There's the hard sphere. It wants to collide against the wall to create a force on the wall, and I have a couple of the hard spheres that are nearby, right, and in the absence of any interactions, I get a certain pressure.

给墙一个作用力,现在它的附近，还有许多小球,没有相互作用时,它将直接冲向这面墙。

麻省理工公开课 - 热力学与动力学课程节选

The molar volume is being changed a little bit trying to make things collide with each other, they can't occupy the same volume.

摩尔体积发生了很小的改变,如果你试图使气体分子间相互碰撞，他们不能占据同一个位置。

麻省理工公开课 - 热力学与动力学课程节选