This image shows the interaction of oil being introduced to water. Both are liquid, but do not mix. The molecules in the different liquids are not attracted to eachother and will always stay seperate.
The purpose of this image was to get my feet wet in finding a flow-phenomenon that I could setup as an experiment and then photograph. The resultant factors included figuring out something that may be interesting to look at and using a good camera to produce an image. The camera itself is a challenge as you must determine all the perfect settings for the particular shot, framing everything, realizing the camera is in the way of you performing the experiment, and so on. It seems simple, but there’s absolutely a fun learning curve to be had when just starting out.
In this image we can observe the effect of two liquid molecules forcefully placed in the same medium. The liquid in the mug is water, and the liquid being poured into the mug is olive oil. Because olive oil is less dense than water, it immediately floats back to the top of the water.
Archimedes’ principle can determine the force of the oil while it is under the water by,
Where,
- Fb = Force buoyancy
- ρ = density of volume
- V = volume of object
- g = force of gravity
Below is an estimation of one of the largest bubbles (~1cm^3 in volume)
Fb=ρVg
= 1000 (kg/m^3) * 0.01 (m^3) * 9.8 (m/s^2)= 98 Newtons
So there is approximately 98 Newtons of force propeling a 1cm^3 oil bubble back to the surface
I setup the experiment with the following materials:
- Olive oil
- Water
- Clear glass container (Mug)
- Camera –
- f1.4/55mm lens
- D850 (Anything capable of 1/2000 shutter speed would be fine)
- Tripod
The camera was fixed to the tripod and the pointed straight at the mug. I set the camera to ‘Ch’ which stands for ‘Continuous High’. This allows the camera to shoot as many photos in succession as the camera allows. After, I manually focused the lens to focus on the handle on the left side of the mug. This gave me a reference point in which I would target the pour of the olive oil later. I used the light-meter on my camera to determine my exposure whilst using a 1/1250 second shutter speed. A fast shutter speed such as that was chosen so that I may capture a non-blurry moment in which the oil is interacting with the water (or attempting to not interact on some level of thought). The ISO was cranked up to 4000 and the aperture was opened as wide as possible, to f1.4. The ISO caused some noise/grain of which I removed in post-editing (I will touch on that later). The f1.4 aperture allowed me to have really blurry background (called bokeh). In hindsight, a white background may have been better so that I could close the aperture in order to get more of the oil in the glass in focus. Another by-product of a wide open aperture (such as f1.4) is that your plane of focus is very narrow. In this situation at my lens’s minimum focusing distance, there is not much more than a few millimeters in the plane of focus.
Just before pouring the oil, I held down the shutter button with my left hand and then poured the oil with my right.
Function curve: 
After all was said and done, I was decently happy with the image. It had some warm colors that made it pleasing, and was interesting to look at and examine the forces that were occurring as the oil tried to normalize above the water. If I were to perform this again, I would get more light and change the background to white. This would allow more contrast and direction of the eyes to the experiment at hand. However, I think that there is much more that can be done in the world of flow-visualization and am excited to pursue other phenomena. I have one idea in mind that I’m extremely excited to get into, which is that of coincidental retro-reflective shadowgraphy.
Chris Davidoff, Flowvis.org, photo taken 9-10-2018.
29 Comments. Leave new
This is cool, I like how laminar the flow of oil into the water is, and how it breaks up into bubbles upon entry into the water. I like how the background has a similar color scheme to the subject of the photo, the mug. I think this enhances the picture rather than distracts you from the mug. Well done.
Great shot! It makes me feel like this should be an ad for a new cocktail or something. Its very well done, and while I would normally say that a solid background is better, I actually think the subtle lighting with a similar color to the oil is a good compliment to the photo. It crisp, and cropped well. Envious!
Second Place
Impressively exposed and well-focused image. The extremely shallow depth of field is pleasing to the eye and centers focus on the subject. The stream of oil going in looks extremely thin and smooth – did you inject it out of a nozzle? Did you have anything specific in mind when you choose the background? The resolution is stunning. I’d even try cropping in on the mug for a more centered composition.
The contrast and background colors are very beautiful. The effect of the two fluids rejecting to mix is clear and sharp. You could see if cropping the outsides of the glass will create a better representation of what you are trying to achieve. Good Job!
I think the lighting in this photo is super classy and the subject is very clear. Only critique I would give is trying to get the picture the first time so that there are not residual bubbles in the background.
The color in this photo is absolutely fantastic. It’s very thematic and is throughout the entire photo. The background blur is nice in that it’s not distracting at all. The oil droplets are beautifully centered and float very nicely.
Shows the flow of the oil very well. The background is an appealing color, minimally distracting and compliments the image well.
I really like the angle that you used to capture the oil penetrating the water. I also the the beer mug choice because it invokes the idea that these are beer foam bubbles coming up. Maybe crop it a little more to take out some of the background noise.
This is a beautiful image, and a great use of aperture. What was the shutter speed to stop the motion of the oil.
I really like how you captured the pouring oil in focus and without blur. You used very appealing color scheme/background. The choice of your container is really interesting.
I like the how the bubbles are shown in the picture. The fading of the background gives the picture a good look. the sharpness of the picture is amazing.
Awsome lighting composition and framing which illustrates the phenomena. Even it’s a high ISO condition but pretty few noise in the image. Pleasing color!
I like the feel of the background, it’s not too noisy to distract from the image, but it’s very pleasant. The “bubbles” forming are captured very well. How did you manage to not have any reflection on the glass?
The sharp focus is great. Great mid-action capture of the bubble. Blurred bubbles toward the back complent the picture
This is a very cool photo! I like that you were able to capture the oil bubbles as they rise back to the surface! The light is the background makes the picture look really good.
Really shows the capture of air in the oil as it is poured! The warm lighting certainly adds a mood to the photo. How did you time the pour and the capture of the photo?
The focus is effectively put on the flow and the lighting compliments the oil nicely!
I really like the narrow field of view in this photo. It makes the surface tension effects pop. I like the sharp focus and how the bubbles progress in size as they go down. The background adds to the image as well and gives it a warm feel. Good job!
The color contrast looks cool. The image presents the oil dynamic pretty well. The shape of the oil bubble is super clear. The image is sharp and great. Good job!
The colors of the image and the focus is great!
I think the physics is clear. Maybe you could crop to focus on the subject but the image of the glass mug is interesting as is too
The image is very clean and sharp. In the future consider having a solid colored background like a white wall.
This image is really clear. This clearly illustrates surface tension and other flow phenomena. The focus of this image is awesome.
Very well composed shot. The camera and focus settings seem perfect. The flow is also very clear. I think the only thing that could’ve made it more interesting is if it were a slow motion video. I want to see more of how this happened.
This is a really awesome image! I like that it appears to be in a coffee shop or something, which you wouldn’t expect to see this experiment happening in. The colors are really strong, and the clarity of the experiment/drops is really nice. I don’t think I would change anything about this image – props!
Great focus on the subject! The clear class gives a very cool artistic affect. The background is slightly busy, but the blur does not make it too distracting.
This photo is very well done! The image is close enough to show the details and the background also adds to the image in my opinion. The shutter speed and focus show the bubbles very well to demonstrate the buoyancy and shear.
This really came out nicely! Amazing to see the flow entrained in these oily spheres. Then the rich contrast just pulls the whole image together.
Very detailed pictured can see very fine parts of the image. Nice back drop to the picture makes it easy to see. The mug adds a nice element to the photo. Nice job.