NASA for middle-school students http://www.nasa.gov/audience/forstudents/5-8/features/index.html
National Geographic for Kids http://www.nationalgeographic.com/kids/
World Biomes http://www.blueplanetbiomes.org/world_biomes.htm
Up-to-the-minute Seismic Activity Around the World http://www.iris.edu/seismon/
Roller Coaster Physics http://www.funderstanding.com/k12/coaster/
Periodic Table Information http://www.chemicalelements.com/
Rock Information http://geology.com/rocks/
Rock Description Table http://geology.about.com/library/bl/blrockident_tables.htm