refraction

• • refraction - when wave crosses boundary between materials at angle and changes direction
• • refraction can cause optical illusions as light waves appear to come from different position to actual source
• • density of material affects speed that wave is transmitted
  • the denser the material, the more slower light travels through it
• • if the ray crosses a boundary and slows down, it will bend towards the normal
  • of the ray crosses a boundary and speeds up, it will bend away from the normal
• • the wavelength of a wave changes when it is refracted but the frequency stays the same
  • if the wave travels along the normal, it will change speed but is not refracted
  • if a wave slows down, its wavelength decreases
  • so, wave speed = frequency x wavelength
• • the speed and directions changes of light during refraction:
  • F - Faster
  • A - Away
  • S - Slower
  • T - Towards