The aim of this community give you the support you need to excel at GCSE Science. It focuses on the GCSE syllabus, but it would also be great for key stage 3 as there is so much crossover.
Ask any science questions and I'll answer as soon as possible. Members get a access to a website with interactive activities. There are videos, revision notes and tips on exam technique.
And it's free at the moment, so there's nothing to lose.