Welcome to our exploration of stationary waves. A stationary wave, also known as a standing wave, is formed when two identical waves traveling in opposite directions interfere with each other. These waves must have the same frequency, amplitude, and wavelength to create the characteristic pattern we observe.
Now let's examine what happens when these two waves meet. This process is called superposition. When two waves overlap, their displacements add together at every point in the medium. We can see the individual waves in blue and red, and their combined effect shown in green as the resultant wave.
The stationary wave creates a distinctive pattern with two types of special points. Nodes are points that remain completely stationary with zero displacement at all times. These occur where the two waves always interfere destructively. Antinodes are points that oscillate with maximum amplitude, where the waves always interfere constructively.
In practice, stationary waves often form when a wave reflects from a boundary. Here we see an incident wave traveling toward a fixed boundary. When it reflects, the reflected wave travels back and interferes with the incoming wave, creating the stationary wave pattern we observed earlier.
To summarize what we have learned about stationary waves: They form when two identical waves traveling in opposite directions interfere through superposition. This creates a fixed pattern with nodes that remain stationary and antinodes that oscillate with maximum amplitude. This fundamental wave phenomenon appears in many practical applications from musical instruments to acoustic engineering.