Parragon Publishing Science Starters: Simple Machines Reference Book for KidsPacked with detailed illustrations and amazing Photographs, Simple Machines covers all six important aspects of machines that have been used by mankind throughout history, with key facts about everything from ramps and pulleys to how they are used in everyday compound machines! With intriguing details and special call outs, this book is a perfect visual guide for young learners who are engineering enthusiasts. Science Starters is a series of reference