Why do fluid drops are sperical?

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Discussion Overview

The discussion centers around the shape of fluid drops in air, specifically why they tend to be spherical rather than ellipsoidal, despite the pressure exerted by the surrounding air. The scope includes theoretical considerations of fluid dynamics and surface tension, as well as potential experimental observations with different fluids.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant questions why fluid drops are not ellipsoidal, suggesting that air pressure should influence their shape.
  • Another participant asserts that surface tension balances aerodynamic forces, leading to the predominance of spherical shapes in drops.
  • A later reply proposes that if a fluid with low surface tension were placed deep underwater, it might form an ellipsoidal bubble, indicating a conditional relationship between surface tension and shape.
  • Another participant notes that surface tension of the surrounding water still affects the shape of bubbles, suggesting that the context of the fluid's environment is significant.
  • There is curiosity expressed about the shapes of raindrops made from different materials, such as organic solvents or superfluid helium, indicating interest in variations beyond standard water drops.

Areas of Agreement / Disagreement

Participants express differing views on the influence of surface tension and pressure on the shape of fluid drops, with no consensus reached on the primary factors determining drop shape.

Contextual Notes

Participants mention the role of surface tension and environmental conditions, but the discussion lacks detailed exploration of the mathematical relationships or specific definitions of terms used.

Who May Find This Useful

Individuals interested in fluid dynamics, surface tension effects, and experimental physics may find this discussion relevant.

fluidistic
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Hi,
I'm almost sure that this question frequently appears and have been asked thousands of times and if so, then excuse me and I'll be OK if you give me a link to such a thread.
I don't understand why fluid drops in air are not ellipsoidal since the air makes pressure vertically on everything submerged in it. The same apply for air's bubbles in water. Water makes pressure vertically and so the bubble should get an ellipsoidal form, but it doesn't.
Thank you!
 
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Surface tension balances the aerodynamic forces - mostly surface tension wins so the drops are almost spherical.
 
mgb_phys said:
Surface tension balances the aerodynamic forces - mostly surface tension wins so the drops are almost spherical.

Thanks SO much!
If I find a fluid that has a little surface tension and I put it say in deep ocean (more than 10km under water surface) then I'd likely get an ellipsoidal bubble. :smile: if I understand well.
 
Well there is still the surface tension of the water because there is a surface around the bubble.
It would be interesting to know what shape 'raindrops' of other materials formed in air - say organic solvents or superfluid helium!
 

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