00:01
So we're taking a look at an ice cube.
00:03
And we'd like to know, are there any conditions such that an ice cube can melt reversibly? and there is one condition at which you can melt reversibly.
00:16
And when you want to think about a reversible process, you should really be thinking equilibrium.
00:23
And so if we're thinking about equilibrium of melting of an ice cube, well, what is really going on there, right? we have a combination of melting and freezing.
00:39
And what conditions could we have where if we just add a little bit of heat, we can melt, but if we remove some heat, we can freeze.
00:48
And at normal conditions, at one atmosphere of pressure, we can do that at zero degrees celsius.
00:59
At zero degrees celsius, if we add heat, we will melt...