Morgan Freeman recently did a promo video for his show Through The Wormhole on the Science Channel. The most amazing thing about this video, he sucked in some helium and his voice changed! Here is the video!
So, why does helium causes a person’s voice to change? When your vocal cords vibrate, as when you talk or sing, the sound waves are propagated through helium instead of air. Helium is about six times lighter than air, so the sound waves travel much more quickly though helium than through air. While the geometry of your vocal cords doesn’t change, they vibrate differently in the lighter gas. The actual pitch of your voice does not change very much. However, the resonances associated with your voice are present in different proportions.
Breathing in helium illustrates how density affects the speed of sound. If you decide to breath in helium, be sure to not breathe in too much. Helium could make you lightheaded and don’t breathe in more than a few breaths of helium. Exhale fully after each breath, then take a deep breath of regular air. And please, don’t repeat the helium voice project over and over again and breathe helium directly from a compressed gas canister. That would be some very bad news!
And did you know this? The world is running out of helium! The United States uses about half of the world’s helium supply each year, lots could be going toward those helium related YouTube videos! But most of the helium used is going towards balloons. It is also used in arc welding, diving, growing silicon crystals, and as a coolant in MRI scanners. Helium is a non-renewable resource, the gas is so light, once it is leaked into the atmosphere, it’s light enough to escape the Earth’s gravitational field so it bleeds off into space, never to return. The US Government actually has the Federal Helium Reserve in Texas. And thanks to the government, helium is sold at rock bottom prices. So yes, sadly we could see helium disappear forever by 2020!
As you think about a world without helium and funny helium YouTube videos, many people have posted videos on YouTube featuring helium. Here are some of my favorites!