They take an atom of lead, accelerate it and have it collide with an atom of nickel.

他们选取一个铅原子，将其加速,让它与镍的原子碰撞。

麻省理工公开课 - 固态化学导论课程节选

The molar volume is being changed a little bit trying to make things collide with each other, they can't occupy the same volume.

摩尔体积发生了很小的改变,如果你试图使气体分子间相互碰撞，他们不能占据同一个位置。

麻省理工公开课 - 热力学与动力学课程节选