 So in this video we're looking at our ideal gases again, but we're going to look at the case where the volume stays constant. Now typically in this system, if you keep the volume constant, the way you induce a change in the gas is to add some heat or remove some heat from the system. And then we're going to see how the temperature and the pressure respond to those changes. So first I'm adding some heat, and you're going to see that the temperature increases, but the pressure also increases. And if I remove some heat, the temperature drops and the pressure drops. And we can use our ratio equations, which I talk about in a different video, to help us actually come up with the relationships between those things.