Question: why does our voice go high if we swollow helium

Zoe Vance answered on 11 Mar 2025:

Helium is less dense than air so the sound waves that your vocal cords make can vibrate much faster when they move through it, making them higher frequency so your voice sounds high pitched. It doesn’t do anything to your actual vocal cords (they still vibrate at the same frequency) which is why your voice goes back to normal once there isn’t any helium around them any more.