Interestingly, you can have the inverse effect with heavy gasses, that will make your voice sound lower than usual. Sulfur hexafluoride is both much heavier than air and non-toxic, so it can be used in interesting ways.
You do want to ne more careful with heavy gases though as some can get stuck in the lungs. The lungs do compress when you exhale and squeeze out most but its possible for some gas to stay inside and lead to parts of the lung not getting oxygen. Its way typically only gases slightly heavier than air are used. Luckily you can have the heavy gas removed by just being upside down while breathing and medically using tubes into the lungs, the latter is almost never required.
Lying flat should prevent pooling in the lower part of the lungs too. You could alternate lying on your back and stomach to help flush it out. Breathe in, roll over, breathe out might be effective.
It also persists a bit longer than helium, as its so much heavier than any other gas in a typical breath it naturally wants to “settle” at the bottom of the gas mixture, whereas helium is pushed to the top of the mixture in full lungs. None of it stays forever, but the heavier ones take a few more lung cycles to ventilate
With a minor note that heavy gases are a bit more dangerous because of that fact. If you are upright, the want to “settle” in the bottom of your lungs. It’s not like…suicidal or anything, but you do need to be aware of it when inhaling heavier gasses even if the are effectively inert (Well, I meant thy obviously should 100% effectively inert, but you know wha I mean). The last thing you want is a heavy gas displacing enough room from oxygenated air that you have trouble breathing.
Not stupid at all. And yes! I remember as a kid I saw a scientist on David Letterman do a demonstration with Sulphur Hexafloride where he made his voice deeper. When he was done he hung upside down from a bar to clear it from his lungs.
In my previous role it was most often evident when we gave Nitrous Oxide for pain relief. I'd explain about helium making your voice sound higher because it's less dense, but NO makes your voice sound deeper.
Nitrogen and oxygen have almost the same mass, and most of the air is N2 and O2. What you can inhale is nitrous oxide, N2O, 3 atoms instead of 2 -> 50% heavier.
Nitrogen dioxide, NO2, is toxic, you'd die if that lowers your voice. There is also nitric oxide, NO, which is toxic as well (and won't lower your voice as it has about the same mass as N2 and O2).
Nitrogen and oxygen love to combine in so many different ways.
This video is cool, but I always thought that heavy gasses were a hazard because they’d sink down into your lungs and stay there as long as you were standing upright, displacing oxygen. Maybe they’re not quite as dangerous as I’d believed?
I am not a doctor, just a guy on the internet, so I can't answer that. In the video, they take the time to flush their lungs by heavily breathing to avoid problems, and it seems to work.
I'm no expert, but I think the risk is overblown. But that doesn't mean there's no risk.
Basically if you're taking full breaths, all the air is going to mix readily, whether it's heavier or lighter than air. It's not really going to "settle"
As for risks... The "oh shit" warnings in our body are triggered by higher CO2 concentrations, not lack of oxygen. So if you inhale helium or whatever, you don't necessarily get those warnings. And if you pass out, you may not be taking those full breaths that would clear out your lungs.
So don't inhale anything alone regardless of whether it's lighter or heavier than air.
Fun fact, its not C02 either. Its Carbonic acid in our Blood.
C02 mixed with water such as our blood naturally can form Carbonic acid, which is super easy to detect. It quickly dissolves into other stuff which is where most of the relevance for breathing ends.
Its the same idea though, No Oxygen means no more CO2 to replace the stuff we are expelling which means Less and less Carbonic acid forms in our blood. The stuff that is already there dissolves away, and our Acid detectors in our blood stop detecting Carbonic acid. No more warning that you are suffocating.
That is True but you can negate almost all of the risk by being diligent. Only doing one breath full at a time, breathing deeply/hyperventilating to stir the air in your lungs, and doing so for several breaths after will eliminate almost all risk. If you are really worried you can always get yourself upside down for a few breaths as well and gravity will slowly pull it out.
Sulfur Hexafluoride may be 6x heavier than air but its still a gas. Breathing itself stirs the air so it won't stay at the bottom forever. The fact your voice goes deep is proof it is leaving your lungs. Most of it will be gone after your first breath. In a bad case, if you breath really calmly and slowly it can create a pocket that blocks oxygen, but you still will have most of your Lungs working as normal. You will very likely notice the breathing problems if they occur. I can't say if it will specifically harm the bottom part of your Lungs that are not getting O2 though but I would guess it doesn't.
