Math

Ask Dr. Math: Explore the math forum, browse the answers to questions already posed or submit your own. This site is divided into grade levels from elementary school to college.
Chemistry Coach: The Chemistry Coach site formerly maintained by Dr. Bob Jacobs of Wilton High School (he passed away in 2006). This resource (although not being updated) is available through an Internet archive.
CuriousMath.com: Here you'll find tricks and rules for quickly calculating certain types of math problems.
ExploreLearning - Gizmos: Interactive multimedia activities to help students explore, visualize, and learn mathematical concepts.
The MacTutor History of Mathematics Archive: See biographies of more than 1,100 mathematicians as well as a "Mathematicians of the Day" page which contains details of the mathematicians who were born or died on today's date.
Math Mistakes: "A site dedicated to the listing of mathematical mistakes made over and over by advertisers, the media, reporters, politicians, activists, and in general many non-math people."
MathNerds: Hints, suggestions, and references to help you figure out math problems.
The Math Tutor: Online help for free to students at all levels. Responses within 24 hours.
Mathematical Snippets: Wonderful graphic representations of mathematical concepts such as the Pythagorean Theorem and the Möbius Strip.
Paper Models of Polyhedra: Print out the patterns for a wide variety of three-dimensional geometric figures.
S.O.S. Mathematics: Your free resource for math review material from Algebra to Differential Equations.

Science

CELLS Alive!: This site has been recognized by professionals and kids alike as a wonderful source of graphic information on cells and bacteria. Find out how penicillin kills bacteria, for instance, and discover why some bacteria have become resistant to treatment.
DNA from the Beginning: "This site is organized around key concepts. The science behind each concept is explained by: animation, image gallery, video interviews, problems, biographies, and links."
The Endangerd Species Program: This site from the U.S. Fish and Wildlife Service is full of information about endangered species including lists of species endangered, information about recovering species, and lots of ways to get involved.
Environmental Diseases from A to Z: This presentation (one disease for each letter of the alphabet) gives basic information on environmental diseases for middle and high school students. Provides factsheets, pamphlets, a questions and answers section, and an extransive library of resources on the topic.
The eSkeletons Project: View the bones of the human anatomy from different angles and compare them with the bones of the gorilla, the orangutan, and the baboon.
Exploratorium: Come visit San Francisco's renowned science museum on the Web. Find dozens of online exhibits and do-it-yourself experiments.
Genetic Science Learning Center: "Helping people understand how genetics affects their lives and society." Presented by the University of Utah.
Inner Body: Explore human anatomy with this interactive site. (This site is graphics-intensive and requires a Java-enabled browser.)
Mad Sci Network: Created by scientists at Washington University Medical Schoolin St. Louis, this site has a wealth of useful information about biology, chemistry, and physics. Browse the MAD FAQS area or submit your own questions.
MicroWorlds: Explore the chemistry of materials by peeking at current research at California's Berkeley Lab's Advanced Light Source.
Monterey Bay E-Quarium: Electronic information about sea creatures and habitats from this Southern California aquarium. The site is particularly easy to use and navigate.
NASA's Welcome to the Planets: Look at pictures of bodies in our solar system as well as the spacecraft NASA has sent to explore them.
Nick Walker, the "Weather Dude": A weather page especially for kids, parents, and teachers from the Weather Channel forecaster Nick Walker.
The Nine Planets: A multimedia tour of our solar system.
WebElements Periodic Table (professional edition): Click on an element to get all its vital information. This site also has links to numerous other chemistry-related sites.
Physics 2000: From the University of Colorado at Boulder, this site uses interactive Java applets and cartoon characters to introduce physics in a friendly way.
Science Fair Central: The "Project Ideas" section has questions that can inspire even the most unmotivated students. A handbook tells students what a science project is and how to create an award-winning one.
Science Hobbyist: For students interested in science, this site offers cool science projects to do at home and explanations of science topics designed for high school students.
Science Learning Network: A science museum designed specifically for the Internet, this site is an endlessly diverting collection of exhibits, experiments, and discussions of science issues currently in the news.
ScienceMaster: Science news, information, links, columns, and homework help for students (6-12 graders) and their educators.
Scientists, Inventors, and Explorers: A large collection of links to biographical sources for scientists, explorers, and inventors. Browse in such categories as Indian Scientists, Nobel Prize Laureates, Weird Scientists, and Australian scientists.
Seeing, Hearing, and Smelling the World: From the Howard Hughes Medical Institute, this site explains how the brain sees, hears, and smells.
Space Calendar: Find out what happened and what will happen in space exploration on any date in 2004 through April 2005.
TheTech: The Tech is an exciting, hands-on museum of technology and an educational resource.
Thursday's Classroom: Classroom activities, reading, and projects based on current NASA research.
The Whole Frog Project: An online alternative to the messy dissection, this site uses MRI and 3-D images to provide a virtual tour of vertebrate anatomy.