c. Speed of sound
1) 332 m/s in air at 0 C.
2) Changes by 0.6 m/s for every Celsius degree from 0 C.
3) Subsonic – slower
4) Supersonic – faster than sound (Mach 1 = speed of sound)
5) Sonic boom (pressure cone)
d. The Doppler effect – the change in pitch due to a moving wave source.
1) Objects moving toward you cause a higher pitched sound.
2) Objects moving away cause sound of lower pitch.
3) Used in radar by police and meteorologists and in astronomy.
4. Musical sound
a. Noise has no pattern.
b. Music has a pattern and deliberate pitches.
c. Sound quality describes differences of sounds that have the same pitch and loudness.
d. Every instrument has its own set of overtones.
e) Beats are pulsing variations of loudness caused by interference of sounds of slightly different frequencies.
5. Uses of sound
a. Acoustics – the study of sound.
Soft materials dampen sound; hard materials reflect it (echoes and reverberations).
b. SONAR – Sound Navigation and Ranging (echolocation).
c. Ultrasound imaging
d. Kidney stones & gallstones.