For thousands of years, six simple machines have helped people do amazing things. Each title in this informative series introduces young readers to one simple machine, describing how it works, how it helps people do jobs, and how it is used for fun. This informative book introduces young readers to pulleys, describing how they work, how they help people do jobs, and how they are used for fun. The book also includes a "That's Amazing!" special feature, several "Did You Know?" facts, a table of contents, quiz questions, a glossary, additional resources, and an index. AGES: 6 to 8
