Waste Wheelers

I’m starting the planning for a book that’s targeted at kids in 5th-6th grade, and could be used as a classroom science supplement/science guide.
So any parents out there who help their kids with science homework, or actual kids what subjects should I try to focus on?

This website has lots of topics and learning resources for science. It is UK based, but I think it will be a good starting place if you are if the USA too.

http://www.compare4kids.co.uk/science.php