For an interesting exploration of how even the simple physics of two blocks hitting one another can lead to surprising conclusions, I'd highly recommend this 3Blue1Brown video called "Why do colliding blocks compute pi?": https://www.youtube.com/watch?v=jsYwFizhncE
A lot of times with math I don't think the word "why" should be used. Those blocks computing pi was a good example where they "proved that they compute pi", but not really why. What is the real distinction I'm trying to make here and how to explain it?
