Written by Travis M. Moore
Last edited Sep-2019

The Physical Properties of Sound

A formal definition of acoustics is: "a science that deals with the production, control, transmission, reception, and effects of sound."1 As you can see, there is a lot to consider when studying sound!

In order to get a feel for how all of these principles come into play, it's helpful to ask: "What exactly is sound?" How would you define the concept of sound to another person? You might say something like sound is what a person hears, but acoustics is not concerned with what a person perceives (that science is called psychoacoustics), but rather the sound signal itself. Once we begin to consider the actual process of how human beings perceive sound, we must begin examining sound as a physical property.

Once we think about sound as having a physical presence with measurable characteristics, some useful questions immediately arise. For example, what causes sound? (Vibration.) What is sound made of? (Changes in pressure.) How does sound travel? (Energy transfer from one molecule to the next, like a row of dominoes.)

Once familiar with the physics of sound, we can consider the devices and structures that produce and record it. For example, how does a computer store sound? How does a radio send and receive "sound" signals?

At this point we are asking the right questions, which will be answered in the following modules. Get excited!

Next Lesson: What is Sound