Acoustics term

2. The mechanical vibrations of sound move forward using wave motion
6. high frequency
8. occurs when the natural frequency of an object coincides with the frequency of any vibrations applied to the object
9. low frequency
10. is the frequency of a sound as perceived by human hearing
11. compresses adjacent particles of air as it moves in one direction and leaves the particles of air ‘spread out’ as it moves in the other direction
12. frequency too low for human hearing
16. is independent of the rate at which the sound vibrations occur, which means that the frequency of a sound does not affect its speed
19. A pure tone is sound of only one frequency, such as that given by a tuning fork or electronic signal generator
20. the nature of a sound wave, such as shown in the earlier figure, means that the vibration of the wave has alternate changes in amplitude called phases

1. include loudspeakers, guitar strings, vibrating walls and human vocal chords
3. is the distance between any two repeating points on a wave. The unit is the metre
4. is the number of cycles of vibration per second. The unit is the hertz
5. frequency too high for human hearing
7. include horns, organ pipes, mechanical fans and jet engines
13. Low-pitched notes are caused by low-frequency sound waves and high-pitched notes are caused by high-frequency waves
14. Sound is a variation in the pressure of the air of a type which has an effect on our ears and brain
15. travels faster in liquids and solids than it does in air
17. is the range of frequencies between any one frequency and double that frequency
18. is the distance moved per second in a fixed direction. The unit is metres per second