From zippers and bicycles to cranes and fishing rods, simple machines are all around us. This exciting series explores each simple machine, including how each one works, the forces involved, and examples of how they can be used to make our lives easier. Simple Machines is a series of AV2 media enhanced books. A unique book code printed on page 2 unlocks multimedia content. These books come alive with video, audio, weblinks, slide shows, activities, handson experiments, and much more.