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Highest one could suck a drink up this straw?

  1. Mar 16, 2010 #1
    given a very long straw, and very strong lungs(superhuman ones), what is the highest one could suck a drink up this straw?
  2. jcsd
  3. Mar 17, 2010 #2

    Andy Resnick

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    Re: fluids

    Human lungs can develop a vacuum of about 20 inH2O, IIRC. (that means the absolute pressure is about 380 inH2O). that also means you can't be more than 20 inches underwater if you want to breathe through a straw.

    It's possible to develop more suction with your mouth, but in terms of the diaphragm, the ability to develop vacuum pressure is very limited.
  4. Mar 17, 2010 #3
    Re: fluids

    Good explanation :smile:
  5. Mar 17, 2010 #4
    Re: fluids

    It is the pressure of the atmosphere that pushes the drink up the straw.At sea level the average pressure of the atmosphere is such that it can support a column of mercury about 76 cm long.For a water based drink the greatest height would be about 10.3 metres.
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