Now, I want to mention one more thing. Now, recall that kinetic energy is equal to one half mass times velocity squared. So suppose I have two molecules, one heavy molecule and one light molecule with the same kinetic energy. Well, according to this formula, if the kinetic energies are the same, then the higher or the heavier molecule will have a lower velocity, while the lighter molecule will have a higher velocity. We could also talk about the average velocities of the molecules, and that's simply average of all the molecules found in our system. So, on average, if you pull out a molecule from our system, it will have an average speed.