Chemistry and physics teachers often use a standard science demonstrate to present what happens to her voice when sound travels through a gas that’s 6 times lighter than air. Steve Spangler obtained to thinking around what happens to that exact same sound as soon as it travels through a gas that’s six times heavier 보다 air. The fun however the demonstration should be performed by a trained professional. Check out the Safety details section below.

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Sulfur hexafluoride (SF6) is inert (won’t mix with anything) and non-toxic. It have the right to do part surprising things also in tiny quantities. Except, don’t shot these at residence for two reasons: (1) you need to be trained in its exactly use and handling and, (2) SF6 is rather expensive.


SF6 is a gas it is heavier 보다 air. Choose carbon dioxide (CO2), SF6 sinks and also fills any low clues first. It can fill a sealed container to the allude where you deserve to actually feel it when you put your hands into a container filled v it.


Like CO2 , sulfur hexafluoride is dense enough to allow things to float on it, too. You deserve to fold an aluminum foil watercraft that sits best on the optimal of a great of SF6 together though it were floating on water. The pretty cool.


There is a commercial use for SF6 as a non-conductor of electricity. You deserve to see indigenous its formula that SF6 is comprised of one sulphur atom and six fluorine atoms. In this symmetry form, also the an extremely reactive fluorine is locked up tightly. That makes SF6 a perfect electrical insulator i m sorry can successfully extinguish arcs, even arcs indigenous a Taser.


Of course, the fun side of SF6 is the you have the right to safely inhale tiny quantities and also hear the temporary, yet dramatic, readjust it renders in her voice. Be breathing a little, speak normally, and your voice has dropped come a really low pitch. Again, over there are safety and security considerations based on how hefty the gas is and also what it takes to clear it out of her lungs completely.

How Does the Work

You may recognize that when you inhale a little helium (He), which is additionally an inert gas, your voice sounds like a high-pitched cartoon character. Why walk this happen? Sound waves travel lot faster with helium than they perform through constant air. Helium is much less dense than consistent air, around six times much less dense, in fact.

So, she wondering, “What inert gas is about six times heavier than the air we breathe and won’t result in fatality if I breathe that – just like CO or CO2?” Sulfur hexafluoride (SF6) is inert, not poisonous, and can affect the sound of your voice when inhaled in little quantities (Again, don’t try this at home!). As soon as SF6 is inhaled, the key of a who voice drops dramatically. The rate of sound in SF6 is way slower than it is in air. Sound travels through air at around 1100 ft/sec (335 m/s) however through SF6 it’s only around 394 ft/sec (120 m/s). ~ above the various other hand, a helium voice is heard at about 2953 ft/sec (900 m/s). It’s much faster!

As with helium, a human being trained by an skilled can breath a tiny quantity of sulfur hexafluoride without damage to demonstrate how sound travels v a very dense gas. Of course, perform not use any amount of SF6 without proper training and precautions.

Safety Information

Even despite helium is an inert gas which deserve to be inhaled briefly without threat of death, we carry out not recommend the you breath helium or any other gas besides “regular air.” The science teachers and demonstrators in the video were trained through professionals. Do not shot this experiment at house (if because that no other reason than sulfur hexafluoride (SF6) is exceptionally expensive).

Dr. Steve Harris has actually a same amount of experience using the gas in his practice. He has actually also written about SF6 extensively and understands that is properties. “It have to be for sure to be breathing SF6 using the means science teachers perform in their demos so lengthy as you carry out not fill her lungs consistently over a short duration of time. You should beware the hypoxia (oxygen deficiency) and fainting, except you will not obtain much warning because human hypoxia sensors are not very good.” the continues, “Breathe pure oxygen because that ten breaths or so before you inhale the SF6 gas. That will certainly have your lungs full of virtually 100% oxygen. That way you’ll have actually a lot of reserve versus blackout if friend go too high top top the SF6 content.”

When you’ve finished your tests, breath slowly and deeply in and out several times to aid remove the gas from your lungs. Don’t hyperventilate, just inhale and exhale deeply. SF6 needs to be moved out of her lungs a few times since it’s for this reason heavy.

Real people Applications

SF6 is used extensively in electrical power equipment. That colorless, odorless, non-flammable, and chemically stable. In ~ room temperature the does no react through anything else. Its security is what makes it valuable in electrical equipment. SF6 is a very an excellent electrical insulator and can effectively extinguish or prevent arcing due to the fact that it no conduct electricity. The an insulating and arc-quenching product in switchgear because that high- and medium-voltage applications. In electrical power systems, high- and medium-voltage switchgear is supplied to reduced off the power in instance of a fault to defend people and equipment. Electric arc strikes have the right to occur in between circuit-breaker contacts in this equipment. Breakers filled with SF6 room electrically insulating and also effectively regulate arcing.

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SF6 is mixed with argon (Ar), and also used to insulate multi-pane windows. SF6 is supplied in the metal industry when casting magnesium. Eye surgeons usage it as a cooling agent in operations. SF6 deserve to be offered as a fire extinguishing material since it is non-flammable and also cooling.