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And I thought a bubble was a bubble! — Parallax Forums

And I thought a bubble was a bubble!

skylightskylight Posts: 1,915
edited 2013-08-08 23:20 in General Discussion
Having just watched a documentary about bubbles and their usefulness as a tool for scientists I was shocked at one point where a patient was having ultrasound and in order to enhance the pictures they injected air into the patients bloodstream!!
My immediate thought was "What about the bends?"
after the programme i did a bit of research and found that the medical industry has produced special types of microbubbles that cannot coalesce and produce a potentially dangerous larger bubble.
Fascinating stuff.

http://depts.washington.edu/fluidlab/theses/cethesis.pdf

Comments

  • Heater.Heater. Posts: 21,230
    edited 2013-08-07 14:38
    I'm really glad all those bubbles in my Guinness don't coalesce and produce a potentially dangerous larger bubble:)
  • skylightskylight Posts: 1,915
    edited 2013-08-07 14:46
    Heater. wrote: »
    I'm really glad all those bubbles in my Guiness don't coalesce and produce a potentially dangerous larger bubble:)
    :lol: Funnily enough they talked about another drink Champagne and how the speed and size of the bubbles make the taste more or less enhanced, the shape of the glass flute is essential and they even etch the glass in a special way to make the bubbles form.
    On the medical side if you read the thesis in the #1 post The bubbles can be vibrated with ultrasound to help break up blood clots, a similar idea was used in the documentary to make a water spout change from just plain water to an ultrasound bubble filled spout that could clean,
    It could mean the end of needing hot water for cleaning, saving energy bills.
  • Martin_HMartin_H Posts: 4,051
    edited 2013-08-07 17:18
    Heater. wrote: »
    I'm really glad all those bubbles in my Guiness don't coalesce and produce a potentially dangerous larger bubble:)

    Ah Guiness, I love the creamy foam the nitrogen bubbles produce, and the slightly tart pucker from soured Guiness that they pasteurize and add back into the brew.
  • Heater.Heater. Posts: 21,230
    edited 2013-08-08 00:07
    Here is a nice video by Professor Moriarty of Nottingham university about bubbles and the physics of Guinness. http://www.youtube.com/watch?v=qNBTygWcy0s
    Yes that is his name. Wonderful Belfast accent as well.
  • skylightskylight Posts: 1,915
    edited 2013-08-08 02:44
    Well Holmes, it doesn't take much detective work to work out why they still don't understand all the theory behind it, not surprising with all that Guinness around the research tends to fall by the wayside. :lol:
  • Heater.Heater. Posts: 21,230
    edited 2013-08-08 03:08
    Back when I was studying physics I invented a little drinking game:

    1) A round of beers and a packet of salted peanuts is bought for two or more guys. Make that nice lively beer but not too lively.
    2) Each guy drops three of the salted peanuts into his beer.
    3) The peanuts sink to the bottom initially.
    4) Slowly bubbles nucleate and grow on the peanuts and they will lift the peanuts up to the top of the beer.
    5) On reaching the surface the bubbles detach from the peanuts which then sink back down to the bottom.
    6) We are back to 4) again so this whole process repeats many times, peanuts migrating magically up and down in the beer. This is a "beer engine".

    The game is then that the guy whose "beer engine" stops first has to buy the next round.

    Whist this was an interesting game to play once or twice sadly it did not catch on. Probably because in involves a lot of time watching your beers rather than actually drinking them:)

    A slightly more advanced version of the game that gets you to drinking the beer quicker is "beer engine racing" where you time the migrations of the peanuts and the guy with the slowest one buys the next round. But that involves the complication of timing and the ensuing arguments over the results.

    I was quite taken with my, admittedly accidental, discovery of the "beer engine". I suspect the salt on the peanuts is important for it's operation, stimulating the nucleation.

    Not sure if it works with unsalted. This calls for further ...err...research. I'll be back in a bit...


    Edit: See here for some nice examples of bubble nucleation and theory: http://en.wikipedia.org/wiki/Nucleation
  • skylightskylight Posts: 1,915
    edited 2013-08-08 03:47
    Interesting game :smile: perhaps the oil on the surface of the peanut helped?
    Nice interesting article thanks
  • GadgetmanGadgetman Posts: 2,436
    edited 2013-08-08 23:20
    It's definitely the salt.

    Remember the 'Soda and Candy' fountain trick?
    Mythbusters did an episode on that, and found that salt had a lot of 'nucleation sites'...
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