Refraction

• Refraction of light waves


  When waves change direction as they pass from one medium to another, like from air into glass
• Refraction


  • Waves travel at different speeds in different materials or mediums
  • This happens because different mediums have different densities
  • Electromagnetic waves like light - the higher the density of the material, the slower the wave will travel through it
• Refraction of waves


  1. Wave travels from a less dense medium to a more dense medium

  2. Wave slows down as it passes into the more dense medium

  3. If wave hits the boundary at an angle, it will be refracted

  4. Wave bends towards the normal (perpendicular line) when passing into a more dense medium
• Drawing ray diagrams for refraction

  1. Draw normal (perpendicular line) at point of incidence

  2. If wave enters more dense medium, refracted ray bends towards normal

  3. If wave exits more dense medium, refracted ray bends away from normal

  4. Add angle of incidence and angle of refraction
• Frequency and wavelength


  • Frequency stays the same, only wavelength changes
  • If wave speed increases, wavelength increases
  • If wave speed decreases, wavelength decreases
• White light through a triangular prism

  Different wavelengths (colors) bend to different degrees, spreading out like a rainbow