Properties of Sound Waves

Speed of sound

• in air: 340 m/s
• in water: 1480 m/s

Amplitude range of hearing (humans)

• Threshold of audibility: 0.00002 N/m$^2$
• Threshold of feeling (or pain!): 200 N/m$^2$

Frequency range of hearing

• humans: 20 - 20 000 Hz
• dogs: 20 - 45 000 Hz
• beluga whale: 1000 - 123 000 Hz

Period of lowest and highest audible frequencies

• 1/20 Hz = 0.05 s $\quad$ 1/20 000 Hz = 0.05 ms

Shortest audible wave

• 340/20000=1.7cm

Longest audible wave

• 340/20=17m