There's a meteor just making its way across the universe and there's a planet in the vicinity (maybe Earth). It either wipes out all life or it misses the planet. Can we know our doom beforehand? This class will answer that question, and it will help you answer many more. Collision Theory is the physicist's tool for answering: will these two things interact? It also lays down the groundwork for the scattering experiment - a powerful tool for investigating the structure of atomic and subatomic objects. If you've heard of Rutherford, then you know he discovered the atomic nucleus, and he did it with Collision Theory. We will cover the basics of the theory by introducing the concepts of the cross-section and impact parameter, and then I'll show you some interesting applications. In particular, will this neutron cause that Uranium atom to split? Will that meteor wipe out life as we know it?