Standing waves are caused by two waves interfering with each other, usually a wave and its reflection. A standing wave on a string is formed when the string length is a multiple of half wavelengths. The fundamental frequency is the lowest frequency at which a standing wave can form, which is equal to the wave speed divided by twice the string length. Harmonics are integer multiples of the fundamental frequency. Nodes are points that always have zero amplitude, while antinodes are points that have maximum amplitude.

1. Standing Waves A guide to what they are and where they are used

5. Let’s see one in action...