INTERFERENCE

Below are shown two waves that are identical in all respects except Amplitude. Click FORWARD. Note that the amplitudes of the two waves consistently add up to create a greater amplitude in the resultant wave. This is called constructive interference.

Now RESET the demo and make the phase shift for g(x,t) be 3.1416. Click FORWARD. Note that the amplitudes of the two waves consistently add up to create a lesser amplitude in the resultant wave. This is called destructive interference.

Finally, reverse the direction of one of the waves, and observe how you get constructive and destructive interference happening one right after another. In most situations where waves interfere there is both constructive and destructive interference occurring. Often interference occurs when the waves from a source (such as a TV transmitter) and the waves from a reflection of that source (such as off a building) meet.