Tag Archives: #sciart

An art & science collaboration with Wlodek Brühl: #dropphotography

If you are here because you saw my title or talk at the Science in Public conference in Manchester and are curious about #dropphotography as a form of art&science collaboration in scicomm — a special welcome to you! If you are here for any other reason — welcome anyway! :-)

One of my favourite pet projects right now is the #scicomm collaboration with the artist Wlodek Brühl.

The idea behing the collaboration is very simple: Wlodek does awesome drop photography like what he showed in his recent exhibition, or the picture below: Drops falling into water, creating sculptures that he captures with digital photography.

I, on the other hand, use the opportunity of having people fascinated and mesmerised by this art, and curious to learn more about it, to talk about — what else? — physics! :-)

For one example of what that collaboration looks like in practice, check out my speech at the opening of his latest exhibition. We have a workshop coming up this autumn that we will run together, as well as other exciting projects which are, unfortunately, still secret. It’s going to be awesome, though!

But back to physics: Creating the exact sculpture you want requires enormous precision. This is what the setup looks like: Reservoirs above a vessel in which the drops fall. And a complex setup of flashlights and a digital camera, all coordinated by a custom-made piece of software.

The most important thing influencing the momentum with which a drop hits the water below is the height it falls from. Below, pictures are taking at constant intervals after drop release, yet you see that the for each new picture, the drop fell a little further than it did in the previous interval — it fell a little faster due to acceleration of gravity. Thus the longer you let a drop fall (i.e. the higher the drop falls from), the more it will accelerate, bringing more energy into producing a fountain.

The next thing that needs to be very precisely controlled are the opening times of the valves that release the drops. Not only when they open, but also for how long. Consider opening times of the valves in the picture below, left to right: 50, 55, 60, 70  milliseconds (The series of pictures on the left you know already from the “acceleration of gravity” pic above).

Depending on how long the valve is opened, different volumes of water are released, forming different drops. Easy to imagine that this will lead to different fountains once the drops hit the water below!

So what happens exactly once the drop hits water? The water surface gets deformed as the drop pulls it downwards. Due to surface tension, it then bounces back up, bringing up a column of water, that then collapses back down. And all these disturbances radiate ripples away from the original point of impact — capillary waves! (Capillary waves are super interesting because they behave very differently from “normal” gravity waves, but that’s a topic for a different post!)

But so that’s how fascinating it is to watch just one drop falling into water. Now imagine several drops falling one after the other, such that a second or third drop hits the column rising up after the first drop already hit the surface? That’s what makes these interesting umbrella shapes:

As you can imagine, there are tons of parameters you could vary now. Not only fall height and drop size, time lag between drops, number of drops that fall, but also viscosity of the fluid, shape of the bowl the drops fall into, all kinds of things. And that’s only using the easiest setup! You could also imagine using several valves, or air pressure to shoot drops with more momentum, or even have water shooting up from below (all of which Wlodek has done!).

And then, of course, depending on when exactly you choose to take a picture of the sculpture, you will see it in very different stages of formation and decay. You see the attempt of surface tension to minimise disturbances, instabilities that still form along the rim of the umbrellas which ultimately burst into many different small droplets…

Do you see the potential to talk about physics pretty much forever here? I love it! :-)

Opening speech for Wlodek Brühl’s art

You might remember that I had the honour of giving a speech at the opening of Wlodek Brühl’s art exhibition back in spring. Preparing my presentation for the Science in Public conference in Manchester next week (that I am immensely looking forward to!), I noticed I never posted the speech. Below is what I sent Wlodek in advance to prepare him for what I might say:

Lieber Wlodek, sehr geehrte Damen und Herren,

es ist mir eine große Ehre, die einleitenden Worte auf dieser Vernissage, dieser Eröffnung der Ausstellung von Werken Wlodek Brühls, zu sprechen und Sie hier Willkommen zu heißen.

Obwohl genau das die Wortbedeutung von „Laudatio“ist, ist mir ausdrücklich untersagt worden, den Künstler zu loben – vom Künstler selbst. Also werde ich heute lieber über Physik sprechen. Wenn Sie die Bilder von Herrn Brühl betrachten, denken Sie dann nicht auch sofort und unausweichlich über Physik nach?

