Have you ever found yourself sitting at a boring fancy party? Everyone is sitting proper and discussing topics that just do not seem to interest you. Dinner was already served and the plates were taken away, the only thing remaining is the wine glasses. So out of boredom a decision is made to entertain yourself with the only thing available to you, the wineglass. Rubbing your finger around the rim you discover that it makes an eerie tone. Everyone looks your way, and you sit their embarrassed, all you were trying to do was entertain yourself.
Why is it that when you rub your finger on a wine glass it produces an eerie tone? The answer to this question is a sticking and slipping motion. When a person rubs their finger on the rim of a wine glass their finger is sticking, and then slipping on the rim over and over again. When the sticking motion is occurring the rim of the wine glass will begin to distort in the direction that your finger is moving. Once it slips the rim of the wine glass attempts to retain its original shape, but the glasses vibration stops it. This vibration is called oscillation. Oscillation is the vibrating of an object, when the vibrating of the object increases at a large state this is called resonance. Resonance is the largest vibration produced by an external stimulus. It occurs when the stimulus frequency is the same or about the same as the natural vibration frequency.
When the finger continues to rub around the rim this is causing oscillation and distortion. The finger is sticking to the rim of the wine glass and is pulling it towards the direction of motion. It will only pull so far before it slips. The rim will break free of your finger and try to retain its original shape, but it only ends up oscillating. The continuing of this motion causes a pulsation within the glasses vibration.
In slow motion or under a strobe light this oscillation can actually be witnessed. While the glass is vibrating, the air molecules around the glass are vibrating at the same frequency. The sounds that you hear are vibrating air molecules that travel by sound waves. Depending on the rims thickness, the radius of the glasses open end, if it is empty, or how much water is in the glass well determine the tone of the sound that the vibrations will produce. When water is added to the cup its resistance frequency lowers due to the waters mass. The waters mass decreases the rate at which the glass will oscillate.
oscillation. (n.d.). The American Heritage® Science Dictionary. Retrieved October 16, 2011, from Dictionary.com website: http://dictionary.reference.com/browse/oscillation
This website is good for giving definitions of words that people might not know or understand. This site was very useful to me. I now understand what the word oscillation means. I trust the information on this website because I have used it multiple times, and it was recommended to me by previous teachers.
Iflamenko. "Breaking a Wine Glass Using Resonance - YouTube." YouTube - Broadcast Yourself. 18 Oct. 2006. Web. 16 Oct. 2011. <.http://www.youtube.com/watch?v=17tqXgvCN0E&mode=related&search=>
This website is good for showing how things work. This was very useful to me because I got to see how resonance works. By watching it, it helped me to understand better. I think this is a good website to use because you can visually learn from it.
Krampf, Robert. "The Singing Glass - Video." Metacafe - Best Videos & Funny Movies. 17 Oct. 2007. Web. 16 Oct. 2011.
This website does a good job of helping people learn visually. Watching the video on this page was very helpful and educational. It helped me to understand how rubbing the rim of a wineglass can make a sound. I thought this was a good website to use because it is a great visual aid.
"TLC Cooking "How Can You Make a Wine Glass Sing?"" TLC Cooking "Food and Recipes" 2011. Web. 13 Oct. 2011.
This website broke down step for step how to make wineglasses make sound. It showed how to do the experiment, then explained what the ending results are and why. This was very useful to me because it better explained why the glass makes sound when the rims are rubbed. I’m not too sure how to feel about this website because it’s a TLC cooking website. The information was correct when compared to the other information from other sites. The information on this website was simple and easy to follow.
Catchpool, Edmund. "Vibratory Motion." The Text-Book of Sound. Vol. 1. New York City: Hinds &Nobel, 4 Cooper Institue, 1920. 1-20. Print. The Tutorial Physics.
This chapter went into detail about the motion of vibration. It talked about how the vibration causes sound, and how it travels. This chapter was very educational. The chapter helped to confirm my knowledge on vibration and sound. I found this book to be very credible, there were a lot of references in the back of the book.
HubPages Business. (Photographer). (2011). Why do tibetan singing bowls sing and make water droplets dance. [Print Photo]. Retrieved from http://janderson99.hubpages.com/hub/Why-do-Tibetan-Singing-Bowls-Sing-and-Make-Water-Droplets-Dance
LasRand Internet Marketingt. (Photographer). (n.d.). Wine glass. [Print Photo]. Retrieved from http://www.universalfunparties.com/products/other-rentals/wine-glass.jpg.php
