A bigger issue would be that a course isn't presented to a small group of kids who need to be engaged ("shaken by the shoulder" as the author says), it's for t

A bigger issue would be that a course isn't presented to a small group of kids who need to be engaged ("shaken by the shoulder" as the author says), it's for the whole class, including: - kids who're already engaged, though aren't studying on their own and need some bare explainations - kids who don't want to be engaged and won't be anyway - kids who could be engaged depending on some other factor that no other kid cares about Teaching to a class of 30+ kids means you can't take any extreme bet on what will work as a teaching method, and going for the most energy efficient way is a good practice in general.