Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff, Lauren bulk bumb Here. Today's question is why does helium make our voices go all squeaky? And to answer it we have to ask three other questions. What is air, what is helium? And what is your voice? Note here at the top we cannot technically recommend inhaling helium to play with your voice, and even if we did, you
probably shouldn't take our medical advice. But if you're going to only pull from a balloon, not a helium tank, tanks contain compressed gas that will pop your lungs, and only take short breaths and make sure you get some good old regular air in between goes so that you don't suffocate. Okay, So back to our questions. First up, air. Air is a gaseous molecule soup yep. It seems real thin,
but it's chuck full of stuff when it's dry. Air is about nitrogen oxygen nearly one percent are gone, and a wee bit of a bunch of other things carbon dioxide, neon, helium, methane, etcetera. It can also contain some water, vapor and maybe zero to three percent. Your voice is the vibration of that air soup created by sound waves. When you speak, saying, or yodel, you're pushing air in your lungs out through
your throat past your vocal chords. You can vibrate, loosen, and pull taught your vocal chords in a number of ways to make a number of different frequencies of sound. Because the vibrations are periodic, meaning that their motion is repeated after an interval of time called a period, the frequencies produced by your vocal chords are harmonic. The harmonic frequencies that your vocal chords create are called your voices pitch.
You can manipulate other parts of your mouth noisemaker, your throat, jaw, cheeks, and tongue to manipulate the way those harmonic frequencies bounce around inside your head, that is, resonate before they leave your mouth. This gives more power to the frequencies as they add to each other, and it creates your voices. Timber. Timber is one of those great words that's defined by what it's not. It's not how loud your voices, and it's not your pitch. It's any other quality that's different.
If two sounds loudness and pitch are the same. Okay, all of that make more or less sense. On to helium. Helium is an element that's mixed with a little air to fill balloons because helium is less massive colloquially termed lighter than air, and thus makes balloons float in air soup. It also helps that helium is inert. It doesn't like reacting with other elements, so it's not likely to cause an explosion or catch fire or anything else that we don't like our balloons to do. And it stays a
gas at a wide range of temperatures. But yeah, it's pretty light. How light are we talking? So light? Helium's standard atomic weight is just four point zero zero three. In comparison, nitrogen and oxygen are more than three times as massive, with standard atomic weights fourteen point zero zero
seven and fifteen point nine nine nine, respectively. So when you breathe in helium instead of air, you're filling your lungs and head cavities with these wee atoms that get pushed around like all heck by sound waves like Oz's scarecrow in a mosh pit. The atoms that make up normal air don't oscillate as quickly because they're more massive,
like the tin man in a mosh pit. The practical outcome of this is that sound waves travel through helium much faster than they do through air, about three times faster. Since the sound waves are traveling faster than usual, their residences inside your head cavities occur at higher frequencies. I think of it like a pool table if you started playing with ping pong balls instead of pool balls and hit them with the same force that fly around the table,
smashing all into each other at much higher speeds. That means that less residence is happening at the lower end frequencies of your normal air driven voice, meaning the lower frequencies have less power to them, meaning that the sounds that emerge from your head cavities and out of your mouth are the higher frequencies. You sound squeaky like Donald Duck Ducks by the way, you get their squeaky quack by virtue of having a much shorter vocal tract and
less headspace for air than humans. Note that the helium doesn't change the wavelengths of the sounds emerging from your vocal cords. It doesn't affect your pitch. If you sing a particular note on regular air and then on helium it will be the same note. It will only change your timber, and specifically the timber of your vowels. Today's episode was written by Me in the Way Back for our YouTube series. I hope it wasn't terribly confusing by a audio, and also that you aren't disappointed that I
didn't suck helium while recording it. It was produced by Tyler Clang. For more on this and lots of other resonant topics, visit our home planet, how Stuff Works dot com.