Total Internal Reflection in a Prism


A sketch of the apparatus
A sketch of the apparatus

See the teacher though the prism. Related to binoculars, suitable for large lecture theatre with video camera.



Principles Illustrated

Total internal reflection in a prism. This technology is used in binoculars.

NCEA & Science Curriculum

SCI 1.3, PHYS 1.4, PHYS 2.3


The use of the video camera, computer running video capture software and a projector make this suitable for a large lecture hall. In a small classroom just set up the prism and have students look into the prism.

Some adjustment is required. Try not to have light shining on the face of the prism that the camera is pointed at as reflections will be annoying.

Make sure the video camera is not set to auto focus. It will try to focus on the prism rather than the teacher!

A sketch of the apparatus
A sketch of the apparatus
Close-up of the apparatus
Close-up of the apparatus




Individual teachers are responsible for safety in their own classes. Even familiar demonstrations should be practised and safety-checked by individual teachers before they are used in a classroom.


Prisms in binoculars

Teaching Resources

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This teaching resource was developed with support from

The MacDiarmid Institute
Faculty of Science, Victoria University of Wellington
School of Chemical and Physical Sciences, Victoria University of Wellington


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