Ideal Gas Expansion

This simulation uses Easy Java Simulations (Ejs) to model a two-dimensional ideal gas in a rectangular box. The gas particles are initially confined to the left side of the box with random positions and random velocities (with a Maxwell distribution of speeds). The top view shows an animation of the motion of the particles in the box, while the lower view shows plots of the number of gas particles on each side of the box (red=left, blue=right) as a function of time. The bottom view shows a histogram depicting the number of instances (i.e. time steps) for each various values of the number of particles on the left side.

Controls:

Play/Pause: starts (or stops) the simulation.
Step: advances the simulation by one time step.
Reset: resets simulations with initial parameter values.
Erase: erases the plot and the histogram.
Reverse: reverses the velocity of all particles.
N: sets the number of molecules in the gas (up to 500).
Speed (fps): slider to control the speed of the simulation, in terms of the number of frames displayed per second. Higher values make the simulation run faster.

Units are defined so that Boltzmann's constant, the mass of each particle, the length of the box, and the absolute temperature of the whole gas are all equal to one.