Physics - Sound

SOUND

Sound waves are made by an object vibrating in the air.

Why a vibrating object creates sound waves

• The object's surface actually pushes and pulls on the air. 
• The waves on reaching your ears actually make your eardrums vibrate.

SOUND CANNOT TRAVEL THROUGH VACUUMS

SOUND WAVES ARE LONGITUDNAL.
Longitudnal waves vibrate in the same direction as they are travelling. However, light waves are transverse, meaning they vibrate 90 degrees to the direction they are travelling in.

Reflection

An echo is an example. For an echo you need;

• Smooth surface
  • A smooth surface means that the sound waves will not be absorbed by the surface.
• Hard surface / bare surface
  • A hard surface means that the echoes will be heard as the reflected sound…