Video encyclopedia

Speed of sound

Physical phenomena

The speed of sound is the distance travelled per unit time by a sound wave as it propagates through an elastic medium. In dry air at 0 °C (32 °F), the speed of sound is 331.2 metres per second. At 20 °C (68 °F), the speed of sound is 343 metres per second, or a kilometre in 2.91 s or a mile in 4.69 s.


  • General 

  • History 

  • Basic concepts 

  • Equations 

  • Dependence on the properties of the medium 

  • Practical formula for dry air 

  • Details 

  • Effect of frequency and gas composition 

  • Mach number 

  • Experimental methods 

  • Non-gaseous media 

  • Gradients