Using graph paper, two waves were drawn, one under the other. Each possessed the same amplitude, frequency and wave length. The resultant wave which formed when they were both propagated at the same time was drawn to scale, based on the amplitudes of each wave overlapping. It was seen that the resultant amplitude was 2x the amplitude of each wave. The definition of constructive interference was given. The same procedure was done but with 2 waves in which the crests of one overlapped with the troughs of the second. The resultant wave was drawn and shown to be a straight line, a cancelling of each wave. The definition of destructive interference was elicited. A third resultant was drawn when 2 waves overlapped, but not precisely. This showed what occurs most of the time. The terms incident wave and reflected wave were defined based on sketches.