What is wind? What is it made of? What can it do? In this lesson, students explore ways to change the speed and direction of a Ping-Pong ball using a handheld air pump to simulate wind. Simple experiments help them understand that air has weight and moving air applies a force to objects. Students investigate how wind strength, opposing wind force, and weight affect the motion of a sailboat. This sample chapter also includes the Table of Contents, Preface, About the Picture-Perfect Science Program, Lessons by Grade, and Index.