Re: [Phys-l] App. for Was: Re: T dS versus dQ

[Jack Uretsky <jlu@hep.anl.gov>]

The initial gas temperature and state of ionization could make a 
difference.
			Regards,
				Jack

"Trust me.  I have a lot of experience at this."
		General Custer's unremembered message to his men,
		just before leading them into the Little Big Horn Valley




On Tue, 9 Feb 2010, LaMontagne, Bob wrote:

> With the hope that I won't get shouted down for daring to mention this topic again, may I respond to JM's quoted comment:
>
> But how excruciating must the detail be? If one envisions a cylinder that is absolutely impervious to any energy transfer through its walls, fitted with a piston and containing Nitrogen only, and a stop inside the cylinder that prevents the piston from compressing the gas to less than half its original volume - and then one applies a force with one's hand to push the piston to the stop in 10 seconds - and then repeat with identical apparatus but do the compression in 0.001 seconds, and then let the two pieces of apparatus sit for a while until all waves. etc., dissipate, will there be any difference in their final states - and specifically what? The final volumes are identical, will the final temperatures and pressure be higher?
>
> If this is not a sufficient specification of process and boundary conditions, what else need be specified?
>
> Bob at PC
>
> ________________________________________
> From: phys-l-bounces@carnot.physics.buffalo.edu [phys-l-bounces@carnot.physics.buffalo.edu] On Behalf Of Bernard Cleyet [bernardcleyet@redshift.com]
> Sent: Tuesday, February 09, 2010 6:58 PM
> To: Forum for Physics Educators
> Subject: [Phys-l] App. for   Was:   Re:  T dS versus dQ
>
> Here's the best app. I've seen, but doesn't include the work applied to the piston.
>
>
> http://www.andrews.edu/services/physicsenterprises/products/gas_law.html
>
>
>
>
> I think one may attach a pulley and various lever arm lengths system to do this; along w/ good insulation (removable).
>
>
> bc
>
>
>
> On 2010, Jan 20, , at 11:04, John Mallinckrodt wrote:
>
> > It's interesting to me that the analysis of the rapid versus slow
> > compression of a thermally insulated gas can cause so much confusion
> > and I think the reason has to do with the fact that it can't be
> > easily done by simply talking about work and energy (and it can't be
> > done *quantitatively,* period, without knowing about the process and
> > the boundary conditions in excruciating detail.)  By considering
> > things like the potential energy loss of a heavy piston as it falls
> > or the kinetic energy added to and then delivered by the piston, it
> > can be tempting to suppose incorrectly that the rate of the process
> > is irrelevant to the final state.
>
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