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Sound: A physical definition could describe sound as a wave motion propagated in an elastic medium, traveling in both transverse and longitudinal directions, producing an auditory sensation, by the change of pressure at the ear.
Some other thoughts about sound might touch on its evernascence (always being born) and evanescence (vanishing away), the differences between visual and oral/aural culture; and how power, territory, property, ownership, and dominance could be expressed in each.
With sound and in hearing, one stands at the center of the universe, and gauges each phenomenon in relation to oneself - subjectification
With light and seeing, one stands a some distance from the object perceived - objectification.
Visually based words - focus, point, parallel, bottom line, &c.
Aural based words - resonance, tenor, tone, &c
For all the visual emphasis in our culture, we still highly prize the meanings embodied in words depicting the oral/aural such as "hearing" and "audit" to pursue truths.
Wave: A disturbance travelling through a medium by which energy is transferred from one particle of the medium to another without causing any permanent displacement of the medium itself. A sine wave, is the simplest form of this motion.
Cycle: A complete vibration. For a sine wave, it is the complete event starting with a rise from zero energy to a maximum amplitude, its return to zero, the rise to a maximum in the opposite direction, and then its return to zero.
Frequency: The number of cycles of vibration in a given unit of time. The number of cycles in a second is one Hertz (Hz), after the German physicist. Therefore 1Hz equals one cycle per second.
Period: the time it takes to complete one cycle.
Wavelength: The distance sound travels during one period, regardless of frequency.
Speed of Sound: at 21C (70°F), 344 meters per second, 1,129 ft per second, 1,233kph, 770mph. At freezing, the numbers are 331 m/s or 1087 ft/s. The Speed of sound in water is 1480 m/s or 4856 ft/s. More than 3,000 miles per hour.
Wavelength, Frequency & Speed of Sound
Wavelength x Frequency = Speed of Sound, or,
Wavelength = Speed of Sound / Frequency, and
Frequency = Speed of Sound / Wavelength
As frequency increases (becomes higher), the wavelength becomes longer.
As frequency decrease (becomes lower), the wavelength becomes shorter.
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