Ask A Scientist Chemistry Archive

Question:
Why does one have a squeaky voice after inhaling helium from balloon?
 chris l balsano

Answer:
Chris,
 
Helium is an inert gas which we can inhale, at least briefly,
without dying. (I wouldnt suggest trying this with hydrogen for example.)
 
The mechanism is that, first, sound is produced by our vocal cords
through vibration.  The air around our vocal cords is vibrated,
and we interpret this as sound.  Helium is a gas much lighter
that the mixture of gases we call 'air', which is comprised mostly
of nitrogen, oxygen, and a few lesser gases. Our vocal cords
can vibrate faster in a helium environment than in a heavier
'air' environment.  The faster vibration causes the higher pitch we hear.
As the helium is depleted and replaced by regular air, the 'squeakiness'
disappears.
 
Naturally you do not want to inhale helium regularly.  Our health
is best on a diet of 'regular air'.
 
Ric
Thanks for using NEWTON!