For other uses, see Speed of sound (disambiguation).
An F/A-18 Hornet displaying rare localized condensation breaking the speed of sound
Sound measurements
Characteristic
Symbols
Sound pressure
p, SPL, LPA
Particle velocity
v, SVL
Particle displacement
δ
Sound intensity
I, SIL
Sound power
P, SWL, LWA
Sound energy
W
Sound energy density
w
Sound exposure
E, SEL
Acoustic impedance
Z
Audio frequency
AF
Transmission loss
TL
v
t
e
The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elastic medium. At 20 °C (68 °F), the speed of sound in air is about 343 m/s (1,125 ft/s; 1,235 km/h; 767 mph; 667 kn), or 1 km in 2.91 s or one mile in 4.69 s. It depends strongly on temperature as well as the medium through which a sound wave is propagating. At 0 °C (32 °F), the speed of sound in air is about 331 m/s (1,086 ft/s; 1,192 km/h; 740 mph; 643 kn).[1] More simply, the speed of sound is how fast vibrations travel.
The speed of sound in an ideal gas depends only on its temperature and composition. The speed has a weak dependence on frequency and pressure in ordinary air, deviating slightly from ideal behavior.
In colloquial speech, speed of sound refers to the speed of sound waves in air. However, the speed of sound varies from substance to substance: typically, sound travels most slowly in gases, faster in liquids, and fastest in solids. For example, while sound travels at 343 m/s in air, it travels at 1481 m/s in water (almost 4.3 times as fast) and at 5120 m/s in iron (almost 15 times as fast). In an exceptionally stiff material such as diamond, sound travels at 12,000 m/s (39,000 ft/s),[2] – about 35 times its speed in air and about the fastest it can travel under normal conditions.
In theory, the speed of sound is actually the speed of vibrations.
Sound waves in solids are composed of compression waves (just as in gases and liquids) and a different type of sound wave called a shear wave, which occurs only in solids. Shear waves in solids usually travel at different speeds than compression waves, as exhibited in seismology. The speed of compression waves in solids is determined by the medium's compressibility, shear modulus, and density. The speed of shear waves is determined only by the solid material's shear modulus and density.
In fluid dynamics, the speed of sound in a fluid medium (gas or liquid) is used as a relative measure for the speed of an object moving through the medium. The ratio of the speed of an object to the speed of sound (in the same medium) is called the object's Mach number. Objects moving at speeds greater than the speed of sound (Mach1) are said to be traveling at supersonic speeds.
^"Speed of Sound Calculator". National Weather Service. Retrieved 23 July 2021.
^"Speed of Sound". hyperphysics.phy-astr.gsu.edu. Retrieved 24 October 2022.
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the speedof the wind if the sound and wind are moving in the same direction. If the sound and wind are moving in opposite directions, the speedof the...
equal to the speedofsound. At Mach 0.65, u is 65% of the speedofsound (subsonic), and, at Mach 1.35, u is 35% faster than the speedofsound (supersonic)...
The speedofsound in any chemical element in the fluid phase has one temperature-dependent value. In the solid phase, different types ofsound wave may...
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soundspeed profile shows the speedofsound in water at different vertical levels. It has two general representations: tabular form, with pairs of columns...
approaches the speedofsound. When aircraft first approached the speedofsound, these effects were seen as constituting a barrier, making faster speeds very difficult...
In acoustics, the soundspeed gradient is the rate of change of the speedofsound with distance, for example with depth in the ocean, or height in the...
the speed (commonly referred to as v) of an object is the magnitude of the change of its position over time or the magnitude of the change of its position...
As aircraft speed increased designers began to encounter challenges associated with air compressibility at speeds near the speedofsound. The differences...
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aerodynamics, a hypersonic speed is one that exceeds five times the speedofsound, often stated as starting at speedsof Mach 5 and above. The precise...
finite speed, and observed that the speedof light is much faster than the speedofsound. In the 13th century, Roger Bacon argued that the speedof light...
seen at flight speeds close to the speedofsound (343 m/s at sea level), typically between Mach 0.8 and 1.2. The issue of transonic speed (or transonic...
capable of supersonic flight, that is, flying faster than the speedofsound (Mach 1). Supersonic aircraft were developed in the second half of the twentieth...
A sonic boom is a sound associated with shock waves created when an object travels through the air faster than the speedofsound. Sonic booms generate...
an ideal gas of constant composition the speedofsound depends only on temperature and not on pressure or density, the speedofsound in the atmosphere...
interval between emission and return of a pulse; the resulting time of flight, along with knowledge of the speedofsound in water, allows determining the...
density of the medium; and c is the speedofsound. Sound energy density Möser, M.; Müller, G. (2012). Handbook of Engineering Acoustics. Springer. p. 7...
of how fast the airplane is flying relative to the speedofsound. The measurement and indication of airspeed is ordinarily accomplished on board an aircraft...
for sound fixing and ranging channel), or deep sound channel (DSC), is a horizontal layer of water in the ocean at which depth the speedofsound is at...
at speedsof one and a half times the speedofsound or greater without the use of afterburner for extended periods in combat configuration." One of the...
hypersonic weapon is a weapon capable of travelling at hypersonic speed, defined as between 5 and 25 times the speedofsound or about 1 to 5 miles per second...
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