What ar the big differences b/w UK primary and US (SF) elementary schools?

[sanserif]

We've just decided to move to SF where DH is originally from (woohoo!). Our DS would have been due to start Reception in 2013 here in London, so Kindergarten in 2014. I've already toured far too many schools here since we were originally going to move for the school, and while he's not in school yet, I feel like I have an idea of what the schools here are like.

I went to American int'l schools, which are sort of a thing of their own, so not really comparable to 'regular' state schools. What are the big differences I'm likely to encounter, given that I'm going from one urban area to another?

Things I've picked up from the internets seem to be: at least in SF you crazily only get art/music/science if you get into a school with an active, fundraising PTA, parental involvement seems a lot higher, very different start times for different schools, less recess and P.E., foreign language learning taken much more seriously (lots of immersion programs, etc.). What else?

you might want to repost on the living abroad section on here - might get some useful contacts too

It seems to be that the school system in the US varies dramatically from state to state. We have friends in a placement in the states. They seem to think the different start times for the different schools was because of the buses ...? No formal PE in school or school teams, but regular "keep fit" type sessions. Smaller class sizes but less differentiation in lessons. School wouldn't let them in without chicken pox vaccine. One of my friend's DCs was diagnosed in the states with ADD, and the school was very difficult about the parents choosing not to medicate him. The youngest DC learnt to read using whole word system rather than phonics.

Oh - and loads more testing! High schools though have fabulous facilities, much, much bigger than in the UK.

OK thanks. Will also try reposting in Living in America.