Would an unstable emulsion separate in the abscense of gravity? How?

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Discussion Overview

The discussion centers on the behavior of an unstable emulsion of two different liquids, such as water and oil, in the absence of gravity. Participants explore whether these liquids would separate as they do on Earth and what properties might influence their layering structure.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant suggests that in the absence of gravity, the liquids would still separate and form a spherical layered structure, questioning which liquid would be on the outside based on surface tension or other properties.
  • Another participant challenges the assumption that the liquids would separate into a layered structure, proposing that the oil might instead form globules without globally coalescing.
  • Some participants express uncertainty about the behavior of large volumes of liquid, speculating that cohesive forces might influence smaller droplets to segregate completely, while larger volumes may not interact effectively.
  • There is a suggestion that the cohesive attraction between water molecules could be satisfied by phase separation, but self-gravitation might play a role in slow coalescence over time.
  • One participant introduces the idea that small oil droplets could reach each other through Brownian motion, potentially leading to the formation of larger blobs.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether the liquids would separate into a layered structure or form globules. Multiple competing views remain regarding the behavior of the liquids in the absence of gravity.

Contextual Notes

Limitations include assumptions about the scale of the liquid volumes and the effects of surface tension and cohesive forces, which remain unresolved in the discussion.

thermodragon
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TL;DR
If you have two different liquids (water and oil for example) mixed together and free floating without gravity, will they separate as they do here on Earth? If so, what property would determine the layering structure?
If you have two different liquids (water and oil for example) mixed together and free floating without gravity, will they separate as they do here on Earth? If so, what property would determine the layering structure? I suspect they would separate, and if left undisturbed probably form a spherical layered structure. But which liquid would be on the outside and which would be on the inside? In the presence of gravity, the lower density liquid would lie on top, but in the absence of gravity is it a function of surface tension? Or some other property(ies)?
 
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Who says they will separate into a layered structure? Why wouldn't the oil just form globules without globally coalescing?
 
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I'm unsure. I suppose this can't be the case for large amounts of liquid. I imagine if you had a blob of 1 m^3 of water and two little drops of oil on either side, they wouldn't have any way of even knowing about each other. For smaller drops though, I was thinking the cohesive attraction between water molecules would squeeze the oil out of its way and make it energetically favorable to segregate the two liquids completely.
 
thermodragon said:
I'm unsure. I suppose this can't be the case for large amounts of liquid. I imagine if you had a blob of 1 m^3 of water and two little drops of oil on either side, they wouldn't have any way of even knowing about each other. For smaller drops though, I was thinking the cohesive attraction between water molecules would squeeze the oil out of its way and make it energetically favorable to segregate the two liquids completely.
I'm unsure also, but it seems to me that the cohesive attraction between water molecules has already been satisfied by the occurrence of the phase separation. But maybe self-gravitation of the fluids could contribute to very very slow coalescence and segregation over very a long period of time.
 
If there are many small oil droplets with a short distance between them, they can also reach each other by Brownian motion and form larger blobs.
 
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