Springbrunnen kennen wir zu Genüge, in Pfützen fallende Tropfen auch. Und letztendlich sehen wir hier genau das, wenn auch mit etwas mehr technischem Aufwand umgesetzt, um die entstehende Skulptur ganz genau beeinflussen zu können. Deshalb kommen uns die in diesen Fotografien gezeigten Formen seltsam vertraut vor – richtig gesehen haben wir sie aber noch nie. Auch wenn genau solche Strukturen um uns herum existieren (und dabei ist anzumerken, dass jede dieser Skulpturen einzigartig ist, wie auch keine Schneeflocke exakt einer anderen gleicht), mit bloßem Auge können wir sie nicht erkennen, weil sie nur für Bruchteile von Sekunden bestehen und unser Gehirn schlicht zu langsam dafür ist. Solche Skulpturen trotzdem bildlich festzuhalten gelingt mit vielen technischen Tricks: Mit computergesteuerten Ventilen, die Tropfen so auslösen, dass sie genau mit anderen Ventilen, dem Blitzlicht zur Beleuchtung und dem Auslöser der Kamera abgestimmt sind. Sichtbar werden dann Skulpturen und nicht nur verwischtes Wasser, weil die Skulpturen in einem stockdunklen Raum für ein Bruchteil einer Sekunde von einem Blitz beleuchtet werden, so dass trotz der längeren Belichtungszeiten der Kamera auf dem Bild nur dieser eine, enorm kurze Moment sichtbar wird, in dem es – exakt zum richtigen Augenblick – geblitzt hat.

Aber kommen wir zur Physik. Wenn Sie diese Ausstellung bei – aus physikalischer Sicht – einfacheren Bildern anfangen und sich dann langsam steigern möchten, würde ich empfehlen, in diesem Raum zu beginnen.

My picture of art by Wlodek Brühl, taken and published with kind permission.

Hier drängt sich mir zum Beispiel die Frage auf, warum die Skulpturen von unten aus dem Wasser nach oben zu wachsen scheinen, bevor sie sich ausbreiten, verzweigen? Der Schlüssel hier ist die Oberflächenspannung des Wassers. Die Wasseroberfläche, durch einen fallenden Tropfen nach unten ausgelenkt, schleudert den Tropfen wie ein Trampolin wieder nach oben und wölbt sich selbst hinterher, bäumt sich auf, bevor sie wieder in sich zusammen fällt. In einigen der Bildern kann man diesen nach oben geschleuderten Tropfen sogar noch erkennen.

My picture of art by Wlodek Brühl, taken and published with kind permission.

Und dann sehen wir im oberen Teil vieler der Skulpturen Formen, die wie Schirme oder Leselampen aussehen, oder wie Vasen. Warum sind diese Strukturen manchmal nach oben geöffnet, manchmal nach unten, manchmal voller filigraner kleiner Ärmchen am Rand? Das sind eigentlich schon zwei Fragen in einer. Die Form der Kelche hängt davon ab, wie schnell sich zwei Tropfen aufeinander zu bewegen und ob ein großer auf einen kleinen trifft oder umgekehrt. Die kleinen Ärmchen sind Instabilitäten, die entstehen, kurz bevor der Schirm zerfällt. Schirme ohne Ärmchen sind also genau in dem Moment belichtet und eingefangen worden, als noch alles stabil war. Bruchteile von Sekunden später wären auch sie instabil geworden.

My picture of art by Wlodek Brühl, taken and published with kind permission.

Und wenn Sie mit diesem Blick durch diese Ausstellung gehen, werden Ihnen noch viele andere Fragen kommen. Manchmal, zum Beispiel, sehen wir Skulpturen, die auf zwei Säulen zu ruhen scheinen. Wie sind diese wohl entstanden? Und dann sind die Skulpturen farbig – und die Farben sind direkt in der Aufnahme entstanden und nicht nachträglich digital eingefärbt. Das wurde in diesem Raum durch farbige Blitze gemacht, in den anderen beiden Räumen durch eingefärbtes Wasser.

My picture of art by Wlodek Brühl, taken and published with kind permission.

