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Lesson 5 of 11

5 min

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A spoon is in a glass of water. It looks bent at the surface.

A ray travels through air and reaches the surface.
Step 1 of 4
  1. A ray travels through air and reaches the surface.
  2. The normal is drawn square to the surface.
  3. Going straight through would look like this (dashed).
  4. The ray really bends toward the normal.

The rule

Refraction is light bending as it enters another clear material. It bends when the ray comes in at a slant. Air, water and glass are clear materials.

Light bends where it goes from air into water. It bends toward the normal. A ray along the normal does not bend.

Coming back out into air, the ray bends away from the normal. Measure angles from the normal. A bigger angle in air gives a bigger bend.

Swing the ray. See how much it bends.

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