Beats occur when two waves with slightly different frequencies interfere. The beat frequency is the absolute difference between the two frequencies: |f1 - f2|.

Standing waves are formed by the superposition of two waves with the same frequency, amplitude, and wavelength traveling in opposite directions. This results in fixed nodes and antinodes.

The possible wavelengths of a standing wave are determined by the size of the region to which it is confined. For a string of length L fixed at both ends, the wavelengths are given by $\lambda_n = \frac{2L}{n}$, where n is an integer (1, 2, 3, ...).

The phenomenon where two or more waves overlap, resulting in a combined wave whose displacement is the sum of the individual waves' displacements.

The interaction of two or more waves that results in either reinforcement (constructive interference) or cancellation (destructive interference) of the waves' amplitudes.

Periodic variations in amplitude resulting from the superposition of two waves with slightly different frequencies.

A wave pattern created when two waves of equal frequency and amplitude travel in opposite directions and interfere, resulting in fixed points of maximum and minimum displacement.

Points along a standing wave where the amplitude is at a minimum (ideally zero).

Points along a standing wave where the amplitude is at a maximum.

Harmonics are multiples of the fundamental frequency of a wave. They are also known as overtones and contribute to the timbre of a sound.

The distance between two consecutive nodes is half of the wavelength ($\lambda/2$).

The distance between two consecutive antinodes is half of the wavelength ($\lambda/2$).