Reflection and Refraction of Waves
(Explanation by Huygens' Principle)

This applet is a tutorial which explains the reflection and the refraction of waves by the principle of Huygens. Explanations for each of the steps are provided in the text box. Whenever a step is finished, press the "Next Step" button. You can stop and continue the simulation by using the "Pause / Resume" button.  It is possible to vary the index of refraction of both media and the angle of incidence (be sure to hit return). The medium with the smaller index of refraction (the faster medium) is colored yellow.

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Christian Huygen (1629-1695) is said to have gained most of his insights into wave motion by observing waves in a canal.  Huygens was the first major proponent of the wave theory of light. 

Huygens' Principle
Every point on a wave front can be thought of as a new point source for waves generated in the direction the wave is traveling or being propogated.

In the simulation shown above, both reflection and refraction are shown from the point of view of Huygens' Principle.  A few sample points along the boundary of the two mediums are shown in pink and the wave is shown being reflected and refracted off these points.  In reality, there would be an infinite number of pink points along the way.  However the effect would still be the same.

This simlulation was created by Walter Fendt.
Walter Fendt, March 5, 1998
URL http://home.augsburg.baynet.de/walter.fendt/physengl/physengl.htm

Last modification: January 16, 1999

Explanation modified by Science Joy Wagon

Thanks to professor Taha Mzoughi (Mississippi State University) for the translation of the applet!

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