[es] - Celebs On Helium

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^{11.12.2009. u 14:30 - pre 174 meseci}

Ok gospodo, predpostavljam da je vecina vas gledala Brainiac na kanalu Discovery. Show ko show, ne preterano ozbiljan ali ipak me nesto kopka i u vezi je sa experimentom koji su izveli sa helijumom. Poznato je da kad neko udahne helijum i pocne da prica da ima nekako piskav glas. E sad, oni tvrde da je to zbog toga sto sto je on laksi od vazduha i u toj sredini zvuk brze putuje. Ja se sa tim apsolutno ne slazem. Moje misljenje o tome je da zvuk brze putuje kroz gusce sredine nego kroz redje, pa zakljucujem da se kroz helijum zvuk krece sporije nego kroz vazduh. A zvuk koji je proizveden je takav zato sto je u redjim sredinama glasnim zicama lakse da vibriraju vecom brzinom jer ne nailaze na takav otpor kao kod vazduha.Gresim ili ne?

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Igor Gajic

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Re: Celebs On Helium

^{11.12.2009. u 14:56 - pre 174 meseci}

Citat:

A more likely explanation for the increased pitch caused by inhaling helium is due to the sound producing mechanism itself. Consider the voice box modeled as a simple vibrating membrane (or perhaps a speaker cone) whose vibration acts on the ambient gas around it causing the formation of sound waves. By controlling different characteristics of the membrane (tension, shape, etc.), qualities of the created sound waves (i.e. pitch) can be controlled. In this model, the ambient gas acts as a resistance to the motion of the membrane since energy from the vibrating membrane is imparted to the gas. When the molecules composing the gas are heavy, the resistance is greater than when the molecules in the gas are light: The heavier molecules have a greater inertia for the membrane to overcome. When humans breathe helium and speak, their vocal chords, which are 'tuned' for normal atmosphere conditions, do the same things that they always do with substantially less resistance from the lighter gas. The result is that the chords will vibrate at a higher frequency.

Answered by: Joe Larsen, Ph.D. Chemistry, Rockwell Science Center, Los Angeles, CA

http://www.physlink.com/Educat...368-15C5-EE01-B910D301EBA1ABCA

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