Will siphoning continue during free fall in an elevator?

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  • Thread starter Thread starter cragar
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Discussion Overview

The discussion revolves around the behavior of a siphon during free fall in an elevator. Participants explore the mechanics of siphoning, the role of gravity, and the effects of apparent weightlessness on fluid dynamics in this scenario.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant initially believed that siphoning would stop instantly upon entering free fall but later considered that it might continue for a short duration due to the momentum of the water.
  • Another participant argues that siphoning will not work in free fall because a pressure differential is necessary for its operation, suggesting that frictional losses will eventually halt the flow.
  • A third participant agrees with the second, stating that in free fall, objects experience apparent weightlessness, which would prevent water from flowing out of the siphon.
  • Reference is made to observations of water behavior in microgravity environments, such as on the ISS, where water appears to float rather than flow due to the lack of gravitational force.

Areas of Agreement / Disagreement

Participants generally disagree on the specifics of how siphoning behaves in free fall, with some suggesting it may continue briefly while others assert it will not function at all.

Contextual Notes

The discussion does not resolve the underlying assumptions about the mechanics of siphoning under varying gravitational conditions, nor does it clarify the exact role of friction in this context.

cragar
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Lets say I am in an elevator and I start siphoning from 2 containers. And then the elevator goes into free fall after it was already siphoning. I originally thought that it would stop siphoning instantly as it went into free fall. Now I think it will stop a little later. As the siphon is running gravity is doing the work, when it goes into free fall it is like gravity is turned off. So the force is cut but the water has momentum, so will the water flow until the friction causes the water to stop. I am thinking about this correctly?
 
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someone has to have something on this.
 
The siphon will not work in such a scenario. There has to be a pressure differential at the top of the inverted U for it to function. So yes, it will only work until frictional losses consume all the (kinetic)energy.
 
I agree. In free fall objects experience apparent weightlessness. The water would not run out of the hole in the bottom of the container.
I have seen film taken on the ISS and water is seen to 'float around' in the cabin
 

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