Waves interfere when one wave passes through another.
Constructive interference: when a crest meets a crest or a trough meets a trough
The shape of the wave formed is determined by the sum of the seperate amplitudes of each wave.
Animation : http://zonalandeducation.com/mstm/physics/waves/interference/constructiveInterference/InterferenceExplanation2.html
Destructive interference: when a crest meets a trough.
The shape of wave formed is determined by the sum oftheamplitudes of each wave.
Since the postive amplitudes from one crest are added to the negative amplitudes from the other trough, the addition will look likea subtraction.
Animation: http://zonalandeducation.com/mstm/physics/waves/interference/destructiveInterference/InterferenceExplanation3.html
