• Kinetic, potential energy and thermal energy, tuning forks, amplitude, and frequency
  
• Spaced Out: A Cosmic Scene Episode 1, Wave if You Got Energy
  
• Lesson ideas on electromagnetic spectrum – waves of energy
  http://school.discoveryeducation.com/lessonplans/activities/electromagneticspectrum/#aca
  
• Electromagnetic waves – has an applet to show different frequencies and explains what a wave is:
  http://www.colorado.edu/physics/2000/waves_particles/index.html
  
• The nature of a wave – with animations
  http://www.physicsclassroom.com/Class/waves/U10L1a.cfm