That seems a sensible solution to the problem. Although a potential nightmare for childcare for parents returning from furlough etc.
It is a childcare nightmare here with the kids only directly attending school for 50% of the time. Ironically as a teacher, I'm classed as an emergency worker and my kids are eligible for emergency childcare, so they go to school on other days too and are supervised.
But in secondary schools it is impossible to stay in one class. Chemistry lessons need labs, as does Physics and IT / Computer type classes. Even languages often need equipment that is not available in every class. This needs rotation of classes.
This is what is planned for English secondary schools in September. Pupils will be in year group bubbles with all subjects except those requiring a specialist room being taught in the same classroom and staggered break times. At my school, pupils will still come to science labs for their science lessons but no practical will be allowed - only teacher demonstration. This will require some considerable rewriting of schemes of work over the summer as our syllabus at key stage 3 is highly practical. Pupils will have exercise books but they will not be collected by the teacher for marking - all work requiring marking will be submitted electronically. We will also not be able to lend equipment so if a child forgets it’s pen, it’s tough.
As Julia wrote above, secondary schools here in Germany are also able to remain static. Science lessons are barred from conducting experiments at the moment, so the teachers don't need to be teaching in specialist labs. As for computers, my wife's school has no computers at all and in my school, all the kids have their own laptops that they bring in, so it is possible for the kids to remain in one room all day. It's true that it won't work for every school, but it's all about reducing the risk where we can.
Another measure is the submission of seating plans for everyclassroom. So every single lesson we write down where every pupil was sat and the teacher in the room. We also strictly control where the pupils can play on any given day, this is then collated and sent to the local health authority every day, so if we do record an instance of Covid 19, then we can immediately trace the other pupils and adults who may have interacted with them.
Another interesting thing about all of this is the legislation that's been passed at county level, our school is liable for some pretty hefty fines if their found to be in breach of the rules and the county have been doing spot checks on schools to check for compliance.
