http://www.howstuffworks.com/
http://pbskids.org/zoom/activities/sci/
http://www.edheads.org/
http://www.edheads.org/activities/simple-machines/index.htm
http://www.edheads.org/activities/weather/index.htm
http://www.edheads.org/activities/odd_machine/index.htm
http://www.msichicago.org/online-science/simple-machines/activities/simple-machines-1/
http://www.cclonline.com/pc/hardware/software/thecclgame/
http://www.hhmi.org/coolscience/
http://seasky.org/sky.html
http://seasky.org/sea.html
http://www.nineplanets.org/nineplanets.html
http://www.exploratorium.edu/ronh/weight/index
http://www.scienceworld.ca/fun_stuff/playstuff/bodyworksgames.html
http://www.scienceworld.ca/flash_games/lever.html
http://www.engagingscience.org/Activities/
http://kids.discovery.com/games/games.html
http://www.wsu.edu/DrUniverse/Contents.html
http://learnnowbc.ca/learningcentre/
http://billnye.com/
http://www.exploratorium.edu/explore/index.html