Thin films
http://loganscheiner.elementfx.com/simulations/thin-film_interference/
See photons heating ground/air
http://mw.concord.org/nextgen/#interactives/physics/light-sound-physics/sunlight-infrared-physics
Resonance
Standing waves in a pipe
http://physics.bu.edu/~duffy/HTML5/longitudinal_standing_wave.html
See varying E and B fields
http://www.walter-fendt.de/html5/phen/electromagneticwave_en.htm
Resonance
Standing waves
Investigate inverse square law for radiation
http://www.thephysicsaviary.com/Physics/Programs/Labs/IntensityLab/index.html
Resonance
Standing waves