The amplitude of a standing wave can vary along the length of the wave. This is because a standing wave is formed by the superposition of two waves traveling in opposite directions, known as the incident and reflected waves. These waves interfere with each other constructively and destructively, creating regions of maximum and minimum amplitudes, called nodes and antinodes, respectively.
The nodes are points along the wave where the displacement of the particles is always zero. At these points, the two waves interfere destructively, resulting in the cancellation of amplitudes. Therefore, the amplitude is minimum or zero at the nodes.
On the other hand, the antinodes are points of maximum displacement. At these points, the two waves interfere constructively, resulting in the reinforcement of amplitudes. Therefore, the amplitude is maximum at the antinodes.
As a result of this interference pattern, the amplitude of a standing wave varies spatially. It oscillates between zero at the nodes and maximum at the antinodes. This variation in amplitude is a characteristic feature of standing waves and is distinct from traveling waves, where the amplitude remains constant as the wave propagates.