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The speed of sound (blue) depends only on the complicated temperature variation at altitude and can be calculated from it since isolated density and pressure effects on the speed of sound cancel each other. The speed of sound increases with height in two regions of the stratosphere and thermosphere, due to heating effects in these regions.
Sound intensity, also known as acoustic intensity, is defined as the power carried by sound waves per unit area in a direction perpendicular to that area, also called the sound power density and the sound energy flux density. [2] The SI unit of intensity, which includes sound intensity, is the watt per square meter (W/m 2).
Sound propagates as mechanical vibration waves of pressure and displacement, in air or other substances. [5] In general, frequency components of a sound determine its "color", its timbre . When speaking about the frequency (in singular) of a sound, it means the property that most determines its pitch . [ 6 ]
In physics, sound energy is a form of energy that can be heard by living things. Only those waves that have a frequency of 16 Hz to 20 kHz are audible to humans. However, this range is an average and will slightly change from individual to individual.
For example, sound moving through wind will have its speed of propagation increased by the speed of the wind if the sound and wind are moving in the same direction. If the sound and wind are moving in opposite directions, the speed of the sound wave will be decreased by the speed of the wind. The viscosity of the medium.
If the wave is a sound wave and the sound source is moving faster than the speed of sound, the resulting shock wave creates a sonic boom. Lord Rayleigh predicted the following effect in his classic book on sound: if the observer were moving from the (stationary) source at twice the speed of sound, a musical piece previously emitted by that ...
There are many kinds of transduction process that convert energy from some other form into sonic energy, producing a sound wave. There is one fundamental equation that describes sound wave propagation, the acoustic wave equation, but the phenomena that emerge from it are varied and often complex. The wave carries energy throughout the ...
The speed of sound (i.e., the longitudinal motion of wavefronts) is related to frequency and wavelength of a wave by =.. This is different from the particle velocity , which refers to the motion of molecules in the medium due to the sound, and relates to the plane wave pressure to the fluid density and sound speed by =.