I'm going through another box in the schoolroom and have rediscovered that procrastination leads to less work ;). I'm finding files of things I thought I HAD to do with youngest only for her to outgrow the need and (gasp) learn the necessary skills without my 'must-do' lessons/materials. I found some 'letter of the week' type lessons that she would have enjoyed (indeed she DID enjoy A, B, and part of C) had we done them. But they weren't necessary and she learned her letters/sounds in more natural ways. In my defense, they were mainly a framework using real literature to make sure I was spending some deliberate time with her way back when.
Anyway, in that box I also ran across a page I had printed out from a homeschool forum in which the poster highly recommended the following book for Science: Secrets of the Universe by P. Fleisher. It is now officially on my hurry-up-because-you-need-it-right-now wishlist. There are other volumes which together make up this book if I understand it correctly. This is the complete one (again, if I understand correctly).