Science Big Books and Science Student Books Students explore key science concepts through the universal language of the spectacular, real - world photos presented in each big book collection. Each book includes a teacher’s guide with tons of extension activities. Collections are leveled according to the appropriate grade level topics and text content and length. Small book versions available to complement each big book. The Value Set includes 1 big book and a 6-pack of small books. Texts are written with simple sentences and selected vocabulary Level 1 titles.