Constructive interference
The surface displacement equals the sum of all waves. When crests (or troughs) align, the resulting height
momentarily equals the sum of their heights before they continue propagating independently.
Destructive interference
Two equal-amplitude waves 180° out of phase cancel: crest meets trough → near-zero net displacement.
Standing wave
Two equal waves traveling in opposite directions form nodes (no motion) and antinodes (max motion).
Spring–neap (beats)
Slightly different frequencies (or wavelengths) produce slow amplitude modulation: alternating large
(“spring”) and small (“neap”) envelopes.
Dispersion
In deep water, phase speed increases with wavelength. Here we constrain speed ∝ √λ for all waves; adjusting λ
updates speed automatically.