Science 8: Unit C

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Science 8 Unit C Light and Optical Systems

• Topic 3 Refraction

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What is Refraction?

• Refraction is the bending of light rays as they
  enter a new medium (material)

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Why Does it happen?

• When light rays enter a thicker medium from a
  thinner medium they slow down and bend TOWARDS
  the normal. (eg. from air to glass)
• When light rays enter a thinner medium from a
  thicker one they speed up and bend AWAY from the
  normal (eg. from glass back to air.

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Law of Refraction

• Law of Refraction as the angle of incidence
  increases, the angle of refraction increases,
  though not necessarily by the same amount.
• NOTE refraction can also occur with the same
  material at two different temperatures.

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How are reflection, refraction, and absorption
different?

• The angle of incidence does not necessarily equal
  the angle of refraction.
• Reflection has to do with bouncing off a surface
  while refraction is bending of light rays.
• Absorption is the changing of light rays from
  light energy into another kind of energy (usually
  thermal energy).