressure to temperature ratio is more linear.
Do you refute that? If so, do tell why. Now, I suspect that
you don't UNDERSTAND my answer, and that is the reason that
you don't think it's correct. So, allow me to explain.
The nitrogen doesn't expand as much as air, for a given
temperature change.

The level of scientific illiteracy in this country is frightening when
you see it defended so hotly by those with the smallest armory.

Rick

Yes, I agree, the level of scientific illiteracy is frightening. Here
you go, and Shelikoff, can you read this and comment??

Sure.

There are several properties of gasses that can easily be demonstrated
using liquid nitrogen. These properties include phase changes (gas to

First problem is that you're using *liquid* nitrogen to demonstrate a
property of nitrogen gas. It's properties as a liquid and during the
phase change to gas is absolutely and completely irrevelant to it's
pressure/temperature/volume relationship in it's gasous state.

And since we're talking about air vs. nitrogen in a tire, they are both
gasses and not liquids. Even the water *vapor* in the air is a gas and
has the same pressure/temperature/volume relationship as nitrogen, as
long as the vapor doesn't condense. And if you are at all careful about
limiting the amount of water in your compressed air, it shouldn't
condense.

liquid, liquid to gas, and visa versa), and the temperature dependence
of volume. If you have a volunteer blow up a clear balloon, you can
show how a gas (oxygen) can go from gas to liquid. Oxygen has a
boiling point of -180o C, so when the balloon containing oxygen from
someone's breath is submerged in the liquid nitrogen the oxygen is
cooled to below its boiling point and it begins to condense. There is
usually some water vapor present in this balloon also- under good
conditions, the water vapor will condense to liquid and then freeze,
thus going through two phase changes. You can also discuss the
kinetics involved in the balloons expanding when they are removed from
the liquid nitrogen and begin to return to room temperature. Notice
how the lighter gasses do not constrict as much since the boiling
points of hydrogen and helium are both lower than that of nitrogen.
You may also notice though that they will also expand a bit faster
than the heavier gasses. The differences in the expansion rate becomes

No, you won't notice that hydrongen and helium will expand a bit faster
than the heavier gasses. Because they don't.

even more obvious if argon is available. Argon has a very small
difference between the freezing point and boiling point (4o C) thus an
argon filled balloon will expand very rapidly. Compare this to a

Neither will Argon. As long as you keep the temperature above it's
boiling point, it will expand just as fast as any other gas as you raise
the temperature further.

breath filled balloon or a balloon filled with a gas such as ethane
(95o C difference between freezing and boiling points).

You're understanding of physics is abysmal if you think that because
different substances have different PVT relationships during a phase
change means they will not follow the gas laws, which say they will have
the same PVT relationship as a gas.

The fact that you're trying to demonstrate that gasses do not follow the
gas laws (which is a necessity if you want to claim that a racing tire
filled with nitrogen has a more linear temperature pressure curve than
one filled with air) by using a phase change argument is specious at
best.

Steve