KS2 National Curriculum Science - Circuits and Conductors (4F) by CGP Books
This book contains a variety of question types covering everything 8-9 year old pupils need to know about circuits and conductors, following the National Curriculum for science. It's clearly laid out with a topic per page, written in a style that is easy to understand with plenty of space for writing answers. Pull-out answers are included and there's a circuit poster for pupils to colour in.