@Charred - Billiards is one thing, but small particles are another. Light scattering by small particles would seem to result in a somewhat random occurrence, you would think at first.
But in my college physics course we discovered that they had their own set of formulas just as you did for large scale objects.
It has applications in a variety of industries. I remember watching this big budget Hollywood animated movie once where most of the action took place in the ocean.
The animated spectral colors and refraction from the light were incredibly realistic, no doubt because they followed the same formulas as used for real life light scattering.