When waves
meet.
In progress
Phase, interference, and superposition.
A quarter cycle apart.
The blue and orange waves have the same amplitude and frequency. The dark line adds their heights at each point. Drag across the diagram, or move the slider, to shift one wave relative to the other.
At 0°, their peaks and troughs line up: the combined amplitude doubles. At 180°, each peak meets a trough of equal size, and the sum is zero. At 360°, they line up again.
Relative phase determines whether the waves reinforce or cancel. Their individual amplitudes and frequencies remain unchanged.