Ok, really it's similar to the reason that a balloon full of it will float in air... or water for that matter. It's less dense than air, which is basically an 80/20 Nitrogen/Oxygen mix (well like 78/19/3 where the 3 is all the other crap).
Here's there weird part. It doesn't. Helium does not change the pitch of your voice. Wait what.....?
Back to the density thing. I won't get into too much chemistry here, but know this: helium is less dense than nitrogen & oxygen. Air is 97% of both of these... so helium is less dense than air. Sound will travel faster in a less dense gas... again sciency stuff. So sound travels faster in helium and to us this means... nothing (sort of). Why? Because the gas that is actually propagating the sound [the stuff the noise is moving through] is still regular air. So WTF?
Your voice comes from your vocal cords (or more accurately folds) vibrating. Can we all agree on that? You remember that trick where you hold the blade of grass between your thumbs and blow? Kind of like that.
Like the noise the blade of grass makes, the pitch of the voice is dependent on how fast the folds vibrate. This is determined by the tension on the folds and the pressure of gas moving through. Not what kind of gas, so your folds are still vibrating as they would with air.
Ok, awesome. But why does it sound like that when I do helium stuff???? Timbre. It changes the timbre of your voice. Partials and fundamentals man. The higher speed of sound in helium accentuates the higher partials your voice naturally makes and masks the lower ones. If that's enough for you, skip to after the video. If not, read on here. And here with many big words.
One last thing. You can die fooling around with this stuff. Don't do it. Seriously. I mean look what happened to these idiots:
Well, if you're still here after that I suppose I should give you some show related stuff!
It's showtime you crazy, crazy people. Yes. Thira will be at the Cabooze in Minneapolis at 8:30, this Saturday March 12th.
Seriously, it's gonna be a blast. We'll be playing 4 tracks of the new EP. Hell yeah we are. 'Cuz we're Thira that's why.
We've still got just a couple of presale tickets available (literally, we only have about 2 left) so shoot us an email and we'll get it figured out. I mean, $2 is $2 is $2 is 8 quarters is 200 pennies is 24 pesos is 166 yen but only 1.44 euro. Thus concludes today's lesson.
Until then, be sure to check out the rest of our videos on our youtube channel: www.youtube.com/thiraband and eat your vegtables. A diet high in fiber makes you more effective in the pit. SCIENCE!!!