Speed distribution
The height of each bar in this distribution graph shows the number of gas molecules with a particular range of speeds in this 2D simulation. As the molecules collide with each other the exact distribution of speeds changes.

Activate the "Accumulate" checkbox to build up an average picture of the speed distribution over a long period of time - you'd see a similar smooth moment-to-moment distribution if there were enough molecules in our simulation.

How is the speed distribution affected by the temperature of the gas?
(Press "Clear graphs" or temporally switch off "Accumulate" after changing the gas temperature, else the graph could take a very long time to show the new distribution.)

Notes:
The green line indicates the average molecular speed, and a yellow bar on the right pops up to show the number of molecules with greater speeds than fit on the graph (when there are any).

links:
Speed distribution curves