Remember those birthday parties !!! when you were little, where everyone would clamber to get a helium balloon to play with? Once you got your hands on a balloon, you would slowly inhale the gas, making your voice hilariously high-pitched and squeaky. Talking like the Chipmunks or like Donald Duck was simply too hard to resist, almost as hard as not popping bubble-wrap! And yes, while I am using the past tense there, I’m perfectly aware that the temptation to inhale helium is still huge for most of us! So, my question this month is: How does helium make your voice all squeaky?
Your voice and sound
Before we delve into how helium changes your voice, it might be a good idea to do a little primer on how air makes a sound. At the back of your throat, you have a cartilaginous structure (a strong, flexible tissue, like your ears) called the larynx. For those who are curious, if you touch your throat right now, you’ll feel a bumpy and somewhat rippled lump: that’s your larynx. It’s also sometimes called the Adam’s apple, and yes, girls have one too!
Inside your larynx you have vocal cords, which are thin flaps of muscle. When you breathe in, air passes from your nose, through your larynx and towards your lungs. This doesn’t make noise because the flaps are wide open, and air easily passes through the opening. When you talk however, the muscles of your larynx contract themselves, bringing the vocal cords closer together with only a thin space between them. When air travels through the slit between the vocal cords, it makes them vibrate, which makes the surrounding air vibrate. By moving your tongue as well as the roof of your mouth and your lips, you can create recognizable sounds…which is the foundation of speech.
Deep voices versus high-pitched voices
Some people have naturally high-pitched voices, while others have much deeper voices. This is due to the length of the vocal cords themselves. When the vocal cords vibrate, they create sound. The speed at which the vocal cords vibrate determines the frequency of the sound wave, which determines the pitch of the voice. The longer your vocal cords, the lower the frequency of the resulting sound wave. Guys tend to have a lower voice than do girls, because their vocal cords are larger and thus produce sounds with lower frequencies, which produce deeper sounds.
Where does Helium fit in?
Helium is a gas (composed of He atoms) that is 6 times lighter than the air we normally breathe (which is composed of CO2, O2, N2 and traces of other gases). Because it is so much lighter than air, helium allows the sound wave to travel much faster through it than air does. This causes an increase in the frequency of the sound wave, which in turn causes the change in the pitch of the sound. In order words, the fact that the sound travels faster in helium than it does in air is what causes your voice to get all squeaky.
Okay…so we know that helium–because it’s so much lighter than air–makes your voice squeakier, but what about a denser (heavier) gas? Could it make your voice deeper? Yep, it could! If you were to breathe in sulfur hexafluoride (SF6), an inert gas 6 times heavier than air, your voice would get really, really deep. Barry White-ish deep!
One final little safety note:
Now before you go run off and inhale helium (or any other gas for that matter), I just want to remind you that while it’s fun and all, it’s not exactly healthy. Every time you inhale helium, you’re not inhaling oxygen, which means you’re getting less oxygen to your brain and other vital organs (it’s why sometimes you feel faint after breathing in helium). Also, never breathe in helium from a high-pressure tank (like those used to fill up helium balloons)! By doing this, you risk serious lung damage and brain damage. So trust me, DON’T DO IT!