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Q & A: compressed gassy baloney

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Most recent answer: 10/25/2012
Q:
http://www.grc.nasa.gov/WWW/K-12/airplane/Animation/frglab2.html
If you freeze mass and pressure in the animation, you get two choices: One of them - the "Effect of Temperature on Volume" - is fine. However, I'd like a second opinion on the "Effect of Volume on Temperature." The caption emphasizes this is an adiabatic process ("blue jar heavily insulated"). How can the gas expand at constant pressure and also rise in temperature - in an adiabatic process? I think such an experiment is impossible to perform. What do you think?
- David Burton (age 52)
Steubenville, OH, USA
A:
You're right that the process is impossible, at least for anything like an ordinary gas. I think this was just a goof. Somebody wrote a caption that was intended to cover only adiabatic processes and somebody else wrote a nice simulation of a broader set of processes. So you can watch a simulated process that's incorrectly captioned.

Mike W.

(published on 10/25/2012)

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