Science Simulation and Interactive Learning Software
Astronomy
Softseek Index of Astronomy Simulations (recommended)
General Science Subjects (includes Biology, Chemistry, other fields)
Softseek General Index of Science Simulations and Learning Software (recommended)
D. Henton's List of Educational Java Demos in Science (requires Windows95 or advanced Macintosh)
Physics
Chemistry
Very simple interactive Periodic Table (can be downloaded, even for Windows 3.1; also runs on the web)
Periodic Table from Los Alamos Lab (works via web) -- good for educational use
WebElements -- award-winning from University of Sheffield, England; includes advanced chemistry information
Biology