part II Statistical and Thermal Physics

Teaching Resources by David J.C. MacKay

Some notes on Statistical physics

  • About Free Energy and Availability (postscript)
  • About Liouville's theorem, the Boltzmann distribution, and the isothermal atmosphere
  • About Variational Free Energy
  • Computer demos

    Bonk demo - matlab (gzipped tar file)
    Simulates particles of various masses in a one-dimensional box; the number of particles is small, about 20; allows one to see approach to thermal equilibrium, fluctuations of pistons, adiabatic behaviour of gas, effective spring constant of gas.
    (*) Bosons, Fermions, and Classical particles (tcl)
    Shows a bunch of energy levels and states of a multi-particle system and their occupancies; you can vary the energies and the temperature. Shows fermi distribution nicely and makes clear the difference between bosons and fermions. Demystifies bosons, in my opinion.

    The tcl programs and other links marked (*) can be run directly in netscape if you have got the tcl/tk plugin. You can also run the tcl programs in the normal way if you have a linux machine with X windows and tcl and you download the tcl files then execute them (this is preferable to the netscape approach, I think). The other programs can be used by people on unix systems who have the relevant software (perl, gnuplot, octave.)


    David MacKay / mackay@mrao.cam.ac.uk - home page.