wrote:

On Wed, 21 Apr 2004 14:17:14 -0700, Jim Kelley
wrote:

Cecil Moore wrote:

Jim Kelley wrote:

Cecil Moore wrote:

Jim Kelley wrote:
How much does the length change when you tilt it at 45 degrees?

By the factor of the square root of two.

Sounds kinda like one of those mythical cable stretchers. :-)

By Golly, I have been looking for a cable stretcher. A tilted
mercury column will perform that function.

How so?

Pascal's law.

Are you implying that any and every column of mercury must obey Pascal's
law?

73, ac6xg

On Mon, 26 Apr 2004 09:57:59 -0700, Jim Kelley
wrote:

How so?

Pascal's law.

Are you implying that any and every column of mercury must obey Pascal's
law?

Any column of any liquid should. Would you care to cite a
counter example?

If the best counterexample is a 'frozen' mass of Hg, it would be a wee
letdown.



wrote:
On Mon, 26 Apr 2004 09:57:59 -0700, Jim Kelley
wrote:

How so?

Pascal's law.

Are you implying that any and every column of mercury must obey Pascal's
law?


Any column of any liquid should. Would you care to cite a
counter example?

On Mon, 26 Apr 2004 23:02:51 -0400, Bob wrote:

If the best counterexample is a 'frozen' mass of Hg, it would be a wee
letdown.


Hence my specification of "liquid".


wrote:
On Mon, 26 Apr 2004 09:57:59 -0700, Jim Kelley
wrote:

How so?

Pascal's law.

Are you implying that any and every column of mercury must obey Pascal's
law?


Any column of any liquid should. Would you care to cite a
counter example?

Bob wrote:

If the best counterexample is a 'frozen' mass of Hg, it would be a wee
letdown.


That's kind of chilly!! About -37F if my old reference books are still
accurate.

wrote:

On Mon, 26 Apr 2004 09:57:59 -0700, Jim Kelley
wrote:

How so?

Pascal's law.

Are you implying that any and every column of mercury must obey Pascal's
law?

Any column of any liquid should. Would you care to cite a
counter example?

You already cited one. (You can't apply pressure to a confined fluid if
it's sealed in an incompressible container.)

73, ac6xg

On Tue, 27 Apr 2004 10:50:04 -0700, Jim Kelley
wrote:



wrote:

On Mon, 26 Apr 2004 09:57:59 -0700, Jim Kelley
wrote:

How so?

Pascal's law.

Are you implying that any and every column of mercury must obey Pascal's
law?

Any column of any liquid should. Would you care to cite a
counter example?

You already cited one. (You can't apply pressure to a confined fluid if
it's sealed in an incompressible container.)

73, ac6xg

OK, nice specious argument. You can't have read this far in
the thread without understanding the intended parameters. And since
you seem to be referring to the thermometer, pressure could indeed be
applied. In absolute terms, any container can be compressed, however
slightly. In addition, pressure can be applied without compression by
application of heat or of cold, depending on relative coefficients of
thermal expansion.

Old science class demonstration -- completely fill a heavy
pipe, capping both ends, with a substance; heat the pipe with a torch
and it explodes; toss the pipe into a container of dry ice and it
explodes. What is the mystery substance? It turns out to be water at 4
degrees Centigrade.

Finally, I strongly suspect the "column" of mercury in a
thermometer does indeed obey Pascal's law, but it's effect is
overshadowed by the much stronger effects of temperature and
capillarity.

Dave Shrader wrote:
Bob wrote:

If the best counterexample is a 'frozen' mass of Hg, it would be a wee
letdown.


That's kind of chilly!! About -37F if my old reference books are still
accurate.

Rumor has it, despite recent budgetary cutbacks, the freezing points of
Mercury, Water, and even good old Carbon Dioxide will remain unchanged
for the next fiscal year...

;-)



Now, enough humor. Who's tried any experiments yet?
Not entire mercury columns, but just a small quantity at each end of a
collinear or dipole.

On Tue, 27 Apr 2004 14:39:09 -0700, Jim Kelley
wrote:

wrote:
OK, nice specious argument. You can't have read this far in
the thread without understanding the intended parameters.

And I'll assume the same is true for you.

I didn't drift off into the wild blue.


And since
you seem to be referring to the thermometer, pressure could indeed be
applied. In absolute terms, any container can be compressed, however
slightly.

(Speaking of specious)

Just following your lead.


In addition, pressure can be applied without compression by
application of heat or of cold, depending on relative coefficients of
thermal expansion.

Is your claim that the height of the column of liquid in a thermometer
determined by the angle of inclination of the column? You were partially
correct in that the barometer is illustrative of Pascals law.

Thanks for the table scraps.

I believe Pascal's law remains in effect in a thermometer, but
is overshadowed by other factors, including the design you mention,
the details of which I don't know.

Old science class demonstration -- completely fill a heavy
pipe, capping both ends, with a substance; heat the pipe with a torch
and it explodes; toss the pipe into a container of dry ice and it
explodes. What is the mystery substance? It turns out to be water at 4
degrees Centigrade.

True, but not a demonstration of Pascals law.

Nor intended as such. It was in reference to your
incompressibility red herring.


Finally, I strongly suspect the "column" of mercury in a
thermometer does indeed obey Pascal's law, but it's effect is
overshadowed by the much stronger effects of temperature and
capillarity.

True, particularly in light of the fact that a good thermometer is
specifically designed to prevent it from demonstrating Pascals law - or
more to the point, from having its measurement dependent upon its
orientation.

73, ac6xg