I am looking for a very hands-on science program for my kiddos for the next year. We have never used a science book before - we have purchased experiment kids, and they have used lots of resource books to supplement. I am looking to stay relatively nature-based for the next year, but I am out of kits! We have done science on a nature hike, tracking expedition, and on a garden adventure. Kids will be around grades 2 and 4. Any ideas? We aren't opposed to either religious or secular science books, as long as they are solid in the subject matter. Thanks for your help!!