Other
Sea Sky: Explore the Sea
Climb aboard this submarine and explore the sea. This site has pictures and information about the oceans, coral reefs, as well as famous explorers of the deep. You can also play interactive games.
Other
Jungle Walk: Sponge Movies
Learn all you wanted to know about sponges. And see video clips as well as photos from The Sponge Reef Project, NOAA Ocean Explorer, National Geographic and more.
Center for Educational Technologies
Nasa: Classroom of the Future: Spheres: Hydrosphere
Use this site to learn about the millions and trillions of gallons of water that covers the earth, known as the hydrosphere.