- https://phet.colorado.edu/en/simulation/sound
- sound intensity phet
- https://www.iknowthat.com/ScienceIllustrations/sound/science_desk.swf
- Different size wine glasses with difference frequencies
- https://www.cabrillo.edu/~jmccullough/Applets/Flash/Fluids,%20Oscillation...
- How sound travels through air. Shows a 1D and 2D graph side by side.
- https://physics.bu.edu/~duffy/HTML5/longitudinalwave.html
- Pretty cool longitudinal wave sim