1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Requirements for Water Spout pressure trick, at 100 scale?

  1. Mar 21, 2013 #1
    Hello this is my first post, so if I am supposed to move this to another forum section please advise I would be happy to


    As for my question, I am referencing the example of a water dispenser above, after a certain amount of flow, the water simply wont come out anymore. I assume this is because the amount of pressure/vacuum within the bottle is higher than the outside environment on the other side of the spout. Only until the lid is opened, shall the water then flow again. If someone is to look closely, they will see a level of water being suspended in mid air due to this, inside the spout.

    I am curious of the requirements to do this in something lets say 5 feet wide in diameter. Is there a way to calculate the pressure required? I am wondering the pressure needed to accomplish this and if its possible


  2. jcsd
  3. Mar 21, 2013 #2


    User Avatar
    Gold Member

    The limiting element is the size of the spout. If it is wider than a fraction of an inch, the flow will become intermittent, as air bubbles go up the spout.
  4. Mar 21, 2013 #3

    jim hardy

    User Avatar
    Science Advisor
    Gold Member

    I think it's:

    ...pressure(psi) inside LESS than pressure outside by this amount:

    .......[density of water (in lbs per cubic inch)] X [depth of water(in inches) inside above center of spigot]

    can you explain why?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Requirements for Water Spout pressure trick, at 100 scale?