This simulator demonstrates how gases of different molecular masses behave when maintained at thermodynamic equilibrium in a chamber. The chamber can be set to allow particles that exceed a certain speed to escape, providing an analogy for the bleeding of a planet's atmosphere into space.
To begin select a gas from the drop-down menu in the Gases panel. You can add up to three gases at a time. Click the start simulation button in the Chamber Properties panel to see the particles in motion. When the simulation is running the sliders and most other options are disabled, so you will need to stop the simulation to make changes.
Note that in this simulation the particles in the chamber are meant to be interpreted as tracer particles — each particle shown represents a great many more particles.
The bar chart at the left side of the Gases panel indicates the absoluate amount of each gas in the chamber. The relative amounts are given as percentages in the gases list. You can drag the bars to adjust their heights, or you can click the reset proportions button to restore all the gases to their full amounts.
One caveat: phase changes are ignored in this simulator. That is, we assume that the particles in the chamber stay in a gaseous state regardless of the temperature or pressure in the chamber.