More sites to try:

www.howstuffworks.com   Great videos and explanations on almost any topic!

www.edheads.org  Use this site to understand simple machines-lots of interactive games to play too.

http://interactivescienceteacher.com Find lots of interactive games on a variety of science topics.

http://school.discoveryeducation.com  Who doesn't love the Discovery channel?  Science, nature and more-explore it here!

www.nova.org  The ultimate in science stuff!

These are really cool too!:

www.exploratorium.edu/traits/cell_explorer.html  Biology students-you will find everything you need to know about cells and their function at this site.

www.chemicool.com  This site explains the periodic table, detailing each element.

www.webelements.com  Another site that explains the periodic table.

www,crimeandclues.com  Do you enjoy forensic science and solving crimes-check out this site!

www.csitheexperience.org  Experience CSI-go to the link: You Can Crack the Case-and solve a crime in CSI-tyle.

www.montereybayaquarium.org  Ocean creatures are calling-stunning pictures of sea creatures.
 
www.bbc.co.uk/sn/ 

www.nationalgeographic.com  This site is incredible!  You have to take a look...