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Speaker 1: Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff,

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Speaker 1: Lauren bulk bumb Here. Today's question is why does helium

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Speaker 1: make our voices go all squeaky? And to answer it

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Speaker 1: we have to ask three other questions. What is air,

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Speaker 1: what is helium? And what is your voice? Note here

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Speaker 1: at the top we cannot technically recommend inhaling helium to

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Speaker 1: play with your voice, and even if we did, you

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Speaker 1: probably shouldn't take our medical advice. But if you're going

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Speaker 1: to only pull from a balloon, not a helium tank,

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Speaker 1: tanks contain compressed gas that will pop your lungs, and

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Speaker 1: only take short breaths and make sure you get some

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Speaker 1: good old regular air in between goes so that you

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Speaker 1: don't suffocate. Okay, So back to our questions. First up, air.

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Speaker 1: Air is a gaseous molecule soup yep. It seems real thin,

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Speaker 1: but it's chuck full of stuff when it's dry. Air

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Speaker 1: is about nitrogen oxygen nearly one percent are gone, and

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Speaker 1: a wee bit of a bunch of other things carbon dioxide, neon, helium, methane, etcetera.

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Speaker 1: It can also contain some water, vapor and maybe zero

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Speaker 1: to three percent. Your voice is the vibration of that

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Speaker 1: air soup created by sound waves. When you speak, saying,

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Speaker 1: or yodel, you're pushing air in your lungs out through

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Speaker 1: your throat past your vocal chords. You can vibrate, loosen,

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Speaker 1: and pull taught your vocal chords in a number of

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Speaker 1: ways to make a number of different frequencies of sound.

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Speaker 1: Because the vibrations are periodic, meaning that their motion is

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Speaker 1: repeated after an interval of time called a period, the

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Speaker 1: frequencies produced by your vocal chords are harmonic. The harmonic

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Speaker 1: frequencies that your vocal chords create are called your voices pitch.

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Speaker 1: You can manipulate other parts of your mouth noisemaker, your throat, jaw, cheeks,

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Speaker 1: and tongue to manipulate the way those harmonic frequencies bounce

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Speaker 1: around inside your head, that is, resonate before they leave

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Speaker 1: your mouth. This gives more power to the frequencies as

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Speaker 1: they add to each other, and it creates your voices. Timber.

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Speaker 1: Timber is one of those great words that's defined by

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Speaker 1: what it's not. It's not how loud your voices, and

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Speaker 1: it's not your pitch. It's any other quality that's different.

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Speaker 1: If two sounds loudness and pitch are the same. Okay,

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Speaker 1: all of that make more or less sense. On to helium.

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Speaker 1: Helium is an element that's mixed with a little air

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Speaker 1: to fill balloons because helium is less massive colloquially termed

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Speaker 1: lighter than air, and thus makes balloons float in air soup.

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Speaker 1: It also helps that helium is inert. It doesn't like

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Speaker 1: reacting with other elements, so it's not likely to cause

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Speaker 1: an explosion or catch fire or anything else that we

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Speaker 1: don't like our balloons to do. And it stays a

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Speaker 1: gas at a wide range of temperatures. But yeah, it's

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Speaker 1: pretty light. How light are we talking? So light? Helium's

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Speaker 1: standard atomic weight is just four point zero zero three.

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Speaker 1: In comparison, nitrogen and oxygen are more than three times

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Speaker 1: as massive, with standard atomic weights fourteen point zero zero

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Speaker 1: seven and fifteen point nine nine nine, respectively. So when

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Speaker 1: you breathe in helium instead of air, you're filling your

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Speaker 1: lungs and head cavities with these wee atoms that get

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Speaker 1: pushed around like all heck by sound waves like Oz's

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Speaker 1: scarecrow in a mosh pit. The atoms that make up

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Speaker 1: normal air don't oscillate as quickly because they're more massive,

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Speaker 1: like the tin man in a mosh pit. The practical

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Speaker 1: outcome of this is that sound waves travel through helium

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Speaker 1: much faster than they do through air, about three times faster.

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Speaker 1: Since the sound waves are traveling faster than usual, their

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Speaker 1: residences inside your head cavities occur at higher frequencies. I

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Speaker 1: think of it like a pool table if you started

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Speaker 1: playing with ping pong balls instead of pool balls and

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Speaker 1: hit them with the same force that fly around the table,

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Speaker 1: smashing all into each other at much higher speeds. That

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Speaker 1: means that less residence is happening at the lower end

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Speaker 1: frequencies of your normal air driven voice, meaning the lower

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Speaker 1: frequencies have less power to them, meaning that the sounds

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Speaker 1: that emerge from your head cavities and out of your

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Speaker 1: mouth are the higher frequencies. You sound squeaky like Donald

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Speaker 1: Duck Ducks by the way, you get their squeaky quack

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Speaker 1: by virtue of having a much shorter vocal tract and

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Speaker 1: less headspace for air than humans. Note that the helium

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Speaker 1: doesn't change the wavelengths of the sounds emerging from your

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Speaker 1: vocal cords. It doesn't affect your pitch. If you sing

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Speaker 1: a particular note on regular air and then on helium

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Speaker 1: it will be the same note. It will only change

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Speaker 1: your timber, and specifically the timber of your vowels. Today's

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Speaker 1: episode was written by Me in the Way Back for

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Speaker 1: our YouTube series. I hope it wasn't terribly confusing by

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Speaker 1: a audio, and also that you aren't disappointed that I

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Speaker 1: didn't suck helium while recording it. It was produced by

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Speaker 1: Tyler Clang. For more on this and lots of other

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Speaker 1: resonant topics, visit our home planet, how Stuff Works dot com.