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Homework Help: Fluid Dynamics: quickest way to pour water out of a bottle

  1. Aug 31, 2005 #1
    I am doing a 4000 word essay on the quickest way to pour water out of a bottle and i need some help with the theory and formulas etc. Ive tried looking but this experiment isnt well documented so any help would be great!
  2. jcsd
  3. Aug 31, 2005 #2
    Well, from experience, the strawpedo works pretty well. If you stick a bendy straw in the bottle, it will come out a lot faster.

    I think this is because it equalises pressure in the bottle. Otherwise, there is a lower pressure which causes the water to slow down.

    Hopefully someone can give you a better answer.
  4. Aug 31, 2005 #3
    The "how" answer is to swirl the bottle so that a vortex forms a funnel allowing air up to the bottom of the bottle. When I have seen it demonstrated, in the lecture that you may have missed, it was done with two perrier bottles, I am not sure that was to maximise the effectiveness of the demonstration but it was very noticible that the "swirled" bottle emptied quickest.
  5. Aug 31, 2005 #4
    im aware at botht but i wanted to focus on it without using extra apparatus etc to look at angles and relationships between neck sizes
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