This site contains a wide variety of educational resources for K12 educators including many links to help teachers with earth science topics addressed in the National Science Education Standards.
Provides over 150 links to teacher resources and student projects marked with appropriate grade levels for various topics including space, the atmosphere, soil composition, and much more.
Earth Trends: The Environmental Information Portal
Timely and accurate global environmental information through a searchable database with maps, country profiles, and much more is available on this site.