Hi Niamh, I use to love inhaling helium and speaking like Donald Duck when I was a kid! So, how does it work? Helium is much lighter than air so the speed of sound is much higher in helium. When you inhale it you increase the speed of the sound of your voice. BUT it’s not the pitch of our voice that is altered, it’s quality of the voice (we call this timbre). Basically, the fast moving higher frequency sounds have more power as they float about in your throat, and the lower frequencies get a bit lost. So our voices end up sounding flat and you talk something like Donald Duck. Is this healthy… well although it’s a lot of fun, it’s not exactly healthy. Every time you inhale pure helium, you are not inhaling oxygen, which your cells need. The lack of oxygen that comes from breathing in helium can cause fainting or even asphyxiation and death. This is especially likely if you were to breathe several balloons full of helium without getting enough oxygen in between. So be careful! Great question 🙂
Angela’s right Niamh, be careful when inhaling helium. In fact, I wouldn’t do it at all, just to be safe.
If you listen closely to your voice when you talk with helium it actually isn’t much higher really, it’s just sharper. That’s because, like Angela says, the lower frequency waves are reduced from your voice.
It’s all to do with how dense the gas is, and helium is less dense than normal air ( a mixture of mainly nitrogen and oxygen). What do you think would happen if you inhaled a gas that was heavier than air??