It’s easier to watch this video in slow motion. Click the icon for Settings (a gear) and click “Speed.” Choose .25 (for quarter-speed) or .5 (for half-speed).
This video supplements “The Encyclopedia of Quantum Physics” at http://www.QuantumPhysicsLady.org/. Read on for description of what’s happening in this video.
Two waves approach each other, one from the right and one from the left. They meet in phase, that is, crest hits crest simultaneously. They move into a superposition, that is, they overlap each other. As they are also in phase, their crests reinforce each other and create a new higher crest.
Then, the waves continue traveling in opposite directions. They emerge out of superposition and resume their prior heights as if nothing had happened. The crests are back to what they were before the two waves went into superposition. (Of course, in real life, there would probably be some loss of energy.)
What would happen if the waves were completely out-of-phase–crest of one precisely hitting trough of the other? The superimposed wave would look completely flat, as if there were no wave present at all. Here’s what’s amazing–after the two waves emerged from the superposition, they would still resume their prior heights!
This is a remarkable aspect of wave behavior!
As a note, this can also be called “wave interference”–waves intercepting each other and either reinforcing each other or canceling each other.
For more articles like this go to “The Quantum Physics Encyclopedia” at http://www.QuantumPhysicsLady.org/.
[Animation by San Diego State University physics program http://sdsu-physics.org/physics180/physics180A/units/unit3/mechanical_waves.html.]