Wenn Sie als nächstes dann in den Raum dort hinten weitergehen, sehen Sie Skulpturen, die an der Wasseroberfläche gespiegelt sind. Durch die Spiegelung hat man auf ein mal zwei unterschiedliche Perspektiven auf die Skulptur und kann jetzt Strukturen noch genauer beobachten, um über sie nachzudenken.

My picture of art by Wlodek Brühl, taken and published with kind permission.

Im dritten Raum sehen Sie die neuesten Kunstwerke von Herrn Brühl, die vor wenigen Wochen erst entstanden sind. Hier wird die Physik noch komplexer. Zusätzlich zu all dem, was ich gerade schon über fallende Tropfen erzählt habe, kommen hier noch mit Druckluft angetriebene Fontänen hinzu. Und zwar einfache, die in der Mitte der Skulptur gerade nach oben schießen, und dann auch solche, die aus einer sich drehenden Turbine nach oben und außen geschleudert werden, erst einen Kelch bilden und dann in einzelne Tentakel zerfallen. Und in diesen Bildern sieht man manchmal auch die Schlieren und Pigmente der verwendeten Farben!

Wenn man wollte, könnte man an jedem einzelnen Kunstwerk stundenlang beobachten, grübeln und diskutieren. Wie sähe eine Skulptur wohl aus, wenn ein Tropfen größer gewesen wäre als er war, oder etwas später gefallen, oder vielleicht aus einer anderen Höhe? Oder wenn das Bild Sekundenbruchteile eher oder später gemacht worden wäre und uns damit einen anderen Zeitpunkt der Entwicklung und des Zerfalls der Skulptur gezeigt hätte? Was, wenn anstelle von Wasser zum Beispiel mit Honig gearbeitet würde? An Ihren Gesichtern sehe ich, dass diese Fragen Sie schon jetzt faszinieren. Das ist genau die Physik, die ich speziell bei den Tropfenskulpturen von Herrn Brühl so fesselnd und aufregende finde!

Ich wünsche Ihnen viel Spaß in dieser Ausstellung – dass Sie die beeindruckende Kunst von Herrn Brühl als Kunst genießen können, aber dass Sie sich vielleicht an manchen Stellen auch fragen, wie genau er es wohl geschafft hat, solch ein Meisterwerk entstehen zu lassen. Ich bin mir sicher, dass Herr Brühl Ihnen gerne Rede und Antwort stehen wird! In diesem Sinne: Herzlich Willkommen!

Vernissage of “liquid art”: The perfect opportunity to combine art & physics to do some scicomm!

If you don’t want to “preach to the choir”, how do you, as science communicator, reach new audiences occasionally?

One way that I tried today is to give the (invited, I swear!) laudation at the vernissage of Wlodek Brühl‘s exhibition on “liquid art“. The idea was that visitors would mainly come to the event because they are interested in art itself, but that I will try to give them a new perspective on the art by exposing them to the science behind it. Which I think is a pretty cool concept!

Yesterday, I got a sneak peek into the exhibition which features new art that isn’t even two weeks old! I took pictures of some of the art to show on this blog (with Wlodek’s permission!).

Let’s start with a sculpture that isn’t even part of the actual exhibition but that is displayed in my living room (and I love it!!!): A very simple drop sculpture. A drop fell onto a water surface. Due to surface tension, the water surface deformed, got pulled down, bounced back, overshot, and a drop shot up again, pulling a thin trail behind it. As the drop was flying upwards, it got hit by a second drop which fell straight on it. That second drop splattered into this umbrella, which is starting to disintegrate into small instabilities that form tiny filaments. A fraction of a second later and the whole thing would have collapsed and look totally different.

My picture of art by Wlodek Brühl, taken and published with kind permission.

That’s part of the art of capturing these sculptures: timing. Not only does one need to be super precise in the timing of drop releases, one also needs to capture the exact right moment to light the dark room with a flash, which is a lot shorter than the exposure time of the camera. Of course it’s all controlled by a computer!

But here is an impression of the exhibition itself.

My picture of art by Wlodek Brühl, taken and published with kind permission.

I’d like to start out with some of the older art from 2016 which is easier to explain: “Simple” drops like you see to the right of the door above, then double pillars to the left of the door, and then reflections, before we move on to the kind of art that you saw at the top of this post.

