So when I expand this gas adiabatically and it cools down, why do you think it might cool down?

现在我们知道了气体绝热膨胀时,温度会下载，为什么会降温？

麻省理工公开课 - 热力学与动力学课程节选

Well the power points will be available before, say for this lecture it will be before so that you can use them in class.

幻灯片其实课前就能下载，这样你上课时就能用到。

哈佛公开课 - 幸福课课程节选