Acoustics


 * Speed: the rate of travel of a sound wave through an elastic medium.
 * Frequency: is the number of waves that pass a point per second.
 * Wavelength: is the distance between maching points of a wave.
 * Longitudinal: is when the waves vibrate parallel to the direction of travel of the wave.
 * Transverse: is when the waves vibrate at rigth angles to the direction of travel of the wave.