http://www.physics.umd.edu/lecdem/outreach/QOTW/qotwsubj.htm
http://www.physics.umd.edu/lecdem/services/demos/mainindex.htm
http://www.exploratorium.edu/snacks/
https://sites.google.com/site/winfailphysics/home
http://www.stmary.ws/highschool/physics/home/notes/default.htm
http://en.demo.phy.tw/
