Ask Numbers    Kidtopia

Dictionary.com   The Library of Congress
Digital Public Library of America   Making Science User-Friendly:
 Science Friday
Discovery Education   Merriam-Webster Dictionary
Exploratorium     National Geographic Kids
Fact Monster  S Science Fair Projects
Google Scholar   Scientific American
High School Ace     T The White House
I Infoplease: All the knowledge You Need Wikipedia – Free Encyclopedia
  International Children’s Digital Library iSeek