Nodes have zero displacement; antinodes have maximum displacement

Wave Types, Polarisation & Stationary Waves — AQA A-Level Physics

Key Definition

Node — A point on a stationary wave where there is no vibration (zero displacement at all times).

Key Definition

Antinode — A point on a stationary wave where the vibration has maximum amplitude.

Nodes are fixed in position. Antinodes oscillate vertically but do not move along the string.
At nodes, destructive interference occurs (waves are in antiphase).
At antinodes, constructive interference occurs (waves are in phase).
Points between two adjacent nodes are all in phase with each other.
Points separated by an odd number of nodes are in antiphase.
Points separated by an even number of nodes are in phase.
The distance between adjacent nodes (or adjacent antinodes) is half a wavelengthThe minimum distance between two points on a wave that are in phase (e.g. crest to crest). Measured in metres (m)..

Examiner Tips and Tricks

Learn the definitions: $nodeA point on a stationary wave where the displacement is always zero. Located at half-wavelength intervals. = point$ of minimum or no disturbance; $antinodeA point on a stationary wave where the displacement is a maximum. Located midway between adjacent nodes. = point$ of maximum amplitudeThe maximum displacement of a point on a wave from its equilibrium (rest) position. Measured in metres (m)..
In exam questions, string lengths will be in whole or half wavelengths.