Sound Reading Objectives What Do You Hear? What Is Sound? Loud and Soft High and Low Sounds Around You Light Reading Objectives Light for Life Sources of Light Bouncing and Bending Light Making Shadows Light and Color Glass Reading Objectives Amazing Glass The History of Glass Making Glass Today Glassblowing Recycling Glass Different Kinds of Glass Simple Machines Reading Objectives Work Machines and Work The Inclined Plane The Wedge The Screw The Lever The Wheel and Axle The Pulley Review Activities Think and Discuss Multiple-Choice Test Index