If I place my container of gas on the table here, and I come back an hour later, the pressure needs to be the same when I come back Otherwise it's not equilibrium.

如果我把装气体的容器放在桌子上，一小时以后我再回来时,气体的压强应该是不变的,否则它就不是平衡的。

麻省理工公开课 - 热力学与动力学课程节选

It's reversible, that means that p external, equals p. I'm doing it very slowly so that I'm always in equilibrium between the external pressure and the internal pressure so I can go back and forth.

我都可以不损失能量，而把过程逆向进行,整个过程中的,每一步都保持平衡,现在我们来分别。

麻省理工公开课 - 热力学与动力学课程节选

If p2, the pressure in p2, is less than the pressure in p1, is the gas going to want to go from p2 to p1 and the whole thing reverse back?

比p1中的压强小,在整个逆向过程中气体,会从p2到p1中去吗？

麻省理工公开课 - 热力学与动力学课程节选