Refraction, Diffraction and Musical Sounds

Refraction, Diffraction and Musical Sounds

1. Refraction

   • The change of direction of waves when they travel across a boundary
   • When a light ray refracts as it travels from air to glass the angle of refraction is less than the angle of incidence
     • The light ray refracts towards the normal
   • When a light ray refracts as it travels from glass into air the angle of refraction is more than the angle of incidence
     • The light ray refracts away from the normal

2. Diffraction

   • Diffraction is the spreading out of waves when they pass through a gap or round an obstacle
   • The narrower a gap is the greater the diffraction
   • If the radio waves do not diffract enough when they go over hills, radio and TV reception will be poor

3. Musical sounds

   • The pitch of a note increases if the frequency of the sound waves increase
   • The loudness of a note increases if the amplitude of the sound waves increases
   • Vibrations created in an instrument when it is played produce sound waves