Visible light – the eye, drawing ray diagrams

The videos aim to show and explain several aspects of visible light. The video lesson immediately below explains the way that the eye works in terms of physics and optics by showing the individual parts of a dissected eye and illustrating the function of each. Suitable for 14 to 16 year old science or anyone meeting this topic for the first time.

The video at the bottom of the page explains how to draw ray diagrams for a convex / converging lens used as a projector and as a magnifying glass. Combining demonstrations with a real lens and laser streaks though the centre and edges to show why only certain "rays" are traced through on the diagram.

Notes on aspects of visible light, including reflection, refraction, diffraction and interference are here


A much larger range of video lessons are available on data stick, details here


and optical fibres

The video below is an introduction to how optical fibres can be simply made, how they work and what they are used for. Suitable for 14 to 16 year old physics study (British GCSE)

The eye

Drawing ray diagrams for converging lenses.

Optical fibres