I am going to be teaching an introductory university class on E&M and Modern Physics (from Coulomb's Law through Maxwell's Equations and optics, followed by a brief mention of quantum and relativity) to students in the 'life-sciences' (which, according to our department, pretty much includes any scientist who isn't a physicist or an engineer). Previously, this class has been taught more as a watered-down version of the more advanced class for physics majors. I'd like to be able to engage the students more, so I am looking for interesting (and maybe even fun) examples of life processes (could be from biology, neuroscience, chemistry, geology, etc.) that can be well explained, perhaps up to an approximation, by the physics of charges, magnets, and photons.
I'm already planning to do something with action potentials, MRI, the eye, and X-rays, but I'd like to see if there are other, less common examples. And since this is an intro class, and since I myself have very little prior knowledge of biology, etc. I am most interested in examples that depend only minimally on prior knowledge of either field.
I appreciate any input the community can provide.