What kind of substance should I use..

[NNenov]

I almost posted this in the physics forum but I realised that what I am ultimately looking for is a type of substance to use, and the way it behaves will be down to its chemical make-up.

 

I am not a scientist, my only knowledge is from tv documentaries. I am an animator working on a personal project and I wanted to film some liquids interacting.

 

My problem is that I want to film the same type of turbulence as what you see when you pour milk into a cup of tea. The problem is that the turbulent forms which the milk makes are on a scale far too large for the effect I am aiming for, I need the same effect but much more detailed, with intricate micro scale vortices.

This is where I get stuck, I dont need the effect to have depth, it can be a surface effect, like the turbulence on the surface of a soap bubble, but the problem is that it has be on a scale which complies with the FOV of my camera and the distance it focuses at for super macro. This means the area I have to work with effectively is about 10 x 10cm.

 

Any suggestions on the types of liquid mixtures I can use to get extremely detailed turbulence effects would be great, I was thinking that the viscosity of the liquid would play a major role, the temperature too.. I think the rainbow-like streaks you see in puddles from diesel are also an option, but they need to have very specific lighting to be filmed effectively..

Give me some suggestions and feel free to ask me to elaborate further if you need to!

 

I've just been in the chartroom and got some great suggestions from Schroedingers_hat to help me understand what I'm looking for. Its immiscible liquids, but which ones would be best, I am not sure.. Also I had pearling agent suggested to me and organic liquids..

Edited February 20, 2012 by NNenov

[Suxamethonium]

Yes. You will need to experiment with the idea a bit to get exactly what you want- but it is cheap and easy. You need a shallow pan (whatever colour/finish that works best with your camera is fine). Then pour a little water in the pan. Add methylated spirits. The alcohol in the spirits will produce a significant turbulent effect. You can experiment with food colourings, temperatures (say heating the water or spirits before hand), amounts/depth. You can even use other alcohols like isopropyl alcohol. Beware of the flammability risk, and avoid using food pans- but you could always just wash thoroughly afterwards.

 

The other option is the large scale density differential effect. You'll need a large tank of cold water and a jam jar or similar. Boil some water, colour it and pour it into the jar- put the lid on and submerge the jar in the tank. Slowly remove the lid from the jar and the hot coloured water will rise to the surface in various turbulent patterns (this is pretty much the same as the tea/coffee and milk effect- albeit reversed).

 

If you wanted imissable liquids (like oil and water) you would probably need to mechanically stir or agitate the mixture to get your effect- or rely on significant temperature differencials. Again, you would need significant experimentation to get the look you want.

 

If you want to increase the vicosity of aqueous solutions an easy way is to add sugar or glucose syrup- this also increases the density. Increasing the density of oils/solvents is harder. You might want to try solvation of solid fats (lard or butter)- but I am not sure how great that would work having never done it.

 

Happy experimenting.

[NNenov]

Thanks Suxamethonium!

That's a lot of great suggestions for me to experiment with. I have some isopropanol and white spirit, would these be good for the surface effect? (going to try that now)

 

The boiled water idea sounds really great, but ideally I'd like one of the substances to be as opaque as possible and the other transparent, so I can get interesting lighting effects. I found that food colouring is too translucent.

 

About immiscible fluids, I agree it would need to be very finely disturbed, otherwise the blobs would be way too large to get any detail.

 

That's a great idea about increasing the viscosity of the water with sugar.

 

Thanks again!

[Suxamethonium]

No worries. Um- white spirit here (australia) can also be like a shellac kind of solvent. Still experiment with it, but I don't know if it will give you the same turbulent effect as ethanol/methylated spirits.

 

As for opaqueness.. well, now things ae getting harder. You could probably work wonders with colloids, but its pretty involved chemistry requiring 'just the right amount' lol. nanotechnologist or combination with a specialist physical chemist is probably the best area to find helpful details on such chemistry.

 

You could try just using LOTS of food dye? But eventually it would dissipate. Alternatively mix large amounts of red, green/yellow and blue food dyes. This will absorb all the wavelengths effectively creating a deep black that will persist.

[NNenov]

I just tried putting a few drops of isopropanol in a shallow layer of water and it was very surprising! I've never done that before! I understand what was happening there.. But obviously they are both transparent, I tried it in some milk and got some very interesting effects indeed. Its a shame the turbulence only lasts for a few seconds.. I wonder why that is..

 

I think I'm going to stick with milk as the opaque substance, because of its colour it diffuses light off its surface defining its form rather than a black/translucent silhouette.

 

thanks again

[Appolinaria]

Contact the experts :]

 

http://paintingpolygons.blogspot.com/2008/08/fountain-peter-parks.html

 

"Into water they sprinkle yeast, dyes, solvents, and baby oil, along with other ingredients they decline to divulge. The secret of Parks' technique is an odd law of fluid dynamics: The less fluid you have, the more it behaves like a solid. The upshot is that Parks can make a dash of curry powder cascading toward the lens look like an onslaught of flaming meteorites."