This is anecdotal but we had a rather particular schedule when I was in our equivalent to high school. We had two classes/subjects per day. So the day was divid

This is anecdotal but we had a rather particular schedule when I was in our equivalent to high school. We had two classes/subjects per day. So the day was divided into a morning block of 2.5 hours, then lunch, and then an afternoon block of 2.5 hours. 20 minutes of break time was included inside each block, and we got some input in how to distribute those 20 minutes. Typically you'd do 2x10, or 1x20 with the 20 being either in the middle or at the end (go home earlier or longer lunch). I found it worked out great for all subjects. You could have a mini lecture first to learn something new, have a break, then have a bunch of time applying what you just learned. Or if we had lectures we had the lecture first then just as much time after for questions. You could watch a documentary and then have a follow-up discussion. We also didn't start classes until 9 AM, because the school knew that teenagers in general aren't at the top of their game in the morning. I really liked that setup.