Other
University of Texas at Dallas: Why Is the Sea Salty?
A clear and concise explanation of why some of the earth's waters are salty and others are not.
US Geological Survey
Usgs: All of Earth's Water in a Single Sphere!
See how all of Earth's water compares to the total size of the Earth.
PBS
Nh Pbs: Nature Works: Estuaries
Learn more about estuaries when you visit this informative site. This resource provides locations of and weblinks to estuaries in the United States.
Science4Fun
Science4 Fun: Lakes
What is a lake? Learn about some famous lakes in the world and how they are formed.
Bill Nye
Bill Nye: Eggs Speriment
Try this at-home science experiment to learn if salt affects the way things float.