4 links
Basic Science for Kids
sciencemadesimple.com
Contains science projects and experiments for kids, along with detailed answers to science questions and unit conversions.
MadSciNet: The 24-Hour Exploding Laboratory
madsci.org
Utilize a random knowledge generator and find out what's cooking up in a Mad Scientists' section.
Science Quiz Activities and Games
syvum.com
Collection of interactive quizzes for students in grades 5-9.
ScienceBob.com
sciencebob.com
Enter the world of Science Bob to try home experiments, visit his online lab, and get answers to general science questions.