What Do Pulleys and Gears Do? (What do... do?)
By David Glover.
Description
Looking at pulleys and gears, this is one of of a series which aims to develop children's knowledge of the basic principles of design and technology. Each book introduces a particular principle and explores how it is used in different gadgets and machines. - from Amzon
ISBN(s)
0431062730, 9780431062730