In the picture below, what happened is pretty similar to what happened in the picture above: A drop fell, bounced back up again and was hit by a second drop. The second drop hit the first one when that one was still fairly fast, therefore the vase-like structure. (And don’t you just love the waves that you see on the water surface? I feel like I see the actual dynamic process of the surface rising up!)

My picture of art by Wlodek Brühl, taken and published with kind permission.

Or below, another similar setup, except here the drops collided in such a way that the larger, bottom one formed an umbrella-like shape, whereas the upper one rose as a vase.

My picture of art by Wlodek Brühl, taken and published with kind permission.

It gets more complicated if two drops are released simultaneously as below, and then a third one hits them in the middle with a little time delay to form the umbrella, and a fourth drop is still falling down and hasn’t reached the sculpture yet.

My picture of art by Wlodek Brühl, taken and published with kind permission.

So much for the “simple” structures, now on to more complicated ones. The ones below are similar in their setup to the ones above, but now they are photographed against a black background and in a large, black dish. Therefore we see the reflection of the sculpture on the water surface. This lets us look at different structures within the sculpture from two angles, making it even cooler to think about all the physics going on here!

My picture of art by Wlodek Brühl, taken and published with kind permission.

But now on to stuff done with more fun toys:

These are the newest works of art that Wlodek did only within the last two weeks! I personally prefer the translucent, fragile, light sculptures like the one in my living room, but I can also really appreciate those bouquets of spring flowers for their dynamic and lively shapes.

My picture of art by Wlodek Brühl, taken and published with kind permission.

Below I am showing a larger version of the sculpture to the very right above. In these new sculptures, Wlodek isn’t “only” working with drops, but now he has started to incorporate colored jets that are driven up by pressurised air. See how the yellow central jet broke through the umbrella formed by the orange drop that dripped on it from above?

Additionally, Wlodek is building vases around the bouquets by pushing dyed water through a rotating turbine. This vase breaks up into tentacles when it gets unstable!

The sculpture below is called “sundae with umbrella” and I cannot un-see this!

My picture of art by Wlodek Brühl, taken and published with kind permission.

But mostly I see flowers, specifically orchids. Below, the yellow drop from the top didn’t hit the green-ish jet from below completely center, therefore the latter broke up and seems to be turning towards us, wrapped in the orangey-yellow vase that has become very unstable on one side, but not so much in the back. Don’t you just love how the rims bulge together due to surface tension?

My picture of art by Wlodek Brühl, taken and published with kind permission.

In any case, I had a blast, even though, judging from the picture below that shows me giving the laudation, it doesn’t seem like it. Do I always look this serious? But the feedback I got was that everybody enjoyed looking at Wlodek’s art through a physics lense, at least after they got over their initial shock that they would have to listen to physics on their artsy Sunday morning. So this is definitely a scicomm format I want to explore more!

Me (in stripes) with the artists Regine Hahn (left) and Wlodek Brühl, as well as the host, chairwoman of Kunstkreis Preetz. Picture by Frauke Voitle, used with permission.

Vernissage of water sculpture photography by Wlodek Brühl, with explanations of the physics behind the pictures by yours truly!

I am a huuuge fan of Wlodek Brühl’s liquid art: Pictures of water sculptures that are created with focus on the tiniest of details, that only persist for milliseconds, but that are captured forever in all their fragile beauty. And I think these pictures are an awesome tool in science communication — I see so much physics in them (some of which I wrote about here already), and even if you come to an exhibition for the art, who wouldn’t love to learn some physics while they were there, too?

Well, we are about to find out! There is a new exhibition being opened (with brand new pictures!) on March 3rd in Preez. And I will actually give the opening speech for the liquid art half of the exhibition! I haven’t seen all the pictures yet so I can’t tell you exactly what I will be talking about, but whatever I say will definitely have to involve lots of fun physics :-)

Click for pdf

“Liquid art” by Wlodek Brühl, and how it could be used in physics teaching

Do you sometimes feel that wherever you go, you just happen to observe something that makes you think about physics? I definitely do, and that’s what happened to me again this Sunday.

#diwokiel — one week full of exciting events related to digitalization of the world

It’s currently #diwokiel, a week-long event on all kinds of aspects of digitalization. I went to a talk on his “liquid art” by Wlodek Brühl. Mr. Brühl forms sculptures out of water drops and documents those sculptures through photography. But “forming sculptures” really doesn’t begin to convey  the process through which this happens and the level of expertise and precission that is needed. Below, you see an example of one of his sculptures on the projection (for more of his absolutely breath-taking art, check out the portfolio on his website!), and the apparatus with which this kind of art is generated on the left.

As you might been guessing from the kind of setup already, there is an enormous amount of physics that goes into creating this kind of sculptures!

Using art as a hook to talk about physics

And we are back to a favorite topic of mine: How to use art in science communication!

One challenge that science communiction faces is how to reach audiences that aren’t already interested in what you want to talk about. Yes, school kids are often exposed to all kinds of topics in science communication events whether they are interested in them or not, just because their teacher decided they had to go there. But what about adults? There are a lot of people that would never knowingly attend an event that will deal with physics. Attracting them with something they are interested in — art, in this case — might be a great way to spark their interest in physics topics!

What’s the physics behind “liquid art”?

But where exactly is the physics that can be talked about? There are two main areas that jump at me: The physics of the water that is used to form the sculptures, and then the physics of capturing pictures and everything related to that.

Physics of water

As you might have guessed, my main interest lies in the physics of the water. How do you manipulate water to design exactly the kind of sculpture you want? This is not only about the exact size of drops, falling from the correct height, hitting a reservoir in the correct spot, at exactly the time you think it will, potentially additional drops with precisely calculated time lags…

In the following, I am going to give you three examples of the kind of physics I would talk about if I were to use “liquid art” in a science communication context. For all of these, there are so many nice hands-on experiments that could be offered to let people experience the effect of various parameters to show how and why it is important to consider them when creating drop sculptures. So exciting! :-)

Viscosity, or how to control the behaviour of drops

Firstly, viscosity. Having a handle on viscosity doesn’t only determine the size of the drops, but also the kind of behaviour that is displayed when the drop hits the reservoir — how deep will a drop sink, what kind of bubble will be formed, how high will the stem rise from the reservoir when surface tension drives it back up, all the good stuff.

Viscosity can be manipulated several ways: By manipulating the viscosity of water by adding starch or other substances, by using different fluids than water (which comes with additional problems, e.g. cleaning the apparatus afterwards), and by using different fluids and adding stuff to them. And then viscosity is also a function of temperature, so temperature of the whole lab (or studio) has to be controlled.

Hydrostatic pressure “plus”

The size of drops is also determined by another factor: By the hydrostatic pressure in the reservoir that feeds the drip (or valve) in combination with the opening time of said valve. There are very interesting ways to control the pressure in the reservoir that I could (and probably will ;-)) write several blog posts on!

And then it’s not only the hydrostatic pressure that is relevant: If several valves are used because water is coming from several reservoirs (for example because the water is dyed in different colors or because fluids of different viscosities are combined in one sculpture), adding pressure to a valve that is moved slightly out of the vertical lets you manipulate the parabolic trajectory the drop takes when falling, thus making it possible to drop on the spot exactly underneath a valve that just lets drops fall out vertically.

Waves, or symmetry of sculptures

And then, of course, you have to consider the vessel the water drops into. If that reservoir isn’t circular and the drop doesn’t hit it right in the middle, it is very difficult to create symmetric sculptures because the waves radiating from the point of impact (both on the surface and as pressure waves in the water) will, after being reflected by the rims of the reservoir, reach the mid point at different times, leading to an asymmetrical pressure field which will skew the whole sculpture.

Liquid art by Wlodek Brühl

Liquid art: Wlodek Brühl manipulating the apparatur he uses to create the amazing drop sculptures. Used with permission.

Physics of capturing images

And then, of course, there is all the physics of actually capturing the images. For example, Mr. Brühl mentions that the picture isn’t made by the camera, it’s made by the flash light. The way the pictures are taken that the camera’s exposure is actually fairly long, but the sharp definition is achieved because the flash only lights the sculpture for an extremely short time. And then there are things to consider like at what angle the flash lights the sculpture, how to achive the desired color effects, and many more. And of course writing the software that controlls all this!

More about this in a future post!