Core Practical: Investigating Refraction in a Glass Block

This lesson covers the core practical on investigating the refraction of light through a rectangular glass block, as required by the Edexcel GCSE Combined Science specification (1SC0). You need to know the method, how to draw and interpret ray diagrams, how to measure angles accurately, and how to draw valid conclusions.

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Aim

To investigate how the angle of incidence affects the angle of refraction when light passes through a rectangular glass block.

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Apparatus

Item	Purpose
Rectangular glass block	The medium through which light is refracted
Ray box (with single slit)	Produces a narrow beam of light
Power pack / batteries	Powers the ray box
Protractor	Measures angles of incidence and refraction
Ruler	Draws straight lines and normals
Sharp pencil	Marks ray positions accurately
Plain white paper	Placed under the glass block to trace rays
Optional: 4 pins	Alternative to ray box for tracing rays

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Method

Setting Up