STANDING WAVES

Click on FORWARD below to start the animation. Note that the waves f(x,t) & g(x,t) are indentical in all respects.

Now check one of the boxes below so that you reverse the direction of one of the waves. Now they only differ in that f(x,t) is travelling one direction, while g(x,t) is travelling in the opposite direction. When the two waves interfere, their sum is a wave-like pattern that does not move -- a standing wave.

Two identical waves travelling in opposite directions and meeting is what you are likely to get in a system such as a guitar string in which any wave sent down the string will eventually reach the end of the string and reflect back upon itself.