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GCSE Physics Required Practical: Investigating Reflection and Refraction of Light

Key Stage 4

Meaning

Investigate the reflection and refraction of light.

Experiment 1: Reflection from a Plane Mirror

Method

RequiredPracticalReflection1.png
RequiredPracticalReflection2.png
A pair of diagrams of the apparatus used to investigate the reflection of light.
  1. Place a plane mirror in the centre of a piece of paper and draw a pencil line along its reflective side.
  2. Use a ray box and a slit to allow a single beam of light to be incident on the surface of the mirror at an angle less than 90°.
  3. Place a pair of x's on the incident ray and along the reflected ray.
  4. Remove the ray box and mirror.
  5. Use a ruler to join the x's with a pair of lines leading to the mirror to show the direction of the incident and reflected rays.
  6. Use a protractor and ruler to draw a normal line at right angles to the surface of the mirror at the point the light rays meet the mirror.
  7. Use the protractor to measure the 'i' the angle of incidence and 'r' the angle of reflection.
  8. Repeat this procedure for a number of different angles of incidence.

Improving Accuracy

Drawing the rays longer and using a larger protractor may reduce the error in reading the protractor and improve accuracy.

Experiment 2: Refraction from a Rectangular Glass Block

Method

RequiredPracticalRefraction1.png
RequiredPracticalRefraction2.png
A pair of diagrams of the apparatus used to investigate the refraction of light.
  1. Place a rectangular glass block in the centre of a piece of paper and draw a pencil line around the outside.
  2. Use a ray box and a slit to allow a single beam of light to be incident on the surface of the glass block at an angle less than 90°.
  3. Place a pair of x's on the incident ray and along the emergent ray.
  4. Remove the ray box and glass block.
  5. Use a ruler to join the x's with a pair of lines leading to the glass block to show the direction of the incident and emergent rays.
  6. Join the emergent ray and the incident ray with a line to represent the refracted ray.
  7. Use a protractor and ruler to draw a normal line at right angles to the surface of the glass block at the point the light rays meet the glass block.
  8. Use the protractor to measure the 'i' the angle of incidence and 'r' the angle of refraction.
  9. Repeat this procedure for a number of different angles of incidence.

Improving Accuracy

Drawing the rays longer and using a larger protractor may reduce the error in reading the protractor and improve accuracy.