Sound Art and Practice

Tuesday, August 15, 2006

THE PRACTICALITY OF SOUND


A Moment of Physics:
Regarding The Physicality of Sound

Author: Source Unknown

Many things in nature wiggle and jiggle. We call a wiggle in time a vibration. A vibration cannot exist in an instant, but needs time to move to and fro. We call a wiggle in time and space a wave.A wave cannot exist in one place,but must extend from one place to another.

Many things in nature wiggle and jiggle: Frequency refers to how often any regularly repeated event occurs in an assumed unit of time. The unit of frequency is measure in Hertz (Hz), the number of vibrations or cyles per second (cps).

A wiggle in time is a vibration. A vibrational motion can be produced in any medium made of molecules - earth, water, air and metal - if there is a disturbance of that medium's equilibrium (e.g. hammer striking a nail, strings of a guitar)

A vibration needs something to carry it along. The wave is the vehicle on which the frequency of vibrations travels (i.e., passing a message along in a bumper to bumper traffic jam).
Wave motion is the transfer of energy or information. Sound requires solids, gas and liquids, etc. to move it along.

Morale: Sound is a sensation caused by an object or objects that vibrate. When we put out a sound, a vibration at a certain rate (frequency is created). This vibration then becomes a sound wave if it is in a medium that allows it to travel. This information is transported by molecules (wave motion). On the other hand, noise is unwanted sound (very subjective). Pitch is how high or low a tone sounds to the ear (also subjective). Pitch is any periodic (repeats) frequency between 20 and 20,000 Hz. Non periodic means no regular pulse and frequency, and it will not produce a tone. Loudness (amplitude and volume) is also subjective.

Additional Info and Trivia

Physics Classroom
http://www.physicsclassroom.com/
Frequency Range of a Dog:
http://hypertextbook.com/facts/2003/TimCondon.shtml
Frequency Range of a Human
http://hypertextbook.com/facts/2003/ChrisDAmbrose.shtml
Dog Whistle
http://en.wikipedia.org/wiki/Dog_whistle
U Tube Fun
http://www.youtube.com/watch?v=_XYSfay-mi8

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