I'm looking for suggestions for a series of presentations I have to give to my fellow physics seniors. The idea is to try to find something interesting and teach the rest of the class about something they wouldn't normally see, but on the other hand it's only a 1 hour course, so it can't require an extravagant amount of work. There is a 10 minute presentation to the class, which should ideally be accompanied by a handout with some more detailed mathematics. I chose the Standard Model as my theme for the semester, and my first two presentations to the class were about basic definitions (leptons, bosons, etc.) and the LHC, and an attempt to explain symmetry breaking, which I wasn't very clear on myself. Now I find myself out of ideas. I feel like there should be a simpler, elegant derivation in QED or something that I can teach myself and present with confidence. If the presentation is 10 minutes of me deriving said equation on the board, that's fine too. Any ideas?