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Homework Help: Theory behind the singing wine glass

  1. Jun 8, 2012 #1
    1. The problem statement, all variables and given/known data
    So I have been set a task to design an experiment revolving around a singing wine glass. This is to rub a finger along the rim of the wine glass to produce a tone. At the moment I am considering to do 2 variables, the volume of liquid within the wine glass and the density of the liquid. We are measuring the frequency and seeing what variable changes the frequency the most.
    Now onto my problem, I am required to do background research behind this topic; however, I currently don't know what to research and my teacher wants a lot of background information that is relevant to the topic.

    2. Relevant equations
    -None that I know of at the moment.-

    3. The attempt at a solution
    I am thinking about doing some research on the glass and how it vibrates to produce the sound and the different densities of the liquids. But, the density would change depending on the day so I can't do much research on it.

    Any help as to what I can research about this topic is greatly appreciated thanks.
  2. jcsd
  3. Jun 8, 2012 #2

    Simon Bridge

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    You want to investigate the effect of the size of the wine glass too.
    Is the volume of the glass as important as the circumference of the rim? In what way?
    The note also depends on how full the glass is - is it the volume of the liquid or just how high it is? (Compare blowing in a bottle to make a tone.)

    How the density of the liquid affects it is a good idea - you may want to check how the density varies from day to day. I'm betting: not much. Perhaps you can compare water with syrup with putty - to the same levels?

    It helps to have some idea about how the tone is formed - what is doing the important vibrating? Is it the whole glass or is just part of it setting the tone?

    What level are you doing this research at?

    Have you seen:
  4. Jun 9, 2012 #3
    The task sheet says not to do too many variables as we'll run out of time in each lesson of experimentation. It hasn't been set clear but I'll say there's 4-5 lessons for experiments and each lesson is about 1 hour. So I'm thinking of letting the wine glasses all be the same, so the tone is entirely dependent on the %volume and density.

    For the liquids being used:
    water as control
    sea water

    The volumes to which the glass would be filled to hasn't been decided yet but I'd say increase of 20% volume each time.

    And this research is at year 12 high school level, but still has to have complex and challenging concepts involved.

    By the way, thanks for the reply :]
  5. Jun 9, 2012 #4

    Simon Bridge

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    Oh OK so you keep the wine glass the same and study effect of how much filled and what sort of liquid. Microphone and oscilloscope? You may want to check with air (empty glass) as well.

    That link I gave you has some good information and also more links to background information. Since the background research is part of the exercise, I cannot actually give you the info you want.

    Basically you want to end up with some sort of theory to test ... you are allowed to be wrong but you do need to be able to justify the theory.
  6. Jun 9, 2012 #5
    Ahh yeah I was planning on using an empty glass as well. And thanks for the information, its a great help
    I just wasn't sure what topics to research that's all just needed a little hint, cheers :]
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