Waves & Optics · Physics

When waves overlap, the result is their sum.

Superposition is the rule behind interference patterns, beats, and standing waves. Learn how to add waves cleanly and interpret what the sum means.

This topic

Superposition Principle

Add waves point-by-point, then use phase to predict constructive and destructive interference.

Rule

Linear superposition of waves

In linear media, overlapping disturbances add. This is not a “special trick”—it is the defining feature that makes wave analysis manageable.

Pattern

Constructive interference

Constructive interference happens when waves arrive in phase, reinforcing the disturbance and producing larger amplitude.

Pattern

Destructive interference

Destructive interference happens when waves arrive out of phase, reducing or even canceling the disturbance locally.

Pulses

Wave pulses and overlap

Pulses add while overlapping, then continue onward. This is the cleanest way to see superposition without requiring sinusoidal formulas.

Practice

Practice & Exercises

Practice adding wave shapes, using phase to predict outcomes, and interpreting superposition on graphs.