Printhttp://www.physicsclassroom.com/Class/waves/u10l4a.cfm
http://en.wikipedia.org/wiki/Periodic_travelling_wave
http://www.ams.org/journals/bull/1942-48-08/S0002-9904-1942-07721-4/S000...
https://www.cis.rit.edu/class/simg303/Notes/Ch4-TravelingWaves.pdf
http://hyperphysics.phy-astr.gsu.edu/hbase/sound/trawvcon.html
http://hyperphysics.phy-astr.gsu.edu/hbase/waves/wavsol.html
http://web.utk.edu/~cnattras/Physics221Spring2013/modules/m10/traveling_...
6th grade
7th grade
11th grade
12th grade
