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Dancing Pint Glass

  1. Dec 28, 2011 #1
    "Dancing" Pint Glass

    Not sure if this really should go here, as I don't personally think it was anything supernatural, though I do lack an explanation for it.

    I'd called into a local pub for a quick drink after work a few weeks back. It was pretty empty, just myself, the barmaid, and an older guy, and we were all standing at the bar.

    After a while, I noticed that an empty glass on the bar top near me was "dancing."

    It was making short, almost deliberate looking movements, drifting forward a little way before sharply turning direction, then doing the same, seemingly moving of its own violition. I pointed it out to the barmaid, who got kind of excited and said it was the ghost of the old landlord, who "slammed doors".

    There were no obvious breezes, and when I got the barmaid to give me another empty glass and set it down beside the first, it sadly refused to join in the dance with its friend. When I eventually put a finger on the top of the dancing glass to stop it moving, it refused to start up again. I felt kind of bad that I'd spoiled its fun.

    I'm assuming it was being moved by either vibrations or tiny air currents I couldn't feel, but the glass I tried to make dance with it was unaffected, and I tried several times to "reanimate" the first without success.

    I'd basically like to know any suggestions to what caused it so that I can replicate the effect - it was a curiously relaxing sight.
     
  2. jcsd
  3. Dec 28, 2011 #2

    Evo

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    Staff: Mentor

    Re: "Dancing" Pint Glass

    Quite common, a film of water on the bar will cause the movement, seen it a number of times.

    http://www.madsci.org/posts/archives/2000-03/952562476.Ph.r.html
     
    Last edited: Dec 28, 2011
  4. Dec 28, 2011 #3
    Re: "Dancing" Pint Glass

    A thin film of water (Or beer, etc) under the glass would act to float the glass along, mostly based on the shape and texture of the bar, nibbling along the path of least resistance. Small amounts of liquid would escape, further changing the shape of the supporting film and paths to follow.

    This would explain little seemingly random movements, twists, etc.
     
  5. Dec 28, 2011 #4
    Re: "Dancing" Pint Glass

    Wow, thanks for the rapid replies!

    So all I should have to do to replicate this is to dampen the bottom of a glass, and "launch" it gently onto the table top, so the water cushions it from the table surface?

    I am going to practice this. Being able to make glasses dance to my whims sounds like a good trick to have in the repertoire.
     
  6. Dec 28, 2011 #5

    Evo

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    Staff: Mentor

    Re: "Dancing" Pint Glass

    It'll take practice to do it at will. Mostly I'll place a wet glass on a counter and then have to stop it before it goes off the edge. I've never tried to do it on purpose.
     
  7. Dec 28, 2011 #6
    Re: "Dancing" Pint Glass

    I just tried it...its easier to wet the table top, and put the glass down onto it, rather than wetting the glass.
     
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