While presenting only a minimum of information on the topics, these simple books provide younger readers with basic introductions to some of the physical principals that shape our world. Easy activities give readers a hands-on understanding of the concepts. Bright color photos of both boys and girls engaged in activities and an eye-catching design make these appealing offerings. Glos., ind. (c) Copyright 2010. The Horn Book, Inc., a wholly owned subsidiary of Media Source, Inc. No redistribution permitted.