The various accessories allow different wave effects to be studied. Strobe illumination gives the best results at all frequencies. Higher frequencies give shorter wavelengths with the waves closer together. Since the patterns are stationary a sheet of tracing paper or OHP film can be placed on the viewing screen and drawings made for subsequent analysis.
Observe the incident and reflected wave directions from plane waves. Vary the plate angle to see the effect. Circular waves and the reflection of these can also be studied.
Plane wave diffract around and behind the plate. If two plates are used with a narrow gap between them, circular waves can be seen.
Use the twin point dipper with nothing else in the tank. Constructive and destructive interference will be seen where the two sets of circular waves meet.
Refraction relies on the different speeds of water waves in different depths of water. As the waves slow down in the shallow water they bend round slightly towards the normal. With a single point dipper, the distortion of the circular wave pattern is very obvious. With a convex lens shape the plane waves create a focusing effect. With a concave shape and plane waves there is a divergence of the waves as they pass over the shape.