beats- a throbbing variation on the loudness of sound caused by interference when two tones of slightly different frequencies are sounded together.
compression- in sound, a pulse of compressed air(or other matter); opposite of rarefaction
forced vibration- the vibration of an object that is made to vibrate by another vibrating object that is nearby.
infrasonic- tern applied to sound pitch too low to be heard by the human ear, that is, below 20 hertz.
natural frequency- a frequency at which an elastic object, once energized, will vibrate,. Minimum energy is required to continue vibration at the frequency. Also called resonant frequency.
pitch- term that refers to how high or low sound frequencies appear to be.
rarefaction- the bouncing back of a particle or wave that strikes the boundary between two media.
resonance- a phenomenon that occurs when the frequency of forced vibration on an object matches the object's natural frequency, and a dramatic increase in amplitude results.
ultrasonic- term applied to sound frequencies above 20,000 hertz, the normal upper limit of human hearing.