(Sample link) NASA for middle-school students http://www.nasa.gov/audience/forstudents/5-8/features/index.html
(Sample link) National Geographic for Kids http://www.nationalgeographic.com/kids/
On-line Student Textbook for The American Journey http://glencoe.mcgraw-hill.com/sites/0078693861/
on-line student textbook for the American Journey http://www.glencoe.com/sec/socialstudies/ose/disc_our_past/ca/2006/journey_wwi/swopen.pdf