Hi LadybugMom, I'm another with a 5yo science buff. You've had some good suggestions already, but my addition would be to suggest one of the many books of science experiments for kids - I can't find a link for the specific one we have, maybe it's out of print aleady, but there are various ones in the same style. You want clear pictures, instructions and other text, and correct science of course (I've seen the occasional howler in kids' science books, but my impression is that they're fairly rare). Actually doing the experiments is great for developing scientific thinking ("what might happen? why? let's see..."); I think it gives something that just reading about science doesn't.
