Get to Know Wheels and Axles (Get to Know Simple Machines)
Автор:Paul Challen Год: 2009 Издание: [не указанo] Страниц: 32 ISBN: 0778744884 This book is suitable for ages 7 to 8 years. Read all about wheels and axles and their many uses in this book. Children will be thrilled to learn of their many uses, from doorknobs to the insides of a clock. There are wheels that move, turn, steer, and serve as gears.
