Page 43 - WAVES

6.6 Sound waves

1. Sound is a form of energy propagated How is sound produced by a vibrating
as waves that make our eardrums
objects ?
vibrate.

2. Sound waves are caused by  Sound waves are produced when a vibrating
vibrating objects. object causes the air molecules around it to

3. Sound waves are longitudinal waves. vibrate.
 When a tuning fork vibrates, layers of air

vibrate and the sound energy is propagated
through the air around it in the form of waves.

How the loudness relates to amplitude?  When the tuning fork moves forwards, the air
is compressed.
The loudness of the sound depends on its  When the tuning fork moves backwards, the

amplitude. air layers are pulled apart and cause a
If the amplitude is increased, the loudness rarefaction.
increases.  Therefore, a series of rarefactions and

compressions will produce sound.

How the pitch relates to frequency ?

direction
A high pitch sound corresponds to a high λ propagation
frequency and a low pitch sound Vibration

corresponds to a low frequency of vibration.

compression rarefaction

Tuning Fork
43