INTERFERENCE - STANDING WAVES IN 1 DIMENSION

When two identical waves pass in opposite directions, they interfere with each other. The total height at any time is the vector sum of their individual heights.

TRANSVERSE WAVES are by far the easiest to visualise.

Believe it or not, the diagrams above represent two transverse waves, one blue, the other green passing through each other.

Each picture is taken at a quarter period when each wave has moved a quarter wavelength starting with them exactly in phase.

Only four pictures are needed as the whole thing repeats at t = 4T/4. The purple wave is the resulting standing wave.

LONGITUDINAL STANDING WAVES

These are again the hardest to visualise.

These waves types are particularly important in sound.