The newest one in popularity for grade schoolers is Apologia...they have just come out with elementary books (used to be jr and sr high only). They are creation (literal 6/24hr day creationists) based. Also you can order a few of the AiG books about the Ark and Dinosaurs and their site has questions, etc to go with what they've learned in the book...that also would qualify as science. (Weaver has science included --but we will also be eventually using Apologia as well)