Physics books anyone?

     So I started writing a children's introduction to physics. The target audience is young boys, 9-13, with a scientific bent. Unfortunately physics has been a hard topic to cover. While I have no problem studying specific laws/concepts/history. Every time I get started on the basics, the very general principles, and of course the major problem of how everything fits together- I start to feel like this guy:



   And I don't think I'm going anywhere. Does anyone have any physics books suggestions? Be it full length textbooks or interesting picture books you've run into, I'd love to hear what you've got!