Physics Demo Number: 079

Approximate Run Time: 5 min

Breathe Helium and Speak With A  Squeaky Voice

Demo Description

Change the frequency of your voice to a higher level after breathing in helium.

Scientific Principles

  • Helium is lighter than air.

  • Hence the body's mechanism for accelerating gases in its vocal chambers gives Helium samples higher speeds than those of air.

  • The sound generated in the Helium environment has higher wave speed, as well as higher particle speed. The resonating chamber of the body has fixed wavelength producing dimensions. Hence for Helium in the lungs the frequency of vocal sound emissions must be higher than those for air in the lungs.

Equipment & Set Up

  • Helium cylinder

  • Wrench for opening cylinder valve

Equipment Location

  • Helium cylinder and wrench live in corner of prep room next to doorway  by Science Library.

Instructions

Open tank valve with wrench.

Open regulator valve and purge air from breathing tube.

Take a deep breath of air and expel it all as briskly as possible.

Put tube in mouth and inhale deeply through the mouth, with lips sealed to tube.

Start speaking in a loud voice and continue till voice returns to normal.

An effective technique is to recite several lines of poetry with normal voice, and then repeat with squeaky voice.

Or if you are musically inclined, sing a few lines of some song ( suggestion: "You are My Sunshine") with normal voice and then repeat with squeaky voice.

Be sure to close tank valve when through.
 

Notice:

The experimental procedures required for the safety of the class and the safety of the demonstrator are far too varied and difficult to be explained in detail in these write-ups.

Only suggestions as to safety procedures in the most dangerous write-ups are briefly mentioned.

These write-ups are intended only for the use of properly trained Vanderbilt science-teaching faculty.

However, the ability of web crawlers in today's world can often make these write-ups accessible to others.

So if you have stumbled upon any or all of these write-ups on the web, get assistance and supervision from your science teacher
to try any of these demonstrations.
Writeup created by David A. Burba
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