## Periodic Wave Overlap

The overlap of two periodic waves occurs analogously to the overlap of pulses.

Causing a resulting wave with elongation points equivalent to the algebraic sum of the overlapping wave points.

The figure above shows the overlap of two waves with equal periods and different amplitudes (I and II), which, when overlapped, results in a wave with amplitude equivalent to its waves (III). This is an example of constructive interference.

This other example shows a destructive interference of two waves of the same frequency and amplitude, but in phase opposition (I and II) which, when overlapping, results in a wave with zero amplitude (III).

The prime examples of overlapping waves are wave ripple phenomena and standing waves.

- Beat: Occurs when two periodic waves of different frequency and same amplitude overlap, resulting in a wave with varying amplitudes dependent on the sum of amplitudes in each resulting crest.
- Standing waves: This is the phenomenon that occurs when two waves overlap with the same frequency, speed and wavelength, in the same direction but in opposite directions.