Links
1. "Beats" is a page with a java applet that demonstrates beats. It also has a good definition of beats. http://www.slac.stanford.edu/~ohnemus/Toys/beats.html
2. This site is another page with a java applet demonstrating how beats work. http://lectureonline.cl.msu.edu/~mmp/applist/beats/b.htm
3. This page has links to many resources concerning many topics of physics including light and sound. http://alpha.sd41.bc.ca/departments/sciences/physics/
4. This site contains a java applet that explains how longitudinal waves work. http://members.xoom.com/Surendranath/Lwave/Lwave01.html
5. This site talks about constructive and destructive interference. http://einstein.byu.edu/~masong/HTMstuff/C13A1.html
6. This site has several experiments on wave interference. http://www.colorado.edu/physics/2000/schroedinger/index.html
7. This is another site about interference. http://csgrad.cs.vt.edu/~chin/interference.html
8. This is a site about energy carried by waves and interference. http://www.cen.bris.ac.uk/students/eqteach97/waves5.htm
9. "Light" is a page about the history of light. http://www.mustsee.co.il/hebrew/yeda2000/light/light.htm
