I find that if I teach a course in the afternoon I have previously taught in the morning, I am left at the end of the fifty minutes with a fair amount of uncovered lecture material—maybe as much as ten to twenty percent of what I thought I’d do.1 Which suggests of course that I talk markedly more slowly in the pm than in the am. Or maybe I dilate more expansively on a given point.
Students who believe I talk too fast or cover too much too quickly may wish to consider the availability of slower, afternoon Eric.
I bet there are other odd factors that determine the relative quality of one’s teaching—how much sleep one gets, how much coffee2 one drinks, etc.
1Based on an observed sample of two instances of am/pm shifting.
2There are of course other beverages that have marked effects; I remember one person who argued white wine doesn’t count, so you can drink it in the morning, and another who would place a pint on the windowsill in the lecture hall, for ready access… these are obviously not stories of our time and place.