How does bubbles and isolating in schools work?

[ssd]

My kids are older and I've no friends with kids still in schools

I've read a lot here but dont understand it

Can anyone explain

What i mean is ,if they are in a bubble and someone get it, do they all isolate? How big are the bubbles?

It seems to vary how each school sets up bubbles. Some it's by class, others it's year group. Once the secondary school kids start mixing forms for different subjects / sets it gets a lot harder and the bubbles can be huge.

So in a secondary, if the bubble is big, the whole bubble has to isolate if someone gets it?

At my daughter primary a bubble is a year group , but they are meant to keep track of when the classes have mixed indoors. If a child tests positive the whole class isolates and any child in the other class who has spent more than 15 mins with that child (in say a maths group for example).

At the high school, its also a year group bubble but they only send home children who have sat next to or in front of the child home in each lesson (done by seating plan). They 'sometimes' ask the child who they spent significant time with at lunch or breaks but this is pretty un reliable.

@ssd

So in a secondary, if the bubble is big, the whole bubble has to isolate if someone gets it?

This was the original plan in September but they quickly refined it to smaller groups based on seating plans in our school.

To qualify, the year group is a bubble but they only send home parts of the bubble not the whole bubble.

Its very non scientific given they all go mix at the bus stop, in the shop after school and on the bus etc