I had found some other videos that we can show to students in our lesson.
http://www.youtube.com/watch?v=ka7d-13iWbA&feature=player_embedded#t=58s
http://www.youtube.com/watch?v=52_mI88NY0w&feature=relmfu
http://www.youtube.com/watch?v=I-WKko4Y--M&feature=relmfu
http://www.youtube.com/watch?v=ga-GhSmn9EI&feature=player_embedded#t=1s