In elementary schools, students used to have lots of time to play.  They are, after all, just children.

In MY elementary school that I attended as a child, the day started at 8:30 and ended at 3:30.  We had an hour for physical education every day.  We had recess for thirty minutes in the morning and thirty minutes in the afternoon. We could go across the street to the "candy stores," if we showed the teacher monitoring the corner our nickel! We had an hour off for lunch.  Sometimes I would walk home, eat lunch and walk back to school.  (I walked there in the morning and walked home in the afternoon.)  I lived at least twelve long blocks from school. It was good exercise. (But it wasn't uphill in the snow!)

I'm always amused about the current situation in our schools where they give the students precious little time to just play.  And then they wonder why they misbehave!  Children are children in spite of "education reform."  Any parent knows that if their children wear themselves out playing outside for as long as possible, they will go to sleep ever so much faster and stay asleep ever so much longer--a situation which is better for the children AND their parents!

It's not like they are doing anything else that is more consequential to their educations instead.  If one monitors the academic activity spent during an elementary school day, one will find that it's about 45 minutes on task!  And yes, that's a total amount.

Pretty much, time periods have been changed, not to accommodate subject matter or students or religious holidays of those students, or for any other worthwhile reason, but instead they have been changed to satisfy some adult's agenda-- which is kind of sad, I think.