Sound waves
Sound is the form of sound. Sound waves are a kind of mechanical wave, which is produced by the vibration of the object (sound source). The space of sound wave propagation is called sound field. In the gas and liquid medium is a longitudinal wave propagation, but in the solid medium may be mixed with shear waves. The frequency of sound received by any organ has its scope. The frequency of the sound waves that the human ear can hear is generally between 20 Hz and 2 x Hz. The frequency range of other animals is different, like dogs can hear more than 20kHz ultrasound, but can not hear the sound below 40 Hz. ...