What is sound?

In the following chapters of this book, we will learn how to use plugins that manipulate sound. But what exactly is sound? When we talk about sound design, what exactly are we designing?

Sound is a form of energy like electricity and light. Sound is made when molecules vibrate and move in a wave pattern, which we call sound waves. Air is able to support many sound waves simultaneously. When you clap your hands, your clapping causes energy to move outward into the air. The air molecules vibrate, bump into neighboring molecules, and transfer energy, causing them to vibrate. This energy gets dispersed outward from the source, around the room, and continues until the molecules run out of energy. The energy gets weaker as it gets distributed over a wider area. This is why there's no sound in outer space. There are no air molecules vibrating to support sound waves.

Molecules don't move around the room with sound though; rather, the energy is transferred between...