Across
- 1. is the distance moved per second in a fixed direction. The unit is metres per second (m/s)
- 3. is the frequency of a sound as perceived by human hearing.
- 6. Sound If an object that produces sound waves vibrates 100 times a second,
- 11. in the air with frequencies of vibration which are too low (infrasound) or too high (ultrasound) to be heard by human hearing are also regarded as sound.
- 12. is the number of cycles of vibration per second. The unit is the hertz (Hz)
- 13. frequency too high for human hearing
- 15. is the distance between any two repeating points on a wave. The unit is the metre (m)
- 17. frequency too low for human hearing
- 18. low frequency
- 20. frequencies equal to whole-number multiples of the fundamental frequency.
Down
- 2. is the range of frequencies between any one frequency and double that frequency.
- 4. 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.
- 5. A sound wave travels away from its source with a speed of 344 m/s (770 miles per hour) when measured in dry air at 20°C.
- 7. high frequency
- 8. Every object has a natural frequency which is the characteristic frequency at which it tends to vibrate when disturbed.
- 9. The mechanical vibrations of sound move forward using wave motion.
- 10. is sound of only one frequency, such as that given by a tuning fork or electronic signal generator
- 14. resonance may occur in many ___________ systems
- 16. object 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.
- 19. is a variation in the pressure of the air of a type which has an effect on our ears and brain.