Screws

The first two chapters in each volume--an introduction to the scientific concept of "work" and the simple machines that make it easier--are somewhat similar and sometimes share the same illustrations. The books describe various types of machines and explain the scientific principles that make them function. Some simple activities are demonstrated in the pedestrian text and accompanying color photographs. Glos., ind. [Review covers these Early Bird Physics titles: [cf2]Inclined Planes and Wedges, Levers, Pulleys, Screws, Wheels and Axles, Work[cf1].] (c) Copyright 2010. The Horn Book, Inc., a wholly owned subsidiary of Media Source, Inc. No redistribution permitted.