30.2: Introduction
- Page ID
- 29289
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All waves begin as a vibration. For the vibration to produce sound, there must be a material through which the vibration may travel. The vibrations of atoms and molecules in air create compressions and rarefactions in the air.
Sound travels at an average speed of 343 m/s in air; this speed varies because it depends on the atmospheric pressure and temperature of the air. It takes time for the sound wave to travel. Light travels at a speed of 299,702,547 m/s in air. Light waves also take time to travel.
\[\text {speed} = \dfrac {\text{distance}}{\text{time}} \nonumber \]