Screws

A Fun Introduction to a Basic Concept of Physics - Screws! Focusing on simple machines and how they help us do work in our daily lives, this fun and informative new series introduces young readers to several basic concepts of physics. We've all seen screws, but how do they work? Why is it easier to screw something into something than to simply push it in? With basic hands-on experiments and clear descriptions, this simple machine is explained.