Sound
Wavelength of Sound Waves
- Distance between successive crests
Amplitude of Sound Waves
- Vertical height of the wave
- Loudness or volume
- Measured in decibels
Frequency of Sound Waves
- The number of cycles or waves passing a given point every second
- Pitch
- Measured in Hertz (Hz)
Frequency of Human Hearing
- Between 15 000 and 20 000 Hz
Speed of Sound
- 340 m/s at 15 °C in dry air (also called Mach 1)
- Sound travels faster in solids than in liquids than in gases
| SUBSTANCE | STATE AT ROOM TEMPERATURE | SPEED OF SOUND (m/s) |
| dry air | gas | 340 |
| helium | gas | 965 |
| kerosene | liquid | 1324 |
| distilled water | liquid | 1497 |
| sea water | liquid | 1531 |
| cork | solid | 500 |
| pine | solid | 3320 |
| glass | solid | 4540 |
| aluminium | solid | 5000 |
| brass | solid | 3480 |