Screws

From spiral staircases to nuts and bolts, people use screws in many different ways. Screws can fasten objects together or help people move around. Learn all about these simple machines and how they work in Screws, an AV² media enhanced book. This is an AV² media enhanced book. A unique book code printed on page 2 unlocks multimedia content. This book comes alive with video, audio, weblinks, slide shows, activities, hands-on experiments, and much more.