from class today

http://www.youtube.com/watch?v=rbKcXkvw1bg&feature=related

http://www.youtube.com/watch?v=-XGds2GAvGQ

Rubens tube and Chladni plates from earlier classes:

http://www.youtube.com/watch?v=cqilJNsiqig&feature=channel

http://www.youtube.com/watch?v=kBmRNkM9saA&feature=channel