Ken Bernstein has been a teacher for many years. He blogs at the daily Kos as Teacher Ken.

He writes here about the practical problems of reopening, such as social distancing in classrooms, hallways, cafeterias, and on buses.

This is what he writes about classrooms:

CLASSROOMS — It is impossible in most schools to have 6 foot between students. Last year I had up to 30 seniors in a room at a time, with a social distance rarely even 2 feet between them. To get to 6 feet I would have to limit the number of students to around 10-12. To even get to a 3 foot distance in between would probably require a doubling of the number of classrooms, even maximizing use (teachers floating into rooms where a teacher has a period off). Very few buildings have that kind of excess space. And even if you could get to 6 foot distance, how do students maintain that coming in and going out of the room without creating problems in the hallways?