Speed of Sound
- The velocity (speed) of a wave is also mathematically related to distance and time, as shown in the following formulas.
- In terms of speed:
- In terms of distance:
- In terms of time:
- We saw in the lesson ‘Waves’ that the speed of a wave depends on the medium through which it travels.
- We saw that mechanical waves, such as sound waves, travel fastest in solids and slowest in gases.
- This is because the more closely packed particles in a substance are, the more efficiently they can transfer the wave.
- The speed of sound in air is approximately 340 m/s.
- The speed of sound in water is approximately 1500 m/s.
- The speed of sound in concrete is approximately 3000 m/s.
- The speed of sound is also affected by temperature. Particles are moving faster in hotter objects than in cooler objects, therefore sound waves can travel more efficiently through them.
- The speed of sound in air at 0 °C is approximately 331 m/s.
- The speed of sound in air at 25 °C is approximately 346 m/s.
- The speed of sound in air at 45 °C is approximately 358 m/s.
- The speed of sound in air is also affected by the composition and density of the air, including the amount of water vapour.
- For example, sound travels slightly faster in humid air than in dry air.
(Header image: Thaut Images, Adobe Stock)