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!

Project which involve a falling water droplet

  1. Apr 7, 2006 #1
    I am working on this project which involve a falling water droplet on both dry and wet surfaces to figure out how is the splash is going to affect the water separation however, I have to find out the droplet size providing this info

    1) Needle diameter
    2) Water tension

    please help , if there is any derivation or formula that includes the tension and the needle diameter or whatever would help solving this problem?

    thanks in advance,
  2. jcsd
  3. Apr 7, 2006 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    Last edited by a moderator: May 2, 2017
  4. Apr 8, 2006 #3
    I founf this I am stuck I have no Idea how to get the droplet size or diameter from the relation below :

    for the droplet to detach from the needle tip, gravity has to overcome the surface
    tension. so when mg exceeds the interfacial tension at the release point the drop will
    the interfacial tension is: surface tension x 2*pi*r where r is the needle radius.
    Water at 20°C has a surface tension of 72.8 dynes/cm...
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook