Category Archives: observation

Refraction of waves towards the beach

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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?

Playing with a thermal imaging camera

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Today I’ve been playing with a thermal imaging camera. Below you see a snapshot of my experimental setup, but before I tell you more about that experiment, a little bit of playing around.

See my reflection in my porthole below? (Btw, how awesome is it that I found a porthole to decorate my living room with???)

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That reflection also shows up with the thermal imaging camera.

And since I was taking pictures of myself: Here I am with “ice-cube make-up” and glasses that I had taken off for a while and then picked up again just before taking that picture. Do you see the endless possibilities of playing with a thermal imaging camera?

Shallow water waves

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Have you ever noticed how, if you are at a shallow beach, no matter how choppy waves are further offshore, everything becomes nice and orderly on the beach?

Below you see where the water depth suddenly increases, both from the color of the water and from the wave pattern. While in deeper water waves propagate at all kinds of speeds depending on their wavelength, the moment the water becomes shallow enough, all waves propagate at the same speed (except for the really short waves for which the water is still deep, but let’s forget about those). If all waves propagate at the same speed, it means that the form of the wave that we observe stays constant over time and just moves as a whole. Hence it looks a lot more tidy than the choppy waves further out.

Funny that in all these years of wave watching, I have never thought about that before!

Watch the movie below to see for yourself

Duckies, a drama and a wake

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Let me tell you the story of the picture below. I was walking along Kiel fjord with some friends and we saw this mama duck with all those tiny cute ducklings. We stopped and oooo’d and aaaaa’d and they were just so adorable!! But the after a while they swam on and we continued walking. But then there were people standing on the sea wall, obviously very worried about something. And then we saw it: a tiny duckling that had gotten separated from its family! It was struggling so hard to catch up with the rest, but they were swimming together while the little one was trying to climb over the rocks along the sea wall! The distance grew larger and larger. People started cursing mama duck for leaving the little one, or were pleading with her to come back for the poor baby. And then mama duck started heading out into the open fjord, where it was a lot more windy and wavy. How should the poor baby ever catch up? Eventually mama duck turned back. But she didn’t spot the baby! They all swam in the wrong direction away from the baby! It was dramatic. The crowd on the promenade was agitated. People were heading towards the ladders to climb down and rescue the baby! Then, finally, mama duck and all the siblings came back. Baby duck sprinted back to its family and finally everybody was reunited. Phew! The crowd wasn’t quiet ready to leave, not quite trusting mama duck that she wouldn’t abandon baby duck again. But then we decided that we had seen the happy ending, the scar hadn’t hurt for 20 years and all was well.

The reason I am telling you this story? Because I am still fascinated by wakes of ducks. And I saw really beautiful ones this morning:

The structure inside of the legs of the V is clearly visible.

And what’s even better: you can see the pattern on the sea floor, too!

The more I observe waves, the better I get at noticing details that were probably always there but that never stood out to me as clearly as they do now.

That’s why I am so happy about having started this blog — it helps me observe so many amazing things :-)

Oh, and if you are still waiting for the wake? Sorry, this was it. I was obviously talking about waves :-)