Speed in different media
Everything learnt about waves in 4.1.3 — amplitude, wavelength, period, frequency and v = f λ — applies to sound too. What changes from medium to medium is the speed.
| Medium | Speed of sound |
|---|---|
| Dry air at 0 °C | 330 m s-1 |
| Air at 30 °C | 350 m s-1 |
| Water | 1400 m s-1 |
| A steel rod | 5000 m s-1 |
All the values are approximate.
- The higher the temperature of the air, the faster sound travels through it.
- The speed of sound in water is about four times its speed in air.
Not the speed of light
Sound at 330 m s-1 is almost a million times slower than light at 3 × 108 m s-1. The two are different kinds of wave: one mechanical, one electromagnetic.