The Statistical and Thermal Physics (STP) JavaScript Chaos program is a ready-to-run computer model for the teaching of statistical and thermal physics. In this program we initialize 11 particles moving with the same velocity such that the net force on each particle is zero. The particles interact through a Lennard-Jones potential. Perturb the system very slightly and see what happens. The velocities can also be reversed to see to what extent the system is reversible.

The goal of this simulation is to explore how the smallest perturbation changes a special initial state of the system to one we would expect at thermal equilibrium. The idea of chaos or sensitivity to initial conditions is needed to understand why this happens, and to help explain irreversibility.


The STP Chaos program shown here was converted from Java to JavaScript by Wolfgang Christian and Robert Hanson (St. Olaf College) using the SwingJS system developed at St. Olaf College.