Title Under Header

.

Monday, January 10, 2011

Helium & Sulfur hexafluoride ~ Makes Your Voice Lower & Higher

Don't try this because there may be very dangerous side effects... instead... watch the experiments done by others shown in video links below.

Helium & Sulfur hexafluoride ~ Gases That Makes Your Voice Higher & Lower

Helium (makes voice higher)
Biological effects ~ Effect of helium on a human voice
The speed of sound in helium is nearly three times the speed of sound in air. Because the fundamental frequency of a gas-filled cavity is proportional to the speed of sound in the gas, when helium is inhaled there is a corresponding increase in the pitches of the resonant frequencies of the vocal tract.[4][100] This causes a reedy, duck-like vocal quality. (The opposite effect, lowering frequencies, can be obtained by inhaling a dense gas such as sulfur hexafluoride.) Inhaling helium can be dangerous if done to excess, since helium is a simple asphyxiant and so displaces oxygen needed for normal respiration.[4][101] Breathing pure helium continuously causes death by asphyxiation within minutes. Inhaling helium directly from pressurized cylinders is extremely dangerous, as the high flow rate can result in barotrauma, fatally rupturing lung tissue.[101][102] However, death caused by helium is rare, with only two fatalities reported between 2000 and 2004 in the United States.[102] However there have been two cases in 2010, one in the USA[103] in January and another in Northern Ireland in November[104]. At high pressures (more than about 20 atm or two MPa), a mixture of helium and oxygen (heliox) can lead to high pressure nervous syndrome, a sort of reverse-anesthetic effect; adding a small amount of nitrogen to the mixture can alleviate the problem.[105][106]

Sulfur hexafluoride (makes voice lower)
Physiological effects and precautions
Another effect is the gas's ability to alter vocal sound waves. The gas can be inhaled in a small, safe amount and cause the breather's voice to sound very deep. This is due to the gas's large molar mass. Unlike helium, which has a molar mass of about 4 grams/mol, SF6 has a molar mass of about 146 g/mol, and the velocity of sound through the gas is 0.44 times the speed of sound in air due to the large inertia of a SF6 molecule. For comparison, the molar mass of air, which is about 80% nitrogen and 20% oxygen, is approximately 30 g/mol. Inhalation of SF6 causes a lowering of the timbre, or frequency of the formants, of the vocal tract, by contrast with inhalation of helium, which raises it.[9] Other gases such as Freon or xenon have a similar effect, although xenon is generally not used for such demonstrations due to its high cost and anaesthetic properties. It is possible to safely breathe heavy gases such as xenon or sulfur hexafluoride as long as they include a 20% mixture of oxygen. The lungs mix the gases very effectively and rapidly so that the heavy gases are purged along with the oxygen and do not accumulate at the bottom of the lungs.[10] There is, however, a danger associated with any heavy gas in large quantities: it may sit invisibly in a container, and if a person enters a container filled with an odorless, colorless gas, they may find themselves breathing it unknowingly.[11]

~~~
Video Links:
~~~
Mythbusters - Helium and Sulfur Hexafluoride
~~~
~~~
Sulfur Hexafluoride Blooper
~~~
~~~
My voice after inhaling Sulfur Hexafluoride
http://www.youtube.com/watch?v=vcVMjGRzDz8
~~~

~~~
Labels:
Vocal, 
~~~

No comments: