Simulation of a Simple Gas Pressure Model
Download the CDF file to view the simulation using the free Wolfram CDF player.
This simple model to understand gas pressure considers the gas as a collection of independent molecules bouncing inside a container and counts the frequency of collisions on the container's walls. Pressure, then, equals the force per unit area . Larger numbers of discrete impulses of force can be averaged over an observation time to give an apparently constant pressure.

Contributed by: Jon McLoone (March 2011) 
Open content licensed under CC BY-NC-SA