WAVE standing wave with labels

Image illustrating how a standing wave (black) is formed by the addition of a wave (green) and its reflection (red) inside an oscillator. Notice how at fixed points the standing wave has no amplitude. These points are called nodes and their positions are shown by fine grey vertical lines. Antinodes are the points of maximum amplitude or displacement. Standing waves like these are set up in musical instruments. For wind instruments, the waves represent compression rather than displacement.