1-19. Constructive Interference
Figure 1-19. Constructive interference. Two positive pulses approach one another. When they meet both pull up on the string so that, at the time when they completely overlap, the maximum height is the sum of the heights of the two pulses. Then they move apart with the same shapes that they had originally.
Figure 1-20. Destructive interference. A positive and negative pulse approach one another. As they pass through one another, they cancel out temporarily, because their sum is zero at that time. Once they have passed one another, they move on without any change in their original shapes.
© William J. Mullin