Everybody knows the end-of-the-night party trick of inhaling a helium balloon to make your voice go squeaky and high. But did you know it is possible to do the opposite with another type of gas?
This video with Mythbuster’s Adam Savage from 2008 shows the effects of inhaling the gas sulfur hexafluoride.
It works in a very similar principle to the old helium trick. Since helium is six times less dense than air, it allows sound waves to travel through it much faster, hence a higher pitched sound. Sulfur hexafluoride, on the other hand, is six times denser than air meaning that sound waves travel much slower through it. See the results for yourself, although it’s certainly not as a light and hilarious as helium – think more along the lines of “The Exorcist.”
And as Adam says, don’t try this at home.