I’m back, after two weeks of teaching non-experts in a short course covering particle physics, the Higgs field, and the discovery of the Higgs particle. (The last third of the course, on the politics and funding of particle physics and science more broadly, is wisely being taught by a more disinterested party, an economist with some undergraduate physics background.) And I’ve been reminded: One of the great joys (and great secrets) of teaching is that the teacher always learns more than the students do.
At least, this is generally true for a new class that the teacher hasn’t taught before. In many university physics departments, and elsewhere, there is an informal requirement that professors teach a class no more than three years in a row. [Let us ignore for the moment that all of this will be overturned in the coming years by the on-line revolution; we can discuss the possible consequences later.] After the third year, they are expected to switch and teach something else. Now you might think that the benefits of the division of labor would suggest a different approach; after all, shouldn’t each professor perfect a course, become the expert, and teach it year in, year out? This usually doesn’t work (though there are exceptions) because each professor’s interaction with a new course has a natural life cycle.