School of Physics Lecture Demonstration Manual

Oa-3 Ray Tracing

Published: Wednesday 15 March 2006 - Updated: Monday 28 March 2011


To demonstrate ray tracing through various optical elements including lenses, mirrors and prisms.



Click on pictures to enlarge.

Ray Tracing Diagram

Ray Tracing with Red Laser

Ray Tracing with Green Laser 1

Ray Tracing with Green Laser 2


The optical component is set up within the smoke box and a lighted incense stick is introduced into the apparatus. It has been found best to remove the smoke source and allow the apparatus to stand for 5 minutes. This clears the smoke box of the heavier particles and the smoke box appears clear but still contains enough fine smoke particles to produce brilliant scattering. The laser may be mounted on a labjack and raised or lowered as required or alternatively passed through a series of slides to produce multiple beams.

Safety notes

Electrical safety 

Sharps safety 

Fire/Burn safety

Laser safety


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