# So, a weird question about water and oil separation

1. Jun 21, 2013

### DOB87

Well, the question is not weird, but the circumstances are.

I am not a physicist, and I am not studying physics. I am a student at a university, and quite interested in physics, but I am intentionally keeping myself away from taking any more physics classes.

I like to be able to imagine physics without the constraints of the math. I understand that the math has to add up in the end, but so far I have had an issue with it limiting my ability to think through it because I get caught up in numbers before I can see the end result. I've been able to come up with multiple theories so far that match up with currently accepted theories this way, without any previous knowledge that those theories exist.

But, working through what I am currently on, which is a question that no theory has explained thus far, requires that I understand something. It is a simple question from basic chemistry \ physics, but I cannot remember the answer, nor can I find a simple solution online.

When water separates from oil, does the rate of separation accelerate over time, or does it decelerate over time? Or does it accelerate\decelerate with certain concentrations of water vs oil, and finally reach an equilibrium?

2. Jun 21, 2013

### Staff: Mentor

What is "the rate of separation". I.e. How do you quantify separation?

Btw, physics without math is silly. The "constraints" that math imposes is that it excludes illogical theories.

3. Jun 21, 2013

### Andy Resnick

The question is not so weird- phase separations are an active area of research and have a lot of practical applications (especially in the food and consumer products industries).

Oil and water form a very simple system, the phase separation is due to buoyancy- in space, oil and water can remain well-mixed for a long period of time. On earth, adding surfactants will stabilize the emulsion. Controlling the dynamics of phase separation (to increase the shelf life of fabric softener, for example) is a multi-billion dollar industry.

Even a simple buoyancy-driven two-fluid phase separation has very complicated dynamics:

http://www.firp.ula.ve/archivos/historicos/57_Chap_Davies.pdf
http://people.umass.edu/mcclemen/FoodEmulsions2008/Presentations(PDF)/(6)Emulsion_Stability.pdf
http://www.eolss.net/Sample-Chapters/C10/E5-10-03-05.pdf

4. Jun 21, 2013

### DOB87

Sorry, I was very tired last night and had had a few drinks. I did not actually mean that I want to ignore the math. It is more an issue of, if I think too much about the math, I will get distracted and never have the ability to see the bigger picture.

I generally try to visualize a problem in my head and look at it from as many different ways as possible, and imagine myself inside, until I find a configuration that makes sense to me. Then, I try to go back and connect the dots with the math. If I can make the math work, then great, and if not, then I rethink my idea.

I know am being vague, but I'm not that great at explaining my thought processes, and the idea I am trying to grasp right now has no math to completely explain it. Water and oil will not work for me, because I was thinking of it in the wrong way.

Thanks for the links. They are very interesting. It always amazes me how complex ideas are, even when they seem so simple at first glance.

5. Jun 22, 2013