As you see from my parents’ attire and the lack of leaves on the trees, these pictures are not brand new. But still interesting: Do you see how the waves are bent towards the coast as they run into shallower water?

And can you believe I still have to look up which one is refraction and which one is diffraction to make sure, despite having a PhD in oceanography? They really should consider retracting that. I am pretty sure I “was instructed” (avoiding to say “learned”, since I clearly didn’t) about this in a lab during first year physics. On the other hand, I know where to look it up. Does that count?

And maybe it’ll help if I write it down once more:

Diffraction is what happens to waves behind slits or obstacles.

Refraction is what happens when waves run into shallower/deeper water (or into a different medium if we are talking about light waves) due to dispersion.

Does anyone know a nice “Eselsbrücke”/mnemonic/way to remember?