The original double slit experiment 7:39 min video presented by Derek Muller of Veritasium in which he takes a cardboard box to the beach and demonstrates the wave nature of light to passers by. (Jnr Science, Phys 2.3, 3.3)
Sound interference illustrated with two speakers connected to a single signal generator.
Shows reflection with inversion for transverse and reflection for longitudinal pulses.
Diffraction and Interference of Water Waves
Photos of water waves at an Eastbourne beach showing diffraction and interference effects.
Wave properties such as interference are demonstrated with a tabletop wave tank, displayed using an overhead projector.