Why Does Your Voice Get Higher When You Inhale Helium? - Big Questions (Ep. 11)

Hi, I'm Craig. My vocal cords are made up of two vibrating mucous membranes

and this is Mental Floss on YouTube. Today I'm going to answer Bridget Klein's big question

Why does your voice get higher when you inhale helium? Let's get started

First, let's do a refresher on sound. I'm sure you remember this from your mini science classes

so this is going to be the crash course version. Put simply, we're able to hear sound thanks to vibrations that travel through air. Those vibrations

forms sound waves. Here's an example of sound. The speed of sound is how fast sound waves travel. The speed depends on the medium that the sound waves are going through

Sound frequency is how often that mediums particles vibrate as the wave travels through it

Frequency affects the pitch of a sound. This all coming back to you, right

Great. When we speak, we must produce vibrations. This happens with our vocal chords, which are two vibrating mucous membranes stretched across the larynx

Air travels from your lungs to your larynx, which makes your mucous membrane vibrate

It's the frequency of this vibration that affects the pitch and... and volume of your voice

Then the sound travels through your vocal track, which is made up of your pharynx mouth and nasal cavities Here air vibrates affecting your voice timber Timber is basically the sound character and quality It also a way to indicate that you are chopping a tree down Now let talk about helium Helium speed of sound is three times faster than the speed of sound in air

This is because helium atoms have a lower mass than the mass of oxygen and nitrogen atoms

Think about how balloons with helium rise. That's because helium is less dense than air

It's atoms move quicker, which means it can carry sound quicker. Let's imagine you just inhaled helium

When you talk through those vibrating vocal cords I mentioned earlier, the frequency is going to be the same

So the pitch of your voice is also going to be the same. voice is also going to be the same. Your voice is altered thanks to the vocal tract where

helium is causing the sound waves to be faster. Basically, inhaling helium affects the

timber of your voice, not the pitch, like many people believe. Now it's time for my lecture

Inhaling helium can cause death by asphyxiation, which has happened before. I do not recommend

trying this at home or at any public establishment. That said, you can reverse this phenomenon

by inhaling denser gases that you might have laying around like xenon or sulfur hexafluoride

Who doesn't have that? I have sulfur hexafluoride parties all the time, but you really shouldn't do that

Mental Floss on YouTube, made with the help of these lovely mucous membranes. If you have a big question, you would like answered, leave it in the comments below

See you next week