From castles and armor to rockets and robots, an object's design relates directly to its purpose. By understanding the purpose of an object, people can create plans for building the object. This fun series guides readers in planning, building, and improving their own cardboard models of castles, roller coasters, and more. Features include a table of contents, an infographic, a supply list, Think About It critical thinking questions, Making Connections questions, a glossary, and an index. QR codes in the book give readers access to book-specific resources to further their learning. Aligned to Common Core Standards and correlated to state standards. DiscoverRoo is an imprint of Pop!, a division of ABDO.