This simulation demonstrates how a prism works. White light shines in from the left. You may be surprised to see that it goes straight into the prism, without splitting up inside the prism. Why is this? This is something of a special case.

The light is split up into different colors when it emerges from the prism. This is because of the dispersion of the glass that the prism is made from. Dispersion means that the index of refraction varies depending on the wavelength of light - in general, the index of refraction of the glass increases as the wavelength of the light decreases. The net result is that light of smaller wavelengths experiences a larger change in direction when it emerges from the prism into the surrounding medium.

Something odd seems to happen when the dispersion is high, the prism angle is large, and the medium surrounding the prism has a low index of refraction. Can you explain what is going on?

Simulation written by Andrew Duffy, and first posted on 3-21-2018.

Creative Commons License
This work by Andrew Duffy is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
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