Constructive Interference: occurs when 2 of the same type of wave (either upper or lower) from opposite sources meet and the energies from both waves combine to increase the amplitude (energies are additive) for a split second before continuing on through the medium as normal
Destructive Interference: occurs when 2 “out of phase” waves (both a crest and a trough) from opposite sources meet and the energies of both waves cancels out at equilibrium (as the energies work against each other) for a split second before continuing on through the medium as normal
How Do Noise Cancelling Headphones Work?
Noise Cancelling Headphones work by producing destructive interference sound waves that are “out of phase” with oncoming noise to cancel out the sound before it reaches the listener’s ear.