WavesDeep Dive

Why Refraction Happens

Part of Reflection & RefractionGCSE Physics

This deep dive covers Why Refraction Happens within Reflection & Refraction for GCSE Physics. Revise Reflection & Refraction in Waves for GCSE Physics with 15 exam-style questions and 15 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 4 of 13 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.

Topic position

Section 4 of 13

Practice

15 questions

Recall

15 flashcards

💡 Why Refraction Happens

Refraction occurs because different media have different optical densities, which affects how fast light (or any wave) can travel through them. When a wave front hits a boundary at an angle, one side of the wave hits the new medium first and slows down, while the other side is still in the old medium at its original speed. This causes the wave front to rotate — bending the direction of travel.

A helpful analogy: imagine a marching band moving across a field and hitting a patch of mud at an angle. The first soldiers to enter the mud slow down; the others are still on grass and moving fast. The whole row of soldiers pivots — this is exactly what happens to light at a glass surface.

Keep building this topic

Read this section alongside the surrounding pages in Reflection & Refraction. That gives you the full topic sequence instead of a single isolated revision point.

Practice Questions for Reflection & Refraction

According to the law of reflection, the angle of incidence is:

  • A. Always 90 degrees
  • B. Greater than the angle of reflection
  • C. Equal to the angle of reflection
  • D. Measured from the reflecting surface
1 markfoundation

Explain why a ray of light bends when it passes from air into water.

3 marksstandard

Quick Recall Flashcards

What is refraction?
Change in direction when light enters a different medium (due to speed change)
Law of reflection
Angle of incidence = Angle of reflection

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