Physics Tidbits

Reduction in entropy via Jezzball

I was studying the ideal gas for my 112 midterm, and found the explanations in Kittel the most vivid that I've encountered, which is surprising since at first glance it seems like the book will be of the driest kind.
     It made me think of Jezzball, a game I used to play. In an irreversible expansion, a partition is removed, but the temperature (and energy since U=3/2Nτ) of the classical ideal gas does not change, and no work is done on or by the gas. Why? Well, you don't change the particles' velocities, as you would by pushing on the particles in compressing with a piston.
   Well, in Jezzball you are doing something similar, but instead you are doing no work, keeping the temperature the same, but making the volume smaller. This would lower the entropy without paying for it, how? Well, this is an alternate take on Maxwell's Demon, which tells us that the opposite of a free expansion cannot occur, which is why we call it an "irreversible" expansion.

__________________________________________________________________________________________

Society and Economics as an Ideal Gas
For ages people have looked for analogies between classical thermodynamics and economics. Here is one paper that treats the topic in mathematical rigor.

__________________________________________________________________________________________

I watched this video of Richard Feynman last night and it filled me with joy.
I think everyone has wondered at one point, "why do magnets repel," and although his initial response to the interviewer,"because there's a magnetic force that makes them repel" at first seems terse, his substantiation justifies the response beautifully.
The answer to a student of physics does have more layers of depth, but even our best understanding today reaches a point where there are unanswered why's.




__________________________________________________________________________________________

I was thinking about how the moment of a spinning top precesses around a vector antiparallel to the gravitational field, whereas a magnetic moment precesses around a vector parallel to the magnetic field...how can we resolve this discrepancy...should we change our convention of the direction of magnetic or gravitational field?