Hi nicknamerunout:
Tricky question. Like Madmog we were told roughly 30 minutes per subject per week - working out between 30 minutes - 1 hour per day on homework. School also encourages additional reading for pleasure on top of this.
However - in practice homework time estimates aren't really happening. This is partly because a lot of the homework is meant to be finishing things started in class. So we seem to be in a situation where the brighter students whizz through the work in class and have very little to do at home and those struggling, seem to have lots of homework.
Now whether this is the school 'leveling the playing field' as it were - or just coincidence I'm not clear on - and basically won't be privy to that information from the school.
As a parent I'm a little [skeptical] that the school is really 'planning' ability appropriate homework when in fact 9 times out of 10 all pupils are assigned the same work. I think this is where the school is rather letting both ends of the spectrum down - as friends with children who are struggling complain the homework is too hard/ takes too long and people like me with a strong student (in maths at least) have next to no homework - and they're getting practically everything correct on the work they whizz through in class.
I'm so battle worn - I just ask what more could we do. If we get suggestions (and sometimes we do) we do that - if not I ask teacher friends here or in the US for ideas.
Our solution has been to do more on our own. Especially in Maths - DD1's favourite subject and sciences. Fortunately there's a lot out there on-line that's accessible:
Maths:
Corbett Maths 5 a-day: corbettmaths.com/5-a-day/ - problems are for GCSE revision at 3 difficulty levels. Right now DD1 (who is in Y7) is accessing Numeracy/ Foundation problems. We look at higher - but often have no clue. The answers are provided & worked - so that helps when she does get something wrong.
NRICH Maths puzzles: DD1's teacher suggested she do this. You can send in your answers and your name & school appears - which DD1 really loves - so she is happy to do more.
School subscribes to on-line maths tutorial: My Maths - DD1 plays games and does Level 6 maths work on her own - viewing lesson & doing homework. Teacher can see she does it - but it doesn't interfere with class assignments.
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Science:
MIT K-12 videos: corbettmaths.com/5-a-day/
Royal institution Christmas Lectures: www.rigb.org/christmas-lectures - & wonderful my favourite element series - there isn't a link but if you type my favourite element into their search box you can get there.
Periodic table of videos from wonderful team at University of Nottingham: www.periodicvideos.com/
Smarter Every Day - videos of odd/ interesting science experiments - from Alabama USA - kids adore it: www.youtube.com/user/destinws2 - a lot of this is simple observational physics - it's a bit kooky and that's probably it's appeal.
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we also tend to encourages DDs to watch documentaries on topics of interest to them. BBC is great for this.
As ever BBC bitesize can give you further information/ clips/ sometimes games for more practice in subjects as well.
HTH