Constructive and Deconstructive Waves

 Constructive Interference is when waves ADD or BUILD. The waves are on the SAME SIDE.

Deconstructive Interference is when waves SUBTRACT or CANCEL each other (temporarily until they're no longer overlapping). The waves are on OPPOSITE SIDES.

You can also have interference with standing waves. Look to see how they're "in sync" or "out of sync" and how that makes them add to be bigger or cancel to be smaller.

Examples:

A (+2) + (+3) wave = +5 wave

A (-2) + (+3) wave = +1 wave

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