NSTA - National Science Teachers Association
ENC - Eisenhower National Clearinghouse for Math and Science

BrainPop - Original animated movies that explain science, biology and technology topics.

Matter
Atoms Movie from BrainPop - Download a movie and learn all about atoms. Take the online quiz.
The Discovery of the Electron - Learn about the experiments of J.J.Thomson and the discovery of the electron.
Chem4Kids - Everything explained from atoms to elements to the periodic table.
Chemical Elements - An online, interactive Periodic Table of the Elements.

Electricity
Beakman's Electric Motor - Simple directions on how to make an electric motor out of ordinary household items.
Electricity Movie from BrainPop - Download a movie and learn all about electricity. Take the electricity quiz.

Digestion
Digestion Movie from BrainPop - Download a movie and learn all about digestion. Take the online quiz.

Photosynthesis
Photosynthesis - A simple explanation with a diagram.

Biomes
Biomes of the World - explore the 6 biomes of the world...location, basic facts, plants/animals, images.

Solar System
Solar System in 3D Images
A Field Guide to the Universe - Explore the planets in our solar system, visit with famous astronomers, or probe into our spacecraft, past and present, in this interactive field guide to our universe.
Star Child: The Solar System - Learn about thal Deal on the Digestive System e sun, moon, planets, and other objects in our solar system.
NASA Kids - The Solar System - Explore the solar system. Then find your age and weight on other planets!
California Institute of Technology: Welcome to the Planets - Take an up-close look at the planets.
Natural Geographic Society: Virtual Solar System - Take a virtual tour of our solar system.