![[annotated photo] Photo of water flowing over a weir, annotated with arrows showing particle velocities](https://mirjamglessmer.com/wp-content/uploads/2020/12/FotG-300x168.jpg)
Testing the new particle tracking app “Flow on the Go”
The new particle tracking app “Flow on the Go” became available for testing on iOS yesterday. And it is SO AWESOME!!! The idea is that particle that are advected in…
Category: demonstration (difficult)
Artikel “Praxisnähe dank digitaler Versuchsküche” von P. Mertsching über remote #KitchenOceanography
Im “eMagazin für aktuelle Themen der Hochschuldidaktik” der Uni Kiel ist der Artikel “Praxisnähe dank digitaler Versuchsküche” von Phil Mertsching über Torge’s und mein Projekt “Dry Theory 2 Juicy Reality”, insbesondere…
Collaborative Taylor column experiments during lockdown
We’ve become quite experienced with remotely-controlled rotating tank experiments, but the current lockdown brought us into yet another new-to-us situation: We had plans to film and live-stream tank experiments from…
Taylor column in rheoscopic fluid
I have a slightly complicated history with Taylor column experiments — even though the experiments look fine compared to all other videos I’ve found online, I somehow always had higher expectations.…
Tilting frontal surface under rotation / cylinder collapse
Torge and I are planning to run the “tilting of a frontal surface under rotation / cylinder collapse” experiment as “remote kitchen oceanography” in his class on Thursday, so I’ve…
A common misconception in rotating tank experiments, and one way of maybe not reinforcing it
A very common misconception when looking at atmosphere & ocean dynamics in a rotating tank is that the center of the tank represents one of the poles and the edge…
Solid body rotation
Several of my friends were planning on teaching with DIYnamics rotating tables right now. Unfortunately, that’s currently impossible. Fortunately, though, I have one at home and enjoy playing with it enough…
New rotating table on #FlumeFriday! Welcome to the family!
In addition to our four DIYnamics-inspired rotating tanks, we now have a highly professional rotating table with SO MANY options! And also so much unboxing and constructing and trouble-shooting to…
Rotating tank experiments on a cone
I had so much fun playing with rotating tank experiments on a cone this afternoon! And with Torge Martin (who I have the awesome #DryTheory2JuicyReality project with) and Rolf Käse…
Nansen’s dead water explained on YouTube
Remember the experiment on Nansen’s observation of “dead water” that Elin & myself set up as part of GEOF213? Our movies of this experiment are now featured in a brilliant…
Taylor column
I was super keen on trying the Taylor column experiment, but maybe I expected things to look too much like my sketch below, or my technique isn’t quite perfect yet,…
Topographic Rossby waves in a tank
This experiment just doesn’t want to be filmed by me. Even though I spent more time on preparation of this experiment than on almost any other experiment I have ever…
Topographic Rossby wave
Next attempt at the topographic Rossby wave! This time with following the geosci.uchicago.edu instructions more closely… …and then the tank had hickups, so we did get waves, but a lot more…
Planetary Rossby waves
I ran my new favourite experiment again, the planetary Rossby waves. They work super well on the DIYnamics table we built in Kiel and they also worked really well the other…
Planetary Rossby waves filmed with co-rotating camera
And here is my new favourite experiment again: Planetary Rossby waves! This time filmed with a co-rotating camera. We have a square tank with a sloping bottom at solid body…
Topographic Rossby wave
Finally trying the topographic Rossby wave experiment I wrote about theoretically here! And it is working — ok-ish. If you know what you are looking for, you can kind of…
Taylor column in a rotating tank
For both of my tank experiment projects, in Bergen and in Kiel, we want to develop a Taylor column demonstration. So here are my notes on the setup we are…
Rossby waves in a rotating tank — three different demonstrations
For both of my tank experiment projects, in Bergen and in Kiel, we want to develop a Rossby wave demonstration. So here are my notes on three setups we are…
Spin down — lots of shear instabilities in our tank!
When you stop a rotating tank, lots of stuff happens and it is usually very impressive to watch. Sometimes we stop tanks on purpose to show for example the development…
Parabolic surface shape of a tank of water in solid body rotation
One of the first exercises Torge and I plan on doing with the students in our “dry theory to juicy reality” project is to bring a water-filled tank to solid body…
Rotating vs non-rotating turbulence — now with movie!
Lots of demonstrations being prepared for Torge’s and my “dry theory to juicy reality” project. Shown here today: rotating vs non-rotating turbulence. Because the only way to really appreciate how…
Spinning dye curtain — when a tank full of water has not reached solid body rotation yet
With all the rotating tank experiments I’ve been showing lately, one thing that comes up over and over again is the issue of solid body rotation. On our DIYnamics-inspired turntable for…
Baroclinic instabilities / Hadley cell circulation in a tank
The DIYnamics-inspired turntable that Torge and myself have been working on for our “dry theory to juicy reality” project is finally working well! This is what the setup now looks…
Combining rotation of a water tank with a temperature gradient: A Hadley cell circulation demo!
Yesterday, we combined a thermally-driven overturning circulation with the effects of rotation, and thus created a Hadley cell circulation. And while the tank was turning faster than we would have…
Combining a slowly rotating water tank with a temperature gradient: A thermal wind demonstration!
Setting up an overturning circulation in a tank is easy, and also interpreting the observations is fairly straightforward. Just by introducing cooling on one side of a rectangular tank a…
Why do we need a rotating tank to study ocean and atmosphere dynamics? A demonstration
For our project “Ocean currents in a tank: From dry theory to juicy reality“, Torge, Joke and I are working on building affordable rotating tanks to use in Torge’s Bachelor…
Demonstrating Ekman layers in a rotating tank: High pressure and low pressure systems!
Ekman spirals — current profiles that rotate their direction over depth, caused by friction and Coriolis force — are really neat to observe in a rotating tank. I just found…
Working on our own affordable rotating table for oceanographic experiments!
Inspired by the article “Affordable Rotating Fluid Demonstrations for Geoscience Education: the DIYnamics Project” by the Hill et al. (2018), Joke, Torge and I have been wanting to build an affordable…
Supporting conceptual understanding of the Coriolis force through laboratory experiments
My friend Pierré and I started working on this article when both of us were still working at the Geophysical Institute in Bergen. It took forever to get published, mainly…
Tank demonstration of the circulation in a fjord
It has been a long time in the making, but finally we have a nice fjord circulation in our tank! Pierre and I tried to improve it 6 years ago,…
Need your help! “Wish list” for a student lab for tank experiments?
I’d love your input: If your student lab for GFD tank experiments had to downsize, but you had to present a “wish list” for a smaller replacement, what would be…
Lee waves with an asymmetrical “mountain”
How will lee waves look differently if we are using the asymmetrical mountain instead of the symmetric one? And is symmetry actually important at all or are we just looking…
Instructions: Dead water demonstration in the GFI basement
This blog post is meant as guidelines if someone other than me might have to set up this demonstration at some point… Have fun! :-) Setting up the stratification If…
Instructions: Lee wave demonstration in the GFI basement
This blog post is meant as guideline if someone other than me might have to set up this demonstration at some point… Have fun! :-) Lee waves Lee waves are…
Demonstration: Nansen’s “dead water” in a tank!
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…
Accidental double-diffusive mixing
When setting up the stratification for the Nansen “dead water” demo (that we’ll show later today, and until then I am not allowed to share any videos, sorry!), I went…
Please discuss: Experimental setup for Nansen’s “dead water”
During my last visit to Bergen in August, we set up a nice “dead water” experiment. However, there are nice experiments, and then there are awesome experiments, and since Elin…
Waves in a density stratification. One of the most beautiful tank experiments I’ve ever seen.
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…
Dead water — the fancy experiment including Nansen himself
Now that we do have a really awesome 12-layer 6-color stratification, we obviously had to do the dead water experiment again. This time we chose to include a not-too-happy-looking Nansen…
“Coriolis fountain”
We’ve been thinking about Coriolis deflection a lot recently (see links at the end of this post). But this weekend, at Phaenomenta Flensburg, I came across a so-called “Coriolis fountain”.…
Fictitious forces (3/5): Coriolis force — how we think it should be taught
So how do we teach about the Coriolis force? The following is a shortened version of an article that Pierre de Wet and I wrote when I was still in…
Pressure distribution on a wing
Another neat experiment in the collection I’ve recently been talking about is measuring pressure at different points on a wing profile. It’s not terribly surprising that – as long as…
Pitot tube
Another one of those awesome hydrodynamics toys: A Pitot tube! This is what it looks like: What you can’t see here is the little hole at the tip of the…
Playing with Venturi tubes II
On Monday I posted about playing with Venturi tubes. Guess what: We are going to play more today! Because today the Venturi tubes are connected to a “proper” manometer: Now,…
Playing with Venturi tubes
A Venturi tube is one of the things one hears about in hydrodynamics class all the time, but one never gets to see them for real. And even though I…
Flow direction reversing downstream of obstacle
One of the things that fascinated me most when playing with the huge fan we used to look at the flow downstream of a paddle was how the flow direction reverses.…
Flow around obstacles
We’ve played with the flow around a paddle recently, and you didn’t really believe I stopped there, did you? Of course I didn’t! But I have many many hours of…
Visualizing flow around a paddle
Whenever I’m in a canoe or kayak, I love watching the two eddies that form behind the paddle when you pull it through the water. It looks kinda like this:…
Wave fields around objects in a channel
One of the reasons I have been wanting to do the vortex street experiment I wrote about on Monday is that it is pretty difficult to visualize flow fields (especially if…
Standing waves in a tank
And really high order ones, too! On Monday, I showed you a movie on wave generation in Hamburg Ship Model Basin (HSVA)’s wave tank. At the end of that movie, we…
Stokes drift
When a higher-order effect suddenly becomes important. During our excursion to Hamburg Ship Model Basin (HSVA), one of the experiments we ran was on Stokes drift. You can already see in that post’s…
Wave tank
Excursion to Hamburg Ship Model Basin. I recently got to join a class on their excursion to Hamburg Ship Model Basin (HSVA, “Hamburgische Schiffbau-Versuchsanstalt” klingt so viel besser!). Those are amazing facilities…
Influence of stratification on mixing
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…
The effects of rotation on a collapsing column
Comparing a rotating and non-rotating dipole. I just realized that I never explicitly showed the difference between rotation and no rotation, even though I do have the footage to do so:…
Simulations of hetonic explosions
Because sometimes it’s easier to control a computer than rotation, salinity, water and dye. After looking at a non-rotating cylinder collapse the other day, it is time to look at…
Collapsing column
Or: This is what happens to a hetonic explosion experiment without rotation. I’ve posted a lot while at JuniorAkademie a while back, so it is hard to believe there are still experiments…
Cylinder collapse on a cone
Water running uphill during spin-down – how much more awesome can it get? After hours, when all but the most curious students had left, Rolf and I ran another collapsing…
Salt fingering
My absolute favorite experiment ever: salt fingering. I know I’ve said it before about another experiment, even today, but this is my absolute favorite experiment and I still get endlessly…
Hetonic explosion
Trying to tweak conditions to force a set number of vortices. We’ve done the hetonic explosion again. This time the group was super careful to calculate the Rossby radius correctly,…
Mixing in a non-stratified and in a stratified tank
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…
Tilting of a frontal surface under rotation
Eddy in a rotating tank. This is an experiment that Pierre and I ran two years ago in Bergen but that – as I just realized – has not been…
Hydraulic jump II
More movies of my kitchen sink. I am really fascinated by the hydraulic jumps in my kitchen sink. I can’t believe I haven’t used this before when I was teaching!…
Hydraulic jumps
Water changing its velocity from above to below the critical velocity. Recently in beautiful Wetzlar: The river Lahn flows through the city below the medieval cathedral at sunset. And I’m…
Hydrostatic pressure
What are students not understanding about hydrostatic pressure? Tomorrow (today by the time this post will go online, I guess) I will present the paper “Identifying and addressing student difficulties…
Student cruises (part 4 of many – weird profiles)
When a CTD profile suddenly looks really weird. As mentioned before, student cruises seem to bring out the weird experiences with CTDs. My theory is that it’s the world testing…
Student cruise (part 3 of many, or – when the CTD didn’t start up)
When a CTD just doesn’t start pumping. In this post, I talked about how student cruises always happen to be on the perfect days, and then in this post I talked…
Student cruise (part 2 of many, or – reading CTD profiles)
Reading CTD profiles. In this post, I talked about student cruises and why they are important for motivation. Here I want to go into a bit more detail on one…
Student cruising
Why student cruises always end up being on the most beautiful days of the year, or: why student cruises are an important part of the education. Remember the picture I…
Rogue waves in a bath tub
Trying to create rogue waves in the bath tub of the infamous “red house”. As a part of their projects, students in the CMM31 in Isafjördur course had to conduct…
Water not in solid body rotation yet
Confusing students even more by discussing how momentum is being transferred from the tank to the water. As you remember, we are preparing for the Ekman experiment and need to…
Water in solid body rotation.
Spinning up a tank until all water particles move with the same angular velocity. Before running the Ekman spiral experiment, the tank needs to be spun up to solid body…
Ekman spiral in a tank.
Tank experiment showing (the effects of) the Ekman spiral. One experiments that has been run in GEOF130 forever is the “Ekman spiral” experiment. A tank filled with water is spun…
Ship-generated internal waves
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…
Langmuir circulation, take 2
Attempt at mechanistic understanding of Langmuir circulation. After complaining about how I didn’t have mechanistic understanding of Langmuir circulation recently, and how I was too lazy to do a real literature…
Velocity of shallow water waves.
The experiment we run to discuss the velocity of shallow water waves. In this post, I discussed how it took us several years to modify an experiment to make it…
Seesawing of standing waves.
Improving one of the experiments run in the GEOF130 lab. One experiment that has been run in GEOF130 forever is the “standing wave”, where a wave is excited in a…
Fjord circulation
Tank experiment on a typical circulation in a fjord. Traditionally, a fjord circulation experiment has been done in GEOF130’s student practicals. Pierre and I recently met up to test-run the…
Langmuir circulation
We think we observed Langmuir circulation, but we don’t understand the mechanism causing it. Recently, my friend Leela came to visit Bergen and we went on a fjord cruise to…
Types of breaking waves depending on steepness of slope – small scale
Video of different types of breakers – small scale. In this recent post we talked about types of breakers depending on the steepness of the slope. But even on a…
Waves breaking depending on steepness of the slope
Waves breaking on slopes of different steepnesses. Depending on a slope’s steepness, waves can break in very different ways. On nearly horizontal beaches, spilling breakers develop. On steeper beaches, plunging…
Mid-Atlantic Ridge
The Mid-Atlantic Ridge above sea level in Iceland. On my recent trip to Iceland, I had to seize the opportunity to take pictures of plate tectonics at work. Imagining oceanic…
Geysers
Photos and movies from geysers on Iceland. I already talked about hydrothermal activity in this post. But then after writing it, we went and did the golden circle tour and…
Hydrothermal springs
Hydrothermal springs that you can visit without a deep-sea submersible. When teaching about hydrothermal springs, I usually use a video a friend of mine took of hydrothermal vents on the…
Interference of waves.
Movie on wave interference – two wave fields arriving perpendicular to each other, interacting and leaving. When talking about waves, it is often difficult to explain that wave heights of…
How a CTD works
Movie on how the most important instrument in oceanography works. On our cruise on the WHOI research vessel Knorr in 2011, Sindre Skrede (find him on twitter or vimeo for many more…
Internal waves in the atmosphere
A photo of internal waves in the atmosphere. Internal waves exist on the interface between fluids of different densities. In the ocean they are mostly observed through their surface imprint.…
Filling the tank
A movie of patterns observed in the flow when filling the tank for this experiment. Even though there are tons of scientific things to discuss with this movie, like the…
Details of lee waves in the tank.
A movie focusing on details of the lee waves in the tank. In this post, we investigated lee waves in a tank in a general way. Here, I want to…
Surface imprints of internal waves
How internal waves in the ocean can be spotted on the surface. Under certain conditions, internal waves in the ocean can be spotted at the ocean’s surface due to changes…
Internal (lee) waves in a tank.
Lee wave experiment in a large tank with a moving mountain. In this previous post, we talked about internal waves in a very simple experiment. But Geophysical Institute has a great…
Heat capacity of air and water
Hands-on activity to better understand the concept and consequences of heat capacity. Also a great party trick. Imagine you take a balloon. Any kind of normal balloon. You blow it…