Book excerpt: This book presents a program of basic studies dealing with machines and the work they do. The history of machines is presented and the six simple machines identified by scientists and examples of each are illustrated in detail. Additional topics include forces affecting objects, work and power, forms of energy, and compound machines. Each of the twelve teaching units in this book is introduced by a color transparency (print books) or PowerPoint slide (eBooks) that emphasizes the basic concept of the unit and presents questions for discussion. Reproducible student pages provide reinforcement and follow-up activities. The teaching guide offers descriptions of the basic concepts to be presented, background information, suggestions for enrichment activities, and a complete answer key.