http://howthingswork.virginia.edu/

http://www.nasa.gov/returntoflight/multimedia/index-how-it-works.html

http://www.howstuffworks.com/

http://howthingswork.virginia.edu/course.html

http://bible.cc/romans/8-28.htm

http://en.wikipedia.org/wiki/The_Way_Things_Work

http://en.wikibooks.org/wiki/Wikijunior_How_Things_Work/Refrigerator

http://www.etoys.com/genProduct.html?PID=4709707&ctid=29

http://www.libraryvideo.com/sm/twtw.asp

http://www.target.com/How-Things-Work-Books/b?ie=UTF8&node=3250

http://necsi.edu/publications/mtw

http://www.energyquest.ca.gov/how_it_works/index.html