CMD 278 Lecture Notes - Lecture 9: Rubber Band, Simple Harmonic Motion, Rarefaction
Document Summary
What is sound: a disturbance of particles in a medium. There are 3 necessary components for sound production: energy source, body capable of vibration, transmitting medium (gas, liquid, solid) Sounds waves of tiny fluctuations in air pressure that propogate from the source. Pressure changes from sound waves = localized disturbances from ambient air pressure. Air consists of billions of particles called molecules. Air has the following properties: mass, elasticity, inertia. Mass any form of matter solid, liquid, gas. Inertia common property of all matter an object in motion remains in motion; an object at rest remains at rest until it is acted upon by external force. Dissipation of vibratory energy is called damping. Pressure force distributed over a particular area: measured in dyne/cm2 or more recently pa, . 0002dyne/cm2 = 20 micropascals. Therefore, sound occurs when there are pressure variations from atmospheric pressure: these variations occur with a frequency of occurrence that is detectable by the auditory system.
