Here are a couple of other ideas, maybe?
Caveman Chemistry: Hands-on Projects in Chemical Technology (
www.cavemanchemistry.com )
There's a series of books (from Chicago Review Press) about middle-school level that look quite interesting--we've done a certain amount with the astronomy book, but have only really had a cursory look at the other ones:
Mario Salvadori, The Art of Construction: Projects and Principles for Beginning Engineers and Architects
Matthys Levy and Mario Salvadori, Earthquakes, Volcanoes, and Tsunamis: Projects and Principles for Beginning Geologists
Matthys Levy and Richard Panchyk, Engineering the City: How Infrastructure Works
Richard Moeschl, Exploring the Sky: Projects for Beginning Astronomers
and there's a biology one, too, whose name I can't seem to turn up at the moment....I'll hunt around my bookmarks and get back to you!
peace
minnie