Why does helium change the sound of your voice?

Have you ever inhaled helium from a balloon? If so, you may have noticed that your voice becomes higher than usual. This is a funny and intriguing side effect. Here’s why it happens.

Your vocal cords vibrate when you speak or sing, much like the strings on a guitar. How fast the air passes through your vocal cords determines the pitch of your voice. Slow-moving air makes low-pitched sounds, while fast-moving air makes high-pitched sounds.

Helium is lighter than air. Therefore, when you inhale helium, it travels much more quickly across your vocal cords than oxygen, making your voice sound higher than normal.

Be careful
Though it’s fun to alter the pitch of your voice by inhaling helium, don’t overdo it. If you inhale too much, you could deprive your body of oxygen and faint. It’s perfectly safe to inhale small quantities of helium, but doing so repeatedly can have dangerous consequences.