Expedition learning

Last week, we ran an “expedition learning” course for 17-year olds. They were separated into several groups, working on different topics, and mine (unsurprisingly) worked on waves. You can see here what kind of stuff we observed when first testing the stretch of coastline we wanted to do our expedition to. And now you’ll get a picture dump of the actual expedition.

We started out in not-so-ideal-but-really-not-too-bad-either kind of weather, as you can read off the tracks below: It had been raining a little, but not very hard, and it had stopped by the time we got there.


The drift lines looked quite promising.


My group dove right into it (only figuratively, luckily, not literally). However I wasn’t quite sure if this guy knew what he was getting into?


At this point we were still very close to the car, so I thought that it might be quite smart strategically to let them figure out here how high the waders go and what happens if the waves are higher than the waders… And the wakes of two ships  meeting up at a headland are a very good place to learn about that kind of things!


This headland is a very good place to start observing waves in any case. Especially at the typical wind direction found here. Because then, looking back from the light house to the land, you see a large area that is sheltered where waves only build up gradually. Which is a very nice contrast to the waves arriving upwind and makes it very easy to observe differences.


And then if you look downwind from the headland, you see waves sneaking around the headland from both sides. Those coming from the right are from the fully developed wave field that has been growing all the way down Kiel fjord, and then those coming in from the left are the ones that only started growing downwind of the little barrier shown in the picture above.


Can you see it? Maybe easier on a panorama kind of picture?


Of course we always like to look at the ring waves that appear when other waves hit stones…


I didn’t foresee that wave watching would happen mostly from within the water, but the guys in my group made a good case for walking on the sand bank to actually measure the wave hight depending on the water depth (rather than just observing and estimating from dry land, as I would have done), but why not?


Luckily, they found the shallowest part of the sand bank in exactly the same spot I would have told them to look for it based on the wave field ;-)


Btw, a nice example of coastal dynamics right below. We had a coastal dynamics group, too, but I don’t even know if they looked at this kind of stuff, I mainly saw them taking soil samples.



And I know I made the same observation in the same spot last time, too, but I think it’s fascinating how the different directions of the ripples and drift lines and waves all come together.


In any case, a nice day at the beach!


Well, most of the time anyway.


Luckily, we found shelter!


Those, btw, are Annika and Jeannine, who were working with a different group on coastal vegetation.


But: New and interesting pattern on the beach once the rain was done!


The kids spent the next two days putting all their observations on maps and preparing a presentation, and I am really happy with how it turned out. Of course there is some room for improvement still, but how boring would it be if there wasn’t? ;-) All in all I think it was a pretty successful course!

Wakes and what they do to the sun’s reflection

When I said that wake watching made me happy last week, did you really think those were all the wakes I was going to show you? Ha! No, I have plenty more! :-)

Today, I want to show you a couple that have one thing in common: the way that they show up against the sun’s reflection and thus become a lot more visible than they would be if they were just reflecting a uniformly blue or grey sky.





Reflected wake

The best ship-watching of the year happens during Kiel Week (even if I do a fair bit of ship-watching year round ;-))

But this year, I was absolutely fascinated with wake-watching. Look at the sailing ship below and its beautiful wake!


You very clearly see the streak directly behind the boat, caused by turbulence where the hull pushed through the water. And then there is the actual wake, fanning out from the ship.


And then that wake gets reflected on a sea wall as the ship is sailing past!


Watching things like this makes me happy :-)

Duckies, a drama and a wake

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 :-)


When I was talking about foam stripes the other day, you might have noticed that the foam stripe wasn’t a foam stripe all the way, but became “just a stripe”. And since I have been thinking about surfactants a lot recently, I think that’s actually what we are seeing in places where the stripe is just a stripe: Some kind of film on the water.

Inside “the stripe” the water looks a lot smoother and waves are dampened out.

At first I thought that it was maybe due to being sheltered from the wind, but clearly that wasn’t the case. If anything, the stripe was in a location where it was more windy (see where it comes out underneath the pier? That should be funneling wind around that corner, not sheltering from the wind!). But surfactants would make sense if they collected in the convergence zone of the stripe.

See how the reflections from the sun are different where there is stuff on the water and the waves are dampened out?