Waves
Standing Waves - shows open and closed pipes and the difference between displacement and pressure graphs
Huygens Principle - explaining reflection and refraction using Hugen's Principle
Standing Waves on a string - shows what it says plus more than one harmonic at a time
Formation of standing waves - as it says
Geometric Optics - perfect for a basic introduction to lenses and then the detail of a ray diagram
SHM and oscillations - perfect for sixth form. Created by Salford UniversityDoppler
Doppler Explained - some nice animations from the school of Physics, Sydney, Australia
Geometric Optics - from Phet