Bubbles in drinking glass

Discussion in 'Chemistry' started by Giambattista, May 23, 2009.

  1. Giambattista sssssssssssssssssssssssss sssss Valued Senior Member

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    What causes bubbles to form on the sides of a glass after water has sat for a while.

    Also wondering why sometimes in a carbonated drink, the CO2 bubbles sometimes seem to originate in a stream from one particular point in the glass, as if there is a tiny hole and the bubbles are escaping from it.
     
  2. Trippy ALEA IACTA EST Staff Member

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    10,374
    Even tap water has dissolved oxygen in it (among other gasses).
    Bubbles tend to nucleate around imperfections in the surface of the glass, whether this be some flaw in the glasswork, or simply because the glass is dirty.

    My recollection is that this tend to happen more frequently in glasses that are clean.
    I'm not 100% sure, but i'm going to go out on a limb here and hazard a guess.

    Clean glasses tend to have less 'dirt' on the inside of the glass, and therefore fewer nucleation sites for bubbles.
    I'm guessing that because of this, a principle similar to a frioping tap operates, the bubble nucleates, grows to the point where it breaks from the nucleation site, and floats up.
    My recollection is that the bubbles are smaller than the ones that stick to the inside of a glass, which may have something to do with it, and it may have something to do with the nature of the flaw that forms the nucleation site.
     
  3. Giambattista sssssssssssssssssssssssss sssss Valued Senior Member

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    4,877
    Sounds plausible to me.
    Thanks! :)
     

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