The refraction applet is very simple to operate. To adjust the incident angle, simply move the slider labeled "Incident Angle" and the wave angle will change. To change media, click on the "Refraction Medium" arrow tab and select a different medium. The refracted wave will change with respect to both the angle of refraction and wave velocity to simulate properties of the new medium. The wavelength of the incident beam can also be changed by adjusting the "Wavelength" slider. As the value of the wavelength is changed, the color will change to reflect the color of light at the given wavelength.
Although not apparent with this tutorial, the index of refraction has been found to vary with the frequency of radiation. This phenomena occurs for all transparent optical media, and has been termed dispersion. It is the dispersion of light by glass that is responsible for the familiar splitting of light into its component colors by a prism.
Matthew J. Parry-Hill and Michael W. Davidson - National High Magnetic Field Laboratory, 1800 East Paul Dirac Dr., The Florida State University, Tallahassee, Florida, 32310.