I just love the physics of rainbow. Especially when you look into the double and triples. The mathematics behind the light refraction is absolutely beautiful. I had a prof at the U Dub who introduced me to atmospheric phenomenon. Here is a site on the physics and math if you'd care to read it.
http://snrs.unl.edu/amet351/graf/bows.html 
I know this is weird but I find math interesting. When I taught school I could make math fun for 99% of my students... because I was a challenge in school for teachers and administrators as a student, so when I started teaching I decided to be WAY different than the standard run of the mill teacher.
