Acoustics term

1. Low-pitched notes are caused by low-frequency sound waves and high-pitched notes are caused by high-frequency waves
4. is the range of frequencies between any one frequency and double that frequency
8. frequency too high for human hearing
9. high frequency
12. is the distance between any two repeating points on a wave. The unit is the metre
13. include horns, organ pipes, mechanical fans and jet engines
17. A pure tone is sound of only one frequency, such as that given by a tuning fork or electronic signal generator
18. is the distance moved per second in a fixed direction. The unit is metres per second
19. is the frequency of a sound as perceived by human hearing

2. Sound is a variation in the pressure of the air of a type which has an effect on our ears and brain
3. include loudspeakers, guitar strings, vibrating walls and human vocal chords
5. is independent of the rate at which the sound vibrations occur, which means that the frequency of a sound does not affect its speed
6. travels faster in liquids and solids than it does in air
7. 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
10. 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
11. frequency too low for human hearing
12. The mechanical vibrations of sound move forward using wave motion
14. is the number of cycles of vibration per second. The unit is the hertz
15. occurs when the natural frequency of an object coincides with the frequency of any vibrations applied to the object
16. low frequency