An in-depth explanation of the Earth's water cycle, including a hyperlinked diagram that provides direct access to information about each phase in the cycle.

Extensive article that discusses the first principle of climate science, i.e., that the Sun is the primary energy source for the climate system of the Earth. Presents five concepts for this principle and explains each, providing...

The USGS gives an overview of the amount of water on Earth and where it is located. It gives a few interesting facts about the Earth's supply of water. Click Home to access the site in Spanish.