Hearing
Science: KS3, topic 3.3.6
Sound Waves
Sound is a longitudinal wave. Sound is caused by vibrations in the air.
Sound
- Sound is an example of a longitudinal wave.
- Sound is caused by vibrations in the air.
- Air particles vibrate and collide with other particles.
- The collisions make other particles vibrate.
Amplitude
- The amplitude of a sound is how loud it is.
- Amplitude is measured from the middle to the crest or trough, not top to bottom.
- Amplitude is measured in decibels (dB).
Amplitude and contact time
- The higher the amplitude of the sound, the less time you should be in contact with it.
- So be careful next time your headphones are loud for a long time!
Decibel scale
- The decibel scale goes from 0 to 180.
- 0 is the quietest.
- 180 is the loudest.
Everyday sound levels
- 10dB is around the sound of someone breathing.
- 50dB is the sound of someone talking to you.
- A motorcycle is 100dB.
- A jet plane is around 150dB.
Rocket launch and safety
- A rocket launch is around 180dB.
- You should not listen to sounds above 100dB for more than 15 minutes.
Test yourself on Hearing
Which are the correct decibel values for the following objects?
What is the maximum value on the decibel scale?
Which of these are true of amplitude?
What type of wave is sound?
The decibel scale goes from 0 to 180. What does a sound of 170dB tell you about the sound?