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!

Diamond + oil

  1. Jun 20, 2009 #1
    I read on the news that when you place oil from behind your ear onto the diamond. You can stick it to the window and the adhesive power will be so strong that you can place a metal pincet on it.

    Any explanation?

    http://www.standaard.be/video/videoPlayer.aspx?cat=1&subcat=1&videoId=352871 [Broken]
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Jun 22, 2009 #2
    If I were to speculate, the reason why may be due to the surface of the diamond. Since a diamond is very hard and compact, the surface would be very smooth and not have a lot of crevices or cracks (on a microscopic scale).

    Because of that, if the diamond were to be covered in oil and stuck to a wall, the oil would cause an air-tight seal that would be very hard to break due to the smooth surface of the diamond.
  4. Jun 22, 2009 #3

    Andy Resnick

    User Avatar
    Science Advisor
    Education Advisor

    I don't know what a 'pincet' is, but thin layers of fluid can adhere two flat objects together with surprising strength. For example, one must be careful when handling 'gauge blocks' so that they do not adhere and become useless. This is also a problem (but a slightly different mechanism) with very clean surfaces that contact in vacuum- they can essentially weld themselves together.

    The origin is the film pressure or disjoining pressure of the fluid- the extreme curvature of the edges of the film implies a very high pressure difference between the fluid and outside, and the thin film resists tearing.
    Last edited by a moderator: May 4, 2017
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook