Thermal forcing in a non-rotating vs rotating case: Totally different results

On Thursday, I wrote about the thermally driven overturning circulation experiment that Torge and I did as past of our “dry theory 2 juicy reality” experiments, and mentioned that it was a non-rotating experiment in a class about rotating fluid dynamics.

I showed you the rectangular tank, but we also used a cylindrical tank with cooling in the middle that is a rotational symmetric version of the “slice” in the rectangular tank. In both cases we see the same: Cold water sinks and spreads at the bottom and is then replaced by warmer water.

But when we start turning the cylindrical tank with the cooling in the middle, cool things start to happen. I’ve blogged about that experiment before, but here is a pic of the circulation that develops. Instead of an overturning, we now get heat transport via eddies!

This is actually a really nice way to show again how hugely important the influence of rotation is on the behaviour of the ocean and atmosphere!

Salt fingers in my overturning experiment

You might have noticed them in yesterday’s thermally driven overturning video: salt fingers!

In the image below you see them developing in the far left: Little red dye plumes moving down into the clear water. But wait, where is the salt? In this case, the “double” in double diffusion comes from heat and dye which are diffusing at different rates. As temperature’s molecular diffusion is about 100x faster than that of salt (or other things that have to physically change their distribution, rather than just bump into each other to transfer energy), the red and clear water quickly have the same temperature, but then the red dye makes the red water more dense, hence it sinks.

Over time, those fingers become more and more clearly visible…

Until after a couple of minutes, we see that they are really contributing to mixing between the two layers.

Even though double diffusive mixing happens in the ocean, too, the scaling of these fingers is of course totally off if we think of this tank as for example the northern half of the Atlantic. But then so is the density stratification… But it’s always good to keep in mind that while this experiment is showing some things quite nicely, there are also things that are artefacts of the way the experiment is set up and that aren’t analogous to how things work in the ocean.

A really nice and very new-to-me way of observing them is from above:

This is a picture that was taken fairly early in the experiment, when the layers hadn’t propagated far yet and the salt fingers weren’t being pulled back by the shear between the layers. But it’s nice to see how the dye is concentrated in those downward moving fingers, isn’t it?

Thermally driven overturning circulation

Today was the second day of tank experiments in Torge’s and my “dry theory 2 juicy reality” teaching innovation project. While that project is mainly about bringing rotating tanks into the theoretical teaching of ocean and atmosphere dynamics, today we started with the non-rotating case of a thermally driven overturning circulation.

Very easy setup: A rectangular glass vase filled with luke-warm water. A frozen cool pack for sports injuries draped over one end (which we’ll think of as the northern end) provides the cooling that we need for deep water formation. The deep water is conveniently dyed blue with food dye. Red food dye is warmed up and added to the “southern end” of the tank, and voilà! An overturning circulation is set up.

Watch the sped-up movie to see what happens:

As you will notice, this circulation won’t last for a very long time. Since we are adding neither warming nor mixing, the cold water will eventually fill up the tank. But it’s still quite a nice experiment!

(And should you have noticed the “salt fingers” forming towards the end of the movie, I’ll write about those tomorrow)

And here is the nice group of students that humoured me and posed for this picture. It’s fun with such a motivated group that comes up with new things to try all the time! :-)

Burning soap bubbles

The other day I was thinking about fun experiments to do on a Birthday party for kids (won’t spoiler here whose kid that might be, and also, coincidentally, it was on Jenny’s Birthday! Happy Birthday, Jenny! :-)) and I realized I never posted the “burning soap bubbles”. Probably because I still can’t think of a good reason why it belongs on a blog on “adventures in teaching and oceanography”, but since I dug out the movies that my friend Dési made and narrated more than 2 years ago, and it’s fun to watch, (and also it’s much faster for me to google my blog for this experiment than to search for it on my phone if I ever need it again): here we go!

English short version of Dési’s narration: Take dish soap and mix it in water. Bubble lighter gas into the water to create bubbles. Take them up in your hand, bring a lighter close, and that’s it! It doesn’t get hot or anything, but it looks very impressive!

Destroying the diffusive layers in a latte in order to observe the insulating properties of milk foam

Have you ever noticed how, if you stir your latte*, when you pull out the spoon it’s piping hot, yet there is no steam rising from the latte itself? That’s because the milk foam on top is such a good thermal insulator thanks to all the tiny air bubbles trapped in it. Cool, isn’t it?

*I never noticed before today, when my friend Sara pointed it out, because I have NEVER before put a spoon in my latte. Because I am always observing double-diffusive mixing in my latte and would never do anything that might destroy the stratification. But this once it might have been worth it. The things we do for science… :-D

Do you love #kitchenoceanography, too?

November’s #SciCommChall: Science communication on coasters!

Remember #SciCommChall? I started it almost 2 years ago and have recently felt a little burnt out when it came to coming up with new challenges and motivating people to join. But luckily Nena, #SciCommChall enthusiast from Day 1, stepped up. Nena has posed #SciCommChall-Challenges before, and her current challenge is a lot of fun: Bringing science on coasters to make it visible in pubs!

And I am happy to report that no matter how burnt out about #SciCommChall I felt only this morning, I still had to respond to the challenge and come up with a couple of quick ideas right away. And now that I did these, there are so many other possibilities in my head! Thanks for the inspiration, Nena! :-)

October #wavewatching: reposting my Instagram posts

My scicomm Instagram @fascinocean_kiel is back! As in it’s something that I am putting more thought into again. While it started off strong almost two years ago with daily posts written specifically for Instagram, I’ve been in a bit of a slump. For a while, I just posted pictures from current blog posts with a description like “read more about this on my blog”, but this didn’t feel satisfying. It also meant that I had a lot of #wavewatching posts on my blog, which I felt were taking over what I want the focus of this blog to be on. So the current compromise is that all the #wavewatching stuff happens over on Instagram (in German, but they have a really good translator at least to English), and only the most outstanding highlights will get their own post on here. But there will be a summary post of what went on on Instagram every month or so. Or at least that’s the plan for now!

I started out posting on Instagram again at the end of my month-long trip to Bergen, Oslo, and finally Gothenburg, when I got the exciting opportunity to “meet” Anna Wåhlin’s AUV, Ran, and take part in a short cruise on RV Skargerak to see her in action.

Btw, the reason I am posting more selfies now is that I’ve been thinking about the research around #ScientistsWhoSelfie that shows that showing selfies is beneficial for being perceived as warmer, more trustworthy and also as reducing gender-related stereotypes about who can be a scientist (at least if you are a woman posting selfies). And I think that it’s a very easy contribution to make if it helps achieve scientists in general being perceived as more trustworthy and also helping people to see that scientists are not always old, white men with beards and messy hair in lab coats. Sometimes it’s also me, sitting in the rain, grinning because I get to see a cool AUV up close! :-)

On that cruise, there was of course also CTD work going on.

And work doesn’t stop just because it gets dark…

Then this is the library in Gothenburg — a beautiful building that I passed several times on the way to the institute, and always admired.

And then I was on the ferry to go back home! In a cabin with sea view! That made me so happy. I was so tired after that exciting month, so sitting in my bed instead of standing on the cold, wet and windy deck felt like heaven :-)

And then we were home! Or at least almost. The Kiel lighthouse is situated offshore in Kiel bight, and it’s where the pilot station is (you see the pilot ship returning to the lighthouse in the picture below)

And this is the ferry arriving in Kiel port. I always love watching how these big ships are carefully maneuvered into port!

And this is another lighthouse on our way into Kiel port, and the ferry’s wake.

And then we had a little throwback, reminiscing of Pierre & my adventures on Straume Bru.

And then we are back to wave watching in Kiel! Reflections on the sea wall, and total reflection.

And what was going on here with all that foam? And is foam actually a passive tracer, or is the distribution also influenced by surface tension or other stuff?

Here is where the foam ends up in Kiel fjord. And what I find fascinating is how towards the upper edge of the picture, the ring waves of the water draining into Kiel fjord are really visible, whereas in the lower edge the picture seems dominated by wind waves. Even though both types of waves are probably fairly equally present in all parts of the picture, just the different angle makes one or the other appear more prominently.

It’s really fun to bring this collection of screenshots of my Instagram together. I’m a little impressed by how many wave pictures I post!

Here we are looking at a ship’s wake that is reaching the beach.

And I just love the sound of waves on a stony beach!

Not every day is wave watching day, sometimes we just have to be content with water.

And autumn leaves…

But then there is of course always the opportunity to make the waves you want to see (and be the change you want to see ;-)). Here we are looking at hydraulic jumps in the sink at work.

Although with these views it seems almost silly to go to a sink for wave watching opportunities…

But now a wave riddle. What’s happening between this pic…

…and this one? Any ideas, anyone?

And then there was the day where I went to play with four rotating tanks simultaneously in the morning, and then later to a conference on “Screening the Sea”, audiovisual media and the sea. That was one exhausting day!

The next day, walking down to Kiel fjord, I was in a bit of a gloomy mood and thought that there might not possibly anything going on that I hadn’t taken a million pictures of already. And luckily I was so wrong! My faith in daily wave watching was completely restored when I saw the sediment clouds and how they behaved in comparison to surface waves.

And then there was the day with very low water, where we could really nicely see how the shape of the ground influences the waves.

Shallow water waves always look a bit ridiculous, don’t they? Like sausages moving onto the beach.

And then I finally combined a lot of selfie movie clips about meeting Ran, the Autonomous Underwater Vehicle, into a 5-min-movie and advertised that on my Insta, too.

When I went to go vote, I happened to wave watch in a spot that I don’t usually go to. Also fun! And nice to see how this floating bridge is sheltering parts of the lake from the wind. Although some waves come through, as you see in the deformation of the reflections of the hand rails.

And then I went to Hanover to give a workshop at their university. But first, I had to go do a picknick with Frauke :-) And, of course, a wave riddle. Can you guess who or what made the waves in the picture below?

Frauke is the best. She brought soap bubbles to our picknick! And there is so much physics in soap bubbles. From the films that change color as the bubble ages, to the shapes they form, to how their size is related to how hard you blow when making them. So cool!

Also super interesting to watch how the soap is sliding down the soap bubble, leading to a discoloration starting at the top, sliding down, until it finally bursts when enough water has evaporated.

And now for some drop photography! Water is dripping down from somewhere fairly high up, so the crown of droplets that is thrown up into the air by the surface bouncing back after each drop is quite large! As I was watching, someone moved a window in the office building right there, so that the sun’s reflection lit up the point of impact perfectly.

Then a morning walk with my sister in Hamburg. There was some fog in the shadow-y bits of the river but it’s really hard to spot…

And then back home in Kiel! Perfect wave watching, right?

Later that same day my favourite spot at the Holtenau locks.

I just always love it there!

And then: A day full of jellyfish watching! They are SO beautiful! (For more jellyfish pics, see this blog post)

Jellyfish!

And one last selfie with jellyfish.

So this is where we are at with my Instagram @fascinocean_kiel now: 444 posts! And the last three all featuring jellyfish :-D

And I am thinking about switching it back to English again. So much for knowing my goals with this profile… :-D

#WaveWatching, beautiful jellyfish, miniature rip currents, double-diffusive mixing in a Latte

So today I spent a perfect day at the beach in Schilksee, at the mouth of Kiel Bight.

Not a lot of wind (you see the gusts of wind further offshore) but perfect wave watching nevertheless. Look at this beautiful wake!

Here I wanted to take another picture of a wake, but the seagull had already taken off by the time I had my phone ready. Still beautiful though!

And in this picture I just love the geometry.

I have never seen as many jellyfish as today. They were everywhere! So I had to take a selfie.

They look so beautiful, and give such a nice depth to the picture below!

We were watching for quite some time.

And more selfies. But isn’t the jellyfish just amazing?

In the gif on top this post you see it swim, here you have to admire each picture individually :-)

I think they are sooo beautiful!

Coffee break: Double-diffusive layering in a Latte! Super clear layers, so I totally invaded someone else’s personal space AND took pictures of their drink. The things we do for scicomm ;-)

On the way back. It was only around 2:40 when the picture was taken (as you can confirm if you recognize the ferry in the picture), but the light already looks like it’s the evening. And another beautiful wake!

And then, more exciting stuff: Miniature rip currents!

When the water is pulling back, they really become quite strong and impressive and it’s easy to imagine that they get super dangerous really quickly when they are a little larger.

Now with the small waves, they just look beautiful.

And did I ever mention that I looooove waves just before they break?

Have a great evening, everybody!

Guest posts, take-overs, interviews, and why I love them

Guest posts, take-overs and interviews are a great alternative to maintaining social media channels for every scientist / project / institution individually, if that isn’t what you want to be doing (or — as in my case — a great addition)

As I am preparing a workshop on online science communication, I have been thinking about how maintaining a quality social media presence requires high levels of dedication and commitment, as it requires a lot of work and time. And sometimes, for whatever reasons, committing that sort of time to online scicomm just can’t be the priority, and that is ok. So what do I want to recommend to people who are interested in principle, but who have concerns that it will be too expensive to maintain in the long run in terms of time or energy or ideas or motivation, or whatever else the limiting factor might be?

I think there are ways to do cool and impact-ful online scicomm without building and maintaining a personal social media presence (or focussing on one specific channel and audience and not feeling bad about not doing all the things that one could possibly do).

But first, I believe it is super important to get clear on why we want to appear on social media in the first place.

What are your objectives?

Being clear about what you are trying to achieve is always really good advice, for science communication on social media, outside of social media, for life in general. But especially if we are trying to minimize effort and maximise effects of online scicomm, it helps to be really clear about what the goal is.

If you want to build a community or regularly update a group of people on your project’s progress, having your own social media channels might be the way to go. And I am in no way trying to dissuade you from having your own social media channels! All my suggestions below also apply if you do this in addition to maintaining a regular presence on social media.

If you wanted to, for example,

  • convey a message without necessarily becoming visible as a person
  • create short-term visibility for a specific project / result / event
  • be highlighted to a specific audience that isn’t one you regularly (want to) engage with
  • brush up your CV on the online scicomm side (without too much regular work)
  • prepare content occasionally, but not regularly
  • dip your toes into doing scicomm in a specific format to see how it works for you,

below are some options worth considering.

Who is your audience?

Depending on your goals, you might want to address audiences as specific as, for example,

  • students at a specific university
  • young adults living in a specific country (or reading in a specific language)
  • PhD students working on polar sciences.

And you might want to reach all of them at different points in time, for different reasons and with different messages. For each audience you might want to reach, there are likely accounts already targeting that exact same group of people. The clearer you are about who your audience is, the easier it is to find accounts that have build already that audience to collaborate with.

What is your message?

And does conveying your message include interaction with your audience?

Once you are clear on all this, here are a couple of options worth considering.

Take-overs of rotating accounts

For many communities, rotating accounts on Twitter and Instagram exist. Those are accounts that are focussed on specific topics but are run by different people each week. The benefit of taking over those accounts is that there is a large established audience interested in your kind of content already, that you are instantly exposed to once you take over the account.

Take-overs typically require you to commit to posting on the channel a couple of times throughout the course of a week, and, depending on the size of the channel, it can be quite scary especially if you don’t have a lot of experience using social media beforehand. And, since those channels typically have quite a large following, you should not underestimate the time it will take to prepare content, overthink it, post it, agonize over it and regularly check how it is being received, and respond to people’s comments. But my experience with doing this has been very positive indeed.

For example, last year I took over @GeoSciTweeps (an account with, at that time, 4.6k followers, where each week a different person working in gesosciences presents what they do) and @IAmScicomm (where people working in/on/with science communication present themselves) with then 18.6k followers. Both weeks were great experiences that led to me making super interesting new connections and friendships. Depending on which community you want to interact with during your take-over week, there are many many more rotating accounts and it is definitely worth taking a moment to figure out which is the right account for your purposes.

My plan for my takeover of @IAmScicomm in October 2018

Similar accounts also exist on Instagram, for example @nordicpolarscience, which we used earlier this year to inform an audience of mainly students in anything related to nordic polar sciences about our fjord oceanography student cruise. See example below:

One of our guest posts on @nordicpolarscience on Instagram

Guest “take overs” for institutions

Instead of doing a take over on a rotating account, you could also do one for an institution like your university. I was asked to take over Kiel university’s Instagram @kieluni for a couple of days, and it was fun!

Caution — “take over” for an institution might mean something different than for rotating accounts. In case of Kiel uni it means you have to pre-produce content, and they will post it themselves. Which is actually very convenient (if you realize this early enough, which I did not. But you live and learn ;-)).

Instagram profile of Kiel University. The three posts visible at the bottom are mine!

This take over had unexpected effects: Before our first session using 4 rotating tables simultaneously, one of the students approached and asked me if it was me who did this takeover with the cool tank experiments on @kieluni weeks ago! Glad to prove to Torge, who was part of that conversation, that Social. Media. Works! :-)

Guest posts

Sometimes there are blogs that cater to your intended audience that are happy to accept guest posts.

A while back, I wrote a guest post at Sci/Why, a blog for Canadian science writers for kids. They invited me to write the guest post, and why not? It was fun!

Screenshot of the Sci/Why website

A really good example for a very successful guest posts is one I recently hosted on my blog: Dan’s post on an analogue activity to understand how machine learning works. This post received a lot of attention on Twitter and I am excited to provide my platform to give visibility to such a great project! If you are interested in writing about anything related to “Adventures in Oceanography and Teaching”, please get in touch and I am happy to host a guest post!

Another example of a guest post I did is on my friend Alice’s blog and Instagram for her #experimentalfridays series.

Guest post on Alice’s Instagram @scied_alice

What makes guest posts really convenient is that you can write them whenever it suits you, edit them as often as you might like, talk to your host about how to make them the best fit for their audience, etc.. So in a way it might feel like it is the “safest” way to do online scicomm, because it’s the slowest, most familiar way.

Being featured on accounts

There are also a lot of accounts that are happy to feature you and/or your work because their goal is community building.

For example, I was recently featured on @WeAreCAU on Instagram. Their goal is to feature people with a connection to Christian Albrechts University Kiel (CAU — hence “We are CAU”), and as an alumna I thought this was a great opportunity to connect with people at this university.

Me being featured on @WeAreCAU on Instagram

Being featured this way was also a super easy thing to do, all that was needed was a picture of myself and a short text, which I wrote when it suited me, and which they then posted when it worked with their schedule.

Providing information to other accounts

Sometimes, the goal is just to get a message out there without necessarily becoming visible as the person / project / institution behind the message. I recently met the person behind @doktorwissenschaft, a very popular german Instagram account, “Dr. Science”, who posts two science facts every day. He was happy to receive a list of ocean facts (complete with references ;-)). And using his account with 38k followers (and 3k “likes” on my most recent post on his profile) gives my content so much more visibility than I could achieve with my own channels, so I am really happy about this collaboration. Win win!

The popular Instagram-profile “Doktor Wissenschaft” posts twice daily facts in physics, chemistry and biology!

One of the ocean facts I provided to Doktor Wissenschaft

Again, this is a super easy collaboration, as both parties can work on their own schedule.

Giving interviews

This might actually be the most conventional way of reaching new audiences. And in a way it might also be the easiest way, because you are interacting with a host that will help you tailor your message to their audience, that they know a lot better than you do.

I’ve done this several times over the last year, for example on Susanne Geu’s blog, and on Ronja & Maxie’s podcast “Treibholz”.

My experience doing these guest posts, take overs, etc.

Time commitment

Depending on the kind of collaboration you choose, you need to be aware of how much work it will bring with it. I did the two twitter takeovers mentioned above while being a visiting scientist in Bergen, thinking that then at least I would have something to talk about. But trying to work on other things at the same time and going on student cruises, and that was actually a little overwhelming. Maybe also because it was the first time I tried doing something like this, but I would definitely recommend doing such takeovers on a slow week at home rather than a week where you want to make the most of visiting a place, chatting with people you don’t get to see regularly, go on cruises, etc.. Also do it during a week / in a place where you know you will have good internet access. So being on a ship might not be ideal.

On the other hand, if you choose to work with pre-produced content on channels that you will not be administering yourself when your content is being posted, this is something that you can prepare over as much time as you like and thus fit it around your schedule. So this might actually be something worth considering for a really busy and important week, on a field trip, a conference, whatever, the week your big event is taking place, to raise awareness for whatever you are up to that week without actually having to do anything about it during those busy times, and without depending on having good internet access. Provided everything is prepared beforehand…

Would I do it again?

Yes!!! As I was writing this post, more and more examples of where I have contributed to other people’s online scicomm came to my mind. I didn’t realize I had been doing it so much. And it was fun, I enjoy looking back at each individual interaction and all the different products that came out. It was also work. Of course, being suddenly able to reach audiences that I wasn’t familiar with and some that were so much larger than my usual audience was also both exciting and terrifying. I would totally do it again and I would totally recommend trying it!

And also if you are thinking about taking up a new-to-you form of scicomm, doing a guest appearance somewhere is a great way to test the waters. The coolest scicomm idea doesn’t actually carry very far if it turns out that you HATE the app you need to work with in order to communicate on a specific social media channel, you really can’t find a lot to say on a specific topic, or you find it annoying to write for a specific kind of audience. So this is a really great way to see what it would be like to do this kind of scicomm and get some reactions!

Meeting Ran, the Autonomous Underwater Vehicle

Two weeks ago in Gothenburg, I was lucky enough to meet Ran, Anna Wåhlin’s Autonomous Underwater Vehicle.

I posted a lot about that on Twitter, but have been wanting to combine the pics and short clips into a movie. But I just couldn’t be bothered to do something about the sound, so I put it off, but eventually I figured that I really wanted my mom to watch it so here we go. Please excuse the bad sound quality. I am currently looking into small microphones to work with my phone… Any advice?

(See pictures below the movie if you are interested)

And here we go! Selfie with Ran!

Anna and Johan doing pre-dive checks and mission planning

Another selfie with Ran. Can you tell that I am excited to meet her?

But wow, it takes a while until she’s ready to go into the water! ;-)

But there she is, finally ready to dive. Can you spot her?

When Ran is diving, there isn’t really a lot to do. Except, of course, wave watching! I always love looking at how the waves are claiming back the area that a ship just vacated (which you see from the turbulent wake).

And there she is again, ready to be recovered!

Science is such a team effort. We wouldn’t be able to do any oceanography without the amazing captains & crews on the research ships. And it’s no different on RV Skagerak. They are just lovely!

And Ran is on the hook to be pulled back on board!

This is a lot more difficult that I imagined!

Oh, and then there were a couple of CTD stations to get some data to calibrate the sensors on Ran with. I love CTDs :-)

Next recovery…

And more wave watching!

On RV Skagerak, communications are very direct. Just open the porthole and you are ready to drive the CTD! :-)

No rest for the wicked… Recovering Ran at night.

Exciting times!

Thanks again for having me, Anna! I really enjoyed it so much! :-)