I don’t want to do the actual statistics, but it feels like most of what I post is completely dependent on people being able to see the images I post. Of course, that’s kind of the idea of the wave watching that I do: To show you waves the way you might encounter them, too, and then explain what you see.

But a foggy morning run and my dad’s recent eye surgery have made me think about accessibility of my blog posts, and that it must be extremely dissatisfying to just read / listen to a constant “See? And look here! See here?” without having any idea of what is going on.

In the image below, for example, you see Kiel fjord on a foggy morning, and it’s not really clear where the grey water changes into grey sky. The other shore can kind of be guessed in the right side of the picture, but all the landmarks that you would typically see, like the light house at Falckenstein or the Memorial thingy in Laboe, are swallowed up in the fog.

Or even more dramatic on the next picture: We see the sea front road on one side of the picture and the sea on the other, and both vanish into fog. The whole naval port is missing because it’s so foggy. There are two cars appearing out of the fog, and a cyclist about to be swallowed.

So I have decided that I need to work on my blog’s accessibility, and I am telling you this hoping that you will hold me accountable. And I am hoping for your input on this: I know that the alt text options on both blogs as well as Twitter and Instagram are there for accessibility reasons. But do people really use those, or would it be as helpful to write good figure captions going forward? Is using the same text in both the figure caption and alt text a good option or is that really annoying to people using a screen reader, because they now have to listen to it twice? What’s the best practice that you’ve seen?

For me, participating in the Science in Public conference was so inspiring! Not only because of the conference itself, but also because of the people I met there.

In a conversation about wave watching and how it can be done with kids, Felipe suggested to ask the kids to make wave models for them to discover waves with different senses and also build more defined mental models. Also these models could act well as conversation pieces to discuss different features that different kids might include.

I think he initially envisioned clay models, but I immediately saw the effect that would have on my flat (no! I cannot have every surface covered in clay wave models that I make or people give me!) and thought about sandpits instead. Easily available on most playgrounds, the “sculptures” don’t invite to be kept and stored, and also handling is very quick and easy.

So this morning, I set out to do a pilot.

Here is my first attempt of waves approaching the shore, getting steeper and steeper and finally breaking.

What this model doesn’t include, which I should really include next time, but this time I got chased away by tons of little kids: How the wave length gets shorter as the waves get higher.

Which you see, for example, when you look at waves that approach a shallow beach and get refracted towards it (see my model of that below).

Another phenomenon that worked really well in the sandpit: Interference of waves. Below you see the model (my feet for scale). Here I first made the horizontal lines just using my fingers, and then for the second wave field, I let some sand trickle through my fingers to have equal amounts of sand deposited over distance along the lines perpendicular to the first wave field.

And if you look at this from a smaller angle, you see that the areas where wave crests meet are highest — the typical interference pattern of waves.

But even with less effort, cool things can happen: See below my “ring waves radiating out from a point source” model.

This was definitely fun and actually a lot more educational than I would have expected, even for me as someone who has been thinking about waves a lot over the years. When representing wave fields, there are so many things to consider and you actually need to observe fairly carefully (or understand the physics really well) to be able to represent a snapshot of a moving water surface. So I see tons of potential here (especially since you don’t even have to do it in a sandpit, you could do it at the beach where you can observe waves simultaneously!), now I just need to figure out how I want to include it in a bigger concept. But such a cool idea, thanks Felipe!

What are you thinking about now? Do you want to start doing your scicomm in a sandpit, too? Any suggestions for me or ideas that might inspire new things?

At first glance, the picture above might not look too appealing. Dusty, almost stagnant water in a drainage ditch?

Ok, the dust might actually mainly be pollen, which makes it slightly better.

Oh, and it also provides us with insights about the flow in the channel! See, for example, how there seems to be a lot more flow in the channel going horizontally in the picture below than in the one that leads into that one? If the other one was carrying more water, there wouldn’t be a dirt streak going across its mouth, it would have deformed that streak in the direction of its flow.

Like all the stripes going across that horizontal channel: They are all deformed to show faster flow in the middle than to the sides, as we would expect for pipe flow, because there is more friction to the sides than in the middle.

See how the dirt collects on the left side of the picture? That’s because the flow then continues below surface level, so the surface films can’t easily go through the pipe with the flow. So we are collecting an archive of dust events here, almost like tree rings!

And these dirty smears on the far side of the channel? They are actually where blades of grass penetrate the water surface and thus modify the surface films. What you see as streaks are actually the wakes downstream of where the blades of grass break the surface!

The wriggly lines the grass draws into the surface film is caused by the grass being moved by the wind (Pity. It would be a lot more exciting if there was eddies in the water, causing these patterns. But unfortunately it’s really only the wind). But it does look pretty cool, doesn’t it?

Who would have known that looking into dirty drainage ditches would be so interesting?

You see them a lot here on Kiel fjord when it’s windy, and this is what they looked like last Saturday: Foam stripes than run parallel to the coast for as long as the coast is a sea wall (or at least something fairly straight). What’s going on there?

I have seen them over and over again, and the most common explanation that people have is Langmuir circulation, which i don’t actually think it is (and I show you some evidence for why I don’t think they are Langmuir circulation in this blog post). The stripes we see here are nowhere near parallel to the wind direction. Last Saturday, they were pretty much perpendicular.

So I think there is just a surface convergence there, parallel to the coast, probably related to the typical wavelength. So the question should probably be: Why is there a convergence parallel to the coast independent of the wind direction? What do you think?