Wave InterferenceWhen two waves or pave pulses are in the same place at the same time, they interfere with one another. There are two possibilities: Constructive interference and destructive interference.
In this demonstration, the red pulse and the blue pulse combine to make the yellow interference pattern. Notice that the two pulses are unaffected by the interaction and continue moving in their original directions.
The disturbance shown in red color is due to a source somewhere beyond the left end. The disturbance shown in white is due to a source somewhere beyond the right end. The resultant disturbance is shown in yellow color.
Change the phase from in to out, click stop, and use the slider at the bottom right of the screen to align the white and red pulses in the same place. What does the interference pattern look like?
If two dimensional waves—like sound waves—interfere, it is a little more complicated. Areas of constructive and destructive interference are spread around in space. This makes loud spots and quiet spots.
In the following demonstration:
Click on the "Two Source Interference" tab at the top.
Click on audio enabled, and make sure that the volume on your computer is on at a reasonable level.
Use the mouse to move the man around the screen.
What happens to the sound as you move the listener around?
