Teaching Guidance for 14-16
Defining new terms: superposition and interference
From a teaching and learning point of view it is well worth the time and effort to introduce new terms carefully.
When two sets of waves interact and combine, the phenomenon is termed
superposition and the waves are said to
If the two sets of waves are directly in phase (or in step) at a certain point, the wave amplitudes add together and full
constructive interference occurs.
If the two sets of waves are directly out of phase (or out of step) at a certain point, the wave amplitudes cancel each other out and full
destructive interference occurs.
If two contributions superpose then there is interference.
Contributions out of step are out of phase: Superposition → destructive interference.
Contributions in step are in phase: Superposition → constructive interference.