Some science websites
http://www.sheppardsoftware.com/science.htm
http://www.pbs.org/parents/education/science/games/first-second/
http://www.wartgames.com/themes/science/simplemachines.html
http://www.mikids.com/Smachines.htm
http://www.softschools.com/science/
https://www.brainpop.com/games/