Sound Waves?

Question

Is speaking a longitudinal wave or a transverse wave. Why is that so. Also does rarefaction have a minimum or maximum pressure variation and why?

Thanks

Answer 1

Sound is a longitudinal wave, since it consists of pressure variations along the direction of travel. During the rarefaction part of a pressure wave, absolute pressure cannot go below zero. This contrasts with the compression part, where pressure can increase almost without limit if the sound energy is high enough. Thus very loud sounds can inherently contain distortion, since the minimum and maximum pressure half-cycles can be differently shaped.