Speed of sound Definition and 271 Threads

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 metres per second (1,235 km/h; 1,125 ft/s; 767 mph; 667 kn), or a kilometre in 2.9 s or a mile in 4.7 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 is 1192 km/h, 741 mph.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 1,481 m/s in water (almost 4.3 times faster) and at 5,120 m/s in iron (almost 15 times faster). In an exceptionally stiff material such as diamond, sound travels at 12,000 metres per second (39,000 ft/s),— about 35 times its speed in air and about the fastest it can travel under normal conditions.
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, 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 fluid is called the object's Mach number. Objects moving at speeds greater than Mach1 are said to be traveling at supersonic speeds.

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  1. Dante Meira

    B Speed of sound in steel at different temperatures?

    Is there a formula to calculate the speed of propagation of sound waves through steel (a steel bar, for example) according to the temperature of steel?
  2. S

    I How fast does a blastwave travel?

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  3. K

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  4. M

    Speed of sound from resonant length of tube vs tuning fork wavelengths

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  5. fascinated

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  6. R

    Variation of the Speed of Sound in metals under tension

    In a block of metal, each metal has a characteristic speed of sound. When metal is under tension, such as a guitar string, the speed rises as the tension increases. How does the speed vary (in a block say) as a function of tension along each of the three axes? I am assuming that transverse...
  7. snoopies622

    Confusion about the derivation of the speed of sound

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  8. E

    Speed of sound in a relativistic fluid

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  9. L

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  10. T

    I Speed of Sound & Light: Is it True?

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  11. G

    B Speed of Light & Sound: Revolutionary Phenomenon?

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  12. C

    Trig type question -- Speed of sound in water and in air

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  13. J

    The hot chocolate effect to investigate the effects on speed of sound

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  14. B

    Speed of sound related to absolute temperature

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  15. greg_rack

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  16. Harini Krishna

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  17. anonymous99

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  18. T

    Adiabatic approximation in the derivation of the speed of sound

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  19. K

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  20. Creed

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  21. D

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  22. V

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  23. F

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  24. T

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  25. Dr. Courtney

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  26. V

    Speed of Sound Experiment: Hear the Results

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  27. P

    A Measuring Viscosity via the Speed of Sound

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  28. S

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  29. P

    Speed of sound: viscosity dependece in liquids and solids

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  30. B

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  31. Superfluid universe

    I How is this formula for the speed of sound derived?

    c² = (n/m) ∂²U/∂n² where U = vacuum energy density as a function of the quasiparticle density n = quasiparticle number density m = bare mass of quasiparticle Is there a book, article where this formula is explained? Thank you.
  32. M

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  33. F

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  34. S

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  35. C

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  36. K

    Speed of sound in steel dependance on temperature

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  37. M

    Solids with different sound velocity at diffrent tempratures

    i work on phononic crystals and i want to find solids with diffrent sound velocities and mass density in diffrent temprature i can just find BST but i need more matherials please help me my friends best regards
  38. Y

    Can the speed of sound in air be faster?

    Sound is vibration of air molecules knocking into each other. Intuitively, it seems the faster a molecule travels before hitting another, the faster the propagation of sound. Can't you hit air molecules harder, so the air molecules will travel faster and spend less time between collisions, and...
  39. baldbrain

    Speed of Sound using a Resonant tube

    Homework Statement In the experiment for the determination of the speed of sound using a resonance tube, the diameter of the column tube is 4 cm. The frequency of the tuning fork is 512 Hz. The air temperature is 38° C in which the speed of sound is 336 m/s. The zero of the meter scale...
  40. lightofthemoon

    What is the Speed of Sound in this Lab Setup?

    Homework Statement In this part of the lab you tracked a single peak as you moved a microphone in order to get a good value of the speed of sound. This question will lead you through a similar process with just two measurements. (The lab set up: speaker emitting the signal faced one microphone...
  41. T

    How long does it take for sound to travel 1 mile at a speed of 740 mph?

    Let's assume a speed of sound of approximately 740 mph at sea level. If I there are two aircraft traveling in formation 1 mile apart (one in front of the other) at 730 miles per hour, how long will it take for the sound of single gunshot fired from the trailing aircraft to reach the lead...
  42. Surya97

    Why is there a set speed of sound in a certain medium?

    Why does sound always move at the local speed of sound in a medium (in other words, why is there a set speed of sound for certain medium)? I understand that sound is a compression wave, but shouldn't a louder sound (i.e. one with a higher amplitude) move faster? What about a higher pitch noise...
  43. F

    What is the speed of sound from a fast-approaching train?

    Someone once said, there are no stupid questions, just stupid people. All the questions I have read about sound coming from an approaching object only seem to deal with the frequency of sound, not its speed. So with that in mind, I have the following (hopefully non-stupid) question: A train is...
  44. N

    Kinematics/speed of sound question

    Homework Statement A stone is dropped in a well. The splash is heard 3s later. What is the depth of the well? Homework Equations constant acceleration equations take speed of sound to be 343 m/s. The Attempt at a Solution For the stone: u = 0 a = g s = ut + 0.5at^2 subbing it all in you get...
  45. F

    I A light wave and a sound wave travelling together

    If we could imagine a medium that could slow down light quite significantly, if a sound wave and a light wave were both passing through this medium, would the sound wave see the light wave passing by at the speed that light passes through that medium or would it see it passing by at the speed...
  46. F

    I Speed of light and speed of sound both constant

    I believe that the speed of sound is constant in the same medium as is the speed of light. I would like to understand why we need the the theory of relativity to explain the speed of light being constant but I believe it is not used to explain why the speed of sound is constant within the same...
  47. G

    Sound in a gas of non-interacting particles?

    Hi. In some statistical approaches (e.g. canonical ensemble), the particles of an ideal gas are non-interacting. Still, it's possible to derive the ideal gas law and other thermodynamic relations. Wikipedia gives an equation for the speed of sound in an ideal gas. How can there be waves in a...
  48. C

    Confusion regarding the speed of sound in wind

    One of my students asked me the seemingly innocuous question of "how does wind affect the speed of sound?". My immediate thought was that the velocity of the wave would be the vector sum of the velocity of the wind and the velocity of sound waves in still air. However, upon further reflection I...
  49. Erenjaeger

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  50. B

    How to graph a linear relationship between T and v of sound?

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