I can find 2.25 clearly accountable hours without losing any academic content: - Lunch and recess (45-60 minutes). - Passing periods (27-28 minutes). - Lifes

I can find 2.25 clearly accountable hours without losing any academic content: - Lunch and recess (45-60 minutes). - Passing periods (27-28 minutes). - Lifestyle activities: art, health, gym, music, etc. (45 minutes). Now some fluffier ones: - Suppose, like a typical Coursera user, I can understand the content at 1.2x classroom speed. There's 60 minutes. - The door-to-door transition period is four minutes. But settling in, packing up, pleasantries, and administrivia probably put the lecture-content-to-lecture-content time at closer to 10 minutes. So there's another 42 minutes. There. I just found 4 hours with losing a drop of college-relevant material.