Florida State University
Florida State University: Microscopy Primer: Anatomy of the Microscope
The premier web site on the physics of microscopy. Includes several pages and numerous Java applets about microscopes and refraction. Thorough, well-illustrated, interactive, fun, and educational. What more can one ask for?
Other
University of Athens: Distribution Diagrams of Polyprotic Acids
The derivation of the alpha-function of a polyprotic acid is given. Includes applet that requires Java plug-in. Also available in Greek.