1. Chapter 12, Section 2 Properties of Sound

2. Definitions
Amplitude: the amount of energy a wave carries; related to the density of the particles in the compressions and rarefactions
Intensity: the amount of energy that flows through a certain area in a specific amount of time
Loudness: the human perception of sound intensity; measured using the decibel (dB)

3. Definitions
Pitch: how low or high a sound seems to be; human perception of frequency
Frequency: the number of compressions or rarefactions of a sound wave that pass per second; human ears can hear frequencies from about 20 to 20,000 Hz

4. Definitions
Ultrasonic: sound waves with frequencies over 20,000 Hz that have medical and scientific uses
Infrasonic (subsonic): sound waves with frequencies less than 20 Hz; can’t be heard but we feel the vibration as a rumble
Doppler Effect: change in pitch of wave frequency due to a moving wave source; either the source of the wave or the observer can be moving

5. Sound links http://library.thinkquest.org/19537/Physics.html