Today, one of my former students, who is a physics major at Cornell University, returned to my classroom to be a guest lecturer on quantum mechanics. Her talk was fantastic for several reasons. The level of the lecture was appropriate because, as an alumni, she knew what my students have already learned. She explained concepts really clearly without relying on mathematics well beyond my students, yet still alluded to the mathematical models so students appreciate them. As a physics major crushing her classes and doing really interesting research, she is an inspiration role model for my students. Thanks Cari!