"basskisser" wrote in message
om...
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??

There are several properties of gasses that can easily be demonstrated
using liquid nitrogen. These properties include phase changes (gas to
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
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
breath filled balloon or a balloon filled with a gas such as ethane
(95o C difference between freezing and boiling points).

Rick and I just worked this out for water. In a race car tire that reaches
225 F to 250 F during normal operation, there *is* a phase change in water,
from liquid to vapor. The newly introduced water vapor can add a significant
component to the partial pressure composition of the tire. The only thing
left here is to determine how much liquid water might be found inside a tire
in different settings.

Now in the temperature range of interest, operating tire temperatures, are
any of the materials you mention (Nitrogen, Argon, Oxygen) undergoing any
phase changes?
If not, do they show any appreciable deviation from the ideal gas properties
in the temperature range of interest?

If not, suck it up and move on.

Mark Browne
P. S. You would not be doing a Jax here, would you? That is, trying to
define the problem in such a narrow way as to give yourself a little wiggle
room. This is not necessarily a bad thing - some us miss toying with Jax!