This site features a nice textual introduction to site percolation theory on a square lattice, starting with brief introductions to random number generation on a computer and Monte Carlo algorithms and moving through basic site percolation concepts. Also included in the site are three applets. The first applet introduces random numbers obtained from a computer and histograms. This applet simulates a number of throws of a die and graphs a histogram of the outcome. The second applet illustrates the use of the Monte Carlo method. It shows how Monte Carlo methods can be used to estimate pi. The third applet very effectively guides users to the discovery of many basic concepts in percolation theory. Several exercises make the students participate in the discovery of these concepts. More advanced percolation concepts (L extrapolation, phase transitions, fractal nature of percolating clusters) are addressed in a more cursory fashion in the text, with some direction given as to how the third applet may be used to investigate them.
Please see the related reviews of other percolation sites at
Applet and href="http://www.merlot.org/artifact/ArtifactDetail.po?discipline=Mathematics&oid=1000000000000001722">style='mso-bidi-font-weight:bold'>Forest Fires and Percolation
This site provides a more advanced treatment of percolation than the Forest Fire and Percolation site. It functions at about the same level as the Percolation Applet,
which would be a nice complement to it as it focuses on different aspects of the theory.