Movie on wave interference – two wave fields arriving perpendicular to each other, interacting and leaving.
When talking about waves, it is often difficult to explain that wave heights of different components of a wave field can be added to each other to give a resulting wave field, but that each of those components continues to travel with its own direction and speed and comes out of the wave field basically unaltered. Students learn about constructive, destructive and complex interference (see image below), but it is hard to realize that those interactions are only momentary.
When I was on my way up to Isafjördur to teach CMM31, my friend Astrid and I happened to find the perfect example for the phenomenon described above. We were in Gardur in southwest Iceland and took a sunset walk to the lighthouse.
The lighthouse is located at the end of a pier and we observed a spectacular wave field. Two distinct fields were meeting each other at an almost 90 degree angle, interacted and left on the other side still clearly recognizable.
The waves met, interacted, and left the area of interaction. Watch the movie below to get an impression!