Concept
Speed of sound
Overview
The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elastic medium. More simply, the speed of sound is how fast vibrations travel. 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 2.92 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 dry air (sea level 14.7 psi) is about 331 m/s (1,086 ft/s; 1,192 km/h; 740 mph; 643 kn). 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 dry air, deviating slightly from ideal behavior.
In colloquial speech, speed of sound refers to the speed of sound waves in air. The speed of sound varies from substance to substance, however: 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 in fresh water at 1481 m/s at a temperature of 20 °C (68 °F) (slightly more than 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), – 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.
Overview adapted from Wikipedia (CC BY-SA 4.0; see the article history for authors).
Possible passages
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This is the only animal that can do so. 6. There are also two jaws, the upper and the under. All animals move the lower jaw, except the river-crocodile, and this moves the upper jaw only. Below the nose are two lips, the flesh of which is very moveable. The mouth is the centre of the jaws and the lips. The upper part is called the roof of the mouth, the lower, the pharynx. The tongue is the organ of taste. This…
Aristotle, Aristotle's History of Animals In Ten Books
States what Speed of sound is; the author is tied to Speed of sound in the knowledge graph.
These preliminaries being concluded, the cases are called on. If it is a day for private cases, the private litigants are called. Four cases are taken in each of the categories defined in the law, and the litigants swear to confine their speeches to the point at issue. If it is a day for public causes, the public litigants are called, and only one case is tried. Water-clocks are provided, having small supply-tubes…
Aristotle, The Athenian Constitution
States what Speed of sound is; the author is tied to Speed of sound in the knowledge graph.
Those bodies, whose parts are in contact over large superficies, are called hard; those, whose parts are in contact over small superficies, are called soft; those, whose parts are in motion among one another, are called fluid.
Benedictus de Spinoza, Ethics
States what Speed of sound is.
Philosophers who discussed Speed of sound
Related ideas
- Isaac Newton
- Gas
- Classical mechanics
- Pierre Gassendi
- Atmosphere of Earth
- Oxygen
- Platonic Academy
- Archytas
- Special relativity
- Speed
- Thermodynamics
- Time
- Aristotle
- Water
- Pierre-Simon Laplace
- French Academy of Sciences
- Philosophiæ Naturalis Principia Mathematica
- Robert Boyle
- Peripatetic school
- Marin Mersenne
- American Civil War
- Electron
- Entropy
- Accademia del Cimento
Place in the tradition
Part of Pythagoreanism.