You need a functional form that connects the value at one state of matter, the freezing point of water to another phase change, the boiling point of water.

你需要一个函数形式来,连接物质某个态对应的温度值，如水的冰点，和另一个相变,如水的沸点。

麻省理工公开课 - 热力学与动力学课程节选

A linear interpolation between the two, and then some numbers associated with them, 2 7-1/2 and 22-1/2. Why does he choose 7-1/2 as the freezing point of water?

两者之间做线性插值，一些数值随之标定，7。5和22。5，为什么他选择了7。5作为2,水的冰点呢？

麻省理工公开课 - 热力学与动力学课程节选

Water boils at different temperatures, depending on what the atmospheric pressure is; same thing for the freezing point.

丹佛和波士顿水的沸点，就不一样;,在不同的大气压下。

麻省理工公开课 - 热力学与动力学课程节选

And Celsius first used the boiling point of water, and called that 100 degrees Celsius, and the freezing point of water and called that zero degrees Celsius.

定义一些参考点，例如摄氏温标定义水的沸点，是100摄氏度,冰点是0摄氏度。

麻省理工公开课 - 热力学与动力学课程节选