Speed of sound Compression waves Steel: Strong forces, high density
Speed of sound Compression waves Water Medium forces, small distances
Speed of sound Compression waves Air Nearly no forces, large distances Temperature dependent!
Classification Growing frequency 20 Hertz 20 000 Hertz=20kHz Audible range 3000 Hz best hearing Infra sound Ultra sound Growing Wave length? Earthquakes, heavy traffic Medical imaging, dog whistles, bats
Wave lengths of the audible range 20 kHz: 20 Hz: Width of a finger Width of a house Objects in our environment are of the same order of size as the wave length of sound waves.
Sound and hollow tubes Sound: transverse wave, compression wave node Loop at open end node Loop at open end Both ends open: One end closed:
Resonances of tubes Fundamental 1 st overtone Closed tubes open tubes
Human ear The human ear canal is a tube of approximately 3 cm length. Determine the fundamental frequency.