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Re: [Phys-l] T dS versus dQ

This method is not, I think, very practical, i.e. expensive, very time consuming, etc.

Could one substitute a heating element instead of the speaker? Very easy to measure the E in.

Could the commercial app. at least two members have be insulated and the heating element and a T added inexpensively?

bc intrigued and will to spend some of his very hard earned retirement to purchase that or similar app. for modification, IF reasonably assured of success.

p.s. one prob. students will be suspicious of using two different methods of adding energy?

On 2010, Jan 17, , at 20:11, John Denker wrote:

There is a piston
with weights arranged so that there is initially mechanical
as well as thermal equilibrium. The plan is to add a
specified amount of energy.

In subcase 3a, we wiggle the piston at high frequency by
means of a sound transducer. This adds a little bit of
energy to the system. Sooner or later, presumably rather
soon, all of the sound is dissipated. The sound energy
causes the gas to expand. The gas expands at constant
pressure as determined by the weights. In so doing, it
does some work against the weights. This macroscopic
mechanical energy-output is strictly less than the sonic
energy-input. We keep doing this, little by little, until
the total delta E (sound in minus macroscopic mechanical
work out) is equal to the specified delta E required by
the statement of the problem.