Destructive Interference

Wave pulses traveling in opposite directions with peaks on opposite sides of a wave demonstrator interfere destructively.

Discussion

When two wave pulses traveling on opposite sides of the wave demonstrator meet and pass each other, their displacements subtract, as predicted by the principle of superposition. This is an example of destructive interference. By stepping carefully through this movie during the period when the two pulses are passing each other, you can show that the amplitude, or maximum displacement, of the combined wave pulse at the point of maximum overlap is equal to the difference of the amplitudes of the two single pulses.