At my school, we have more than two hours between the end of our recess and lunch. So having a hundred minute period can allow the teacher to focus on one topic and still get to the other topics because we have the time. Fifty minutes is not long enough for one period.
We could have an 100 minute period , but our mind should be focused.Right?
For example, i love maths . I used to workout problems 2 -3 hrs solidly without having a break.
But i hate social studies, i used to study the book for maximum of 1/2 hr only and would have break for 10 minutes ,then will continue.
Our perplex mind will be focused on a topic what it likes.
It deteriorates other things which it dislikes.
So having an 100 minute period will be helpful few subjects only not for all .