When two identical sound waves meet each other, the resulting phenomenon is known as interference. Interference can occur in two forms: constructive interference and destructive interference.
Constructive Interference: Constructive interference happens when two sound waves meet and their amplitudes (peak magnitudes) add up, resulting in a stronger combined wave. If the two waves are in phase, meaning their peaks and troughs align, they reinforce each other, leading to an increase in the overall amplitude. As a result, the sound appears louder or more intense at the location where the waves overlap.
Destructive Interference: Destructive interference occurs when two sound waves meet and their amplitudes cancel each other out. This happens when the waves are out of phase, meaning their peaks and troughs are misaligned. In such cases, the peak of one wave aligns with the trough of the other wave, leading to their amplitudes subtracting from each other. As a result, the combined wave has a lower overall amplitude or even no sound at all at the point of overlap.
The specific outcome of interference depends on the phase relationship between the two waves. If the waves are in phase, they reinforce each other, resulting in constructive interference. If they are out of phase, they cancel each other out, leading to destructive interference. In practice, interference can be observed in various scenarios, such as with overlapping sound waves from two speakers or when sound reflects off surfaces and interacts with each other.