A Little Bit About Sound

Sounds are created by waves of high and low pressure travelling through the atmosphere. Sound waves can be thought of much as the waves that we can see in the water of the oceans; neither the ocean as a whole nor the water molecules in it have to move very far for ripples to appear to move across its surface. In the case of sound waves, the "ripples" are areas of changing pressure that move through the air out from the sound's source.

Our sense of hearing allows us to detect several dimensions of sound. We can discern the loudness, the pitch, and the timbre of a sound as well as where it came from. What we perceive as loudness is the amplitude of the sound, or the difference between the high- and low-pressure parts of the sound waves. (This corresponds to the height of waves at the ocean.) Pitch indicates the frequency of the sound, or how far apart or close together the waves are. Timbre represents the complexity of the sound, or the number of simpler wave patterns of which one complex sound is made.