An area of physics devoted to the study of the production, transmission, and reception of sound.
The maximum displacement of a vibrating material. In wave motion, amplitude is the "size" of a wave, and for sound waves, amplitude indicates the intensity or volume of sound.
For a sound wave, a cycle is a single complete vibration.
A unit for measuring intensity of sound. Decibels, abbreviated dB, are calibrated along a logarithmic scale whereby every increase of 10 dB indicates an increase in intensity by a factor of 10. Thus if the level of intensity is increased from 30 to 60 dB, the resulting intensity is not twice as great as that of the earlier sound—it is 1,000 times as great.
The ability to perform work, which is the exertion of force over a givendistance. Work is the product of force and distance, where force and distance are exerted in the same direction.
In wave motion, frequency is the number of waves passing through a given point during the interval of one second. The higher the frequency, the shorter the wavelength. Measured in Hertz, frequency is mathematically related to wave speed, wavelength, and period.
The repeated movement of a particle about a position of equilibrium, or balance.
A unit for measuring frequency, named after nineteenth-century German physicist Heinrich Rudolf Hertz (1857-1894). High frequencies are expressed in terms of kilohertz (kHz; 10 3 or 1,000 cycles per second) or megahertz (MHz; 10 6 or 1 million cycles per second.)
Intensity is the rate at which a wave moves energy per unit of cross-sectional area. Where sound wavesare concerned, intensity is commonly known as "volume."
A wave in which the movement of vibration is in the same direction as the wave itself. A sound wave is an example of a longitudinal wave.
Physical substance that has mass; occupies space; is composed of atoms; and is ultimately convertible to energy.
Material through which sound travels. (It cannot travel through a vacuum.) The most common medium (plural, media) of sound transmission experienced in daily life is air, but in fact sound can travel through any type of matter.
The vibration experienced by individual waves even as the wave itself is moving through space. Oscillation is a type of harmonic motion, typically periodic, in one or more dimensions.
For wave motion, a period is the amount of time required to complete one full cycle. Period is mathematically related to frequency, wavelength, and wave speed.
Motion that is repeated at regular intervals. These intervals are known as periods.
A decrease in density.
Sound waves with a frequency above 20,000 Hertz, which makes them in audible to the human ear.
An area entirely devoid of matter, including air.
The distance between a crest and the adjacent crest, or the trough and an adjacent trough, of a wave. Wavelength, symbolized by λ (the Greek letter lambda) is mathematically related to wave speed, period, and frequency.
A type of harmonic motion that carries energy from one place to another without actually moving anymatter.
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