Refraction applets, FYI

http://www.launc.tased.edu.au/online/sciences/physics/refrac.html

http://www.lon-capa.org/~mmp/kap25/Snell/app.htm

http://www.ndt-ed.org/EducationResources/CommunityCollege/Ultrasonics/Physics/refractionsnells.htm
(But note that the wave goes into a LESS dense medium, thus refracting AWAY from normal line.)

Enjoy!