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Happy Holidays From the Physics Buzz Team!

The Physics Buzz Team wishes all of you a wonderful holiday season. Hope you enjoy our little holiday "performance."

(Video by Brian Sanks)


Most of you probably know how the boys made their voices higher, helium. But what was in the water jug that made the girls sound a bit like Barry White? It is a gas called sulfer hexafluoride. Sometimes called "anti-helium," sulfer hexafluoride is almost 5 times as dense as air. Compare this to helium which is 7 times lighter than air. Clearly the sound of your voice must have something to do with the properties of the gas passing through your vocal cords. For an explanation of this phenomenon, watch the "extended" edition of the video. Let me note that I misspoke in my video explanation. It is the wavelength of your voice that does not change, the frequency does change based on the gas even though the wavelength stays constant.

(Video by Arlene Knowles)

If you don't feel like watching the video, here is a quick written explanation:

Sound travels at different speeds based on the type of gas its traveling through. Both the density and the weight of the molecules in the gas affect the speed. The speed of sound in sulfer hexafluoride is much slower than in air and the speed of sound in helium is much faster. Because of this, a sound with the same wavelength will have a different frequency in these different gasses. The frequency difference means your ear hears it as a higher or lower sound. The wavelength is constant so we would be just as in key (or out of it) on the fun gasses or not.

I hope you all enjoy the videos, and



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