Tag: stratification

A ship that is continuously pulled with a constant force suddenly slows down, stops, and then continues sailing as if nothing ever happened? What’s going on there? We will investigate this in a tank! And in order to see what is going on, we have dyed some of the water pink. Can you spot what […]

Sometimes sitting in a café for a work meeting with #lieblingskollegin Julia can lead to unexpected discoveries of oceanographic processes — in my latte! It’s those little things that inspire blog posts… “Kitchen oceanography” brings the ocean to your house or class room! Oceanography is often taught in a highly theoretical way without much reference to […]

It’s pretty impressive when a mountain moves through a stratification and generates lee waves. But what I find even more impressive: The waves that travel behind the mountain when the mountain is long gone. See here: This kind of stuff looks more like a numerical simulation than something actually happening in a tank, doesn’t it? […]

The main reason why we went to all the trouble of setting up a quasi-continuous stratification to pull our mountain through instead of sticking to the 2 layer system we used before was that we were expecting to see a tilt of the axis of the propagating phase. We did some calculations of the Brunt-Väisälä […]

Did you guess what we needed the stratification for? Yes — we are moving mountains again! :-) What we want to look at: How a current reacts to an obstacle in its way, especially a current in a stratification. But since it is really difficult to set up a current in a tank, let alone […]

A wind stress is applied to the surface of a stratified and a non-stratified tank to cause mixing. This is a pretty impressive experiment to run if you have a lot of time, or to watch the time-lapse of if you don’t. The idea is that a density stratification will make mixing harder than it […]

My friends know me well. Especially A&I, which was proven again when they sent me the link to an article about two things that I am mildly obsessed with: Latte and double-diffusive mixing. My obsession with latte is a fairly recent thing, but I have been known to blog about interesting convection pattern in it […]

Even though most people think I am crazy, I always love watching the convection pattern develop in a hot drink.

Sometimes you actually see fresh water layers (see with your eyes, not a CTD or some other instrument) floating on top of denser waters, not only in your kitchen and with the help of dye, but for real. In this case, you see the layers because the shadow of a pole appears twice — once […]

How well do people understand hydrostatics? I am preparing a workshop for tomorrow night and I am getting very bored by the questions that I have been using to introduce clickers for quite a lot of workshops now. So I decided to use the hydrostatic paradox this time around. The first question is the standard […]

Last week we talked about misconceptions related to hydrostatic pressure, and how water always seeks its level. Today I’m gonna show you circumstances in which this is actually not the case! We take the fat separator jug we used last week. Today, it is filled with fresh water, to which we add very salty water through the jug’s […]

A wind stress is applied to the surface of a stratified and a non-stratified tank to cause mixing. This is an experiment that Martin and I ran at the JuniorAkademie this summer, but since I posted soooo much back than (just look for the tag “JuniorAkademie” to get an impression of what we did) I feel […]

Because I am getting sick of stratifications not working out the way I planned them. Creating stratifications, especially continuous stratifications, is a pain. Since I wanted a nice stratification for an experiment recently, I finally decided to do a literature search on how the professionals create their stratifications. And the one method that was mentioned over […]

A wind stress is applied to the surface to cause mixing. This is an experiment that I have been wanting to do for a long time, but somehow it never worked out before. But last night Martin and I finally ran it! We ran two experiments, one after the other. In the first one, we […]

Plus all kinds of dyes. (deutscher Text unten) Using the continuous salinity stratification created yesterday, Rolf and Daniel conducted a really cool experiment: They forced internal waves and watched them develop. I’ve converted their movie into a time-lapse; watch it below. Mit der kontinuierlichen Salzschichtung, die Daniel und Rolf gestern gebastelt haben, haben sie danach […]

Luckily I’m not the only one believing that we absolutely need remotely controlled boats! – Zum Glück bin ich nicht die Einzige, die findet, dass wir ferngesteuerte Boote brauchen! Mein Boot hat Hochkonjunktur. D. kann es in einem Tank wenden, der nur etwa 1.5 mal so breit ist wie das Boot lang! Das kann man […]

How to easily set up the stratification for the salt fingering process. Setting up stratifications in tanks is a pain. Of course there are sophisticated methods, but when you want to just quickly set something up in class (or in your own kitchen) you don’t necessarily want to go through the whole hassle of a […]

The “other” double-diffusive mixing process. After having talked extensively about double diffusive mixing in my courses, I tend to assume that students not only remember that there is such thing as double-diffusive mixing, but that they also remember our discussions on how the process works, and that they would be able to transfer this to processes […]

How to show my favorite oceanographic process in class, and why. As I mentioned in this post, I have used double-diffusive mixing extensively in my teaching. For several reasons: Firstly, I think that the process is just really cool (watch the movie in this post and tell me that it isn’t!!!) and that the experiments […]

On the coolest process in oceanography. My favorite oceanographic process, as all of my students and many of my acquaintances know, is double-diffusive mixing. Look at how awesome it is: Double-diffusive mixing happens because heat and salt’s molecular diffusion are very different: Heat diffuses about a factor 100 faster than salt. This can lead to […]

A tank experiment showing ship-generated internal waves. When entering a fjord from the open ocean by ship, it can sometimes be noted that the speed of the ship changes even though apparently nothing else changed – the wind didn’t change, the position of the sails didn’t change, the settings on the engine didn’t change – […]