Simulation of diffusion
The 16 particles are initially distributed randomly in a "container" above the surface (the blue line). When you push the start button, random motion starts and the elapsed time is indicated. If a particle:
The number of particles over the top, and in the upper and lower halves of the zone, are determined every 10 cycles (5 sec), and the values in the windows updated. You can stop and start a new simulation, and enter a constant downward drift velocity in the top, left little window.