That should make sense to us, because when we talk about a wave function, we're talking about a probability divided by a volume, because we're talking about a probability density.

因为我们说，波函数,是概率，除以体积,因为我们说的是，概率密度，如果我们用它。

麻省理工公开课 - 化学原理课程节选

So, what we can do to actually get a probability instead of a probability density that we're talking about is to take the wave function squared, which we know is probability density, and multiply it by the volume of that very, very thin spherical shell that we're talking about at distance r.

我们能得到一个概率,而不是概率密度的方法,就是取波函数的平方，也就是概率密度，然后把它乘以一个在ｒ处的,非常非常小的,壳层体积。

麻省理工公开课 - 化学原理课程节选