CDIS 4313 Lecture Notes - Lecture 2: Longitudinal Wave, Wind Wave, Vocal Folds
Document Summary
Occurs when some disturbance creates changes in pressure in a gas, liquid, or solid medium. Any kind of movement can create a disturbance. Pressure changes created by disturbance are transmitted through a medium and may end up at a listener"s ear to be perceived as sound. The primary medium we are concerned with is gas (known as air!) Gas composed of 78% nitrogen and 21% oxygen, with some other elements. Molecules of air are constantly moving around at high speeds in random patterns: brownian motion. Fast random movement makes gas a little different form liquids and solids. Air pressure is air pushing own on the earth"s surface. Fricatives would be turbulent because articulators are changing the flow of air. Brownian motion creates relatively stable ambient pressure (p am) Sound occurs when a disturbance creates alternating increases and decreases in p am.