The Real danger is the same as with Helium, doing more than 1-2 breaths in a row without clearing it out. Our body doesn't detect oxygen at all so you won't realize you are suffocating if you do it too many times in a row. If you pass out with a lot of heavy gasses in your lungs then your reflexive breathing might not be enough to expel it in time.
This is not the correct answer, for a number of reasons.
1) As soon as the sound waves leave your mouth and travel through normal air again, the sound speed and thus the wavelengths return to normal so what you're claiming happens, would not even reach our ears.
2) "The result of the higher speed is the wavelengths of the vibrations are shorter, which makes a higher pitched sound." This is just plain wrong. For a given frequency, a faster speed of sound results in a LONGER wavelength, not shorter.
3) Our ears are not wavelength detectors. They detect frequency, vibrations per second. How fast the wave is travelling or what the wavelength is, is irrelevant. You can fill an entire room with helium, put on a speaker playing music and it will sound normal, assuming the speaker can function normally in a helium atmosphere.
What's really happening is that when you speak, your vocal chords vibrate and produce a number of harmonics, not just single frequencies. The shape of your throat will amplify certain harmonics and dampen others. By inhaling helium, you change which harmonics are amplified, favoring higher frequencies.
Why is that? Because of resonances. If you send a soundwave through a tube, it will be reflected back at the end of the tube and start interfering with the outgoing soundwaves. If the tube is a certain multiple of the wavelength, the interference will be constructive and the sound will be amplified. The longer the sound wave, the longer the tube needs to be to cause constructive interference. E.g. this is why musical instruments like pan flutes or organs produce the lowest notes with the largest tubes.
For purely illustrative purposes, assume that a sound of 1000Hz has a wavelength of 1m, so it will be amplified by a tube of 1m. Now change the gas to helium which has triple the speed of sound. Now the wavelength will be 3m and not fit in the 1m tube anymore to resonate. A 3000Hz sound will now have the correct wavelength of 1m and be amplified by the tube. So by switching to helium, we increased the frequency of the sound wave that gets amplified. This is what's happening when you have helium in your throat.
<EDIT> The result of the higher speed is the wavelengths of the vibrations move faster, which, upon the transition back to the slower air, results in a higher pitched sound.
It indeed is not the full answer. It's not even the correct answer. The higher speed of sound in helium is the root cause of the pitch change but not in the way the other person described.
Sound in water is much faster. Itsh actually so much quicker that weve never broken te sound barrier in water. Weve moved vehicles through space much faster than sound moves in water but we can move a vehicle through water at that speed because of extra drag and resistance in water as well as an issue called cavitation.
I'm no physics expert, but it appears to be because the speed of sound in fluids depends on both the density and the modulus of elasticity. The modulus of elasticity of air and helium is quite similar while for water it's >20,000 times higher.
Apparently 5 year olds these days aren’t as bright as they used to be. Brilliant explanation. Can’t be dumbed down more. Oh. Wait. ‘Cos it’s magic’ :-)
ok correct but we're comparing speed in helium vs speed in air, not some continuously changing mixture of the two, so speed in each case to be compared is constant.
The frequency stays the same. The wavelength changes because the speed changes.
Intensity also decreases because there's some partial reflections going on when waves travel through different mediums and a whole bunch of other not very ELI5-able stuff.
To expand on this answer, our throat cavity acts as a resonance chamber, amplifying certain frequencies and diminishing others. Which frequencies get amplified depends on the interaction between the geometry of the throat and the wavelength. Helium obviously doesn't change the throat geometry but it does increase the wavelength (higher speed of sounds = longer wavelength). So if previously a 1000Hz frequency was amplified the most by our throat, that peak will now shift to 3000Hz in helium since it has triple the speed of sound of normal air.
But for your voice it’s higher pitched because the sound travels easier through it than air. Since sound travels in waves think of it like dropping a ball into a pool of water and a pool of maple syrup. The syrup is much thicker and will slow the waves down. Slower sound waves means a lower pitch, and faster ones make a higher pitch.
To expand on the suffocation bit, the reason breathing helium can be dangerous is that your body detects carbon dioxide concentration, not oxygen concentration. If you breathe helium for too long, you don't get any oxygen but you are still getting rid of carbon dioxide, so your body doesn't trigger the 'hey I need to breathe' sensation you get from holding your breath. But you still aren't getting enough oxygen, so you can pass out. If you're playing with helium, just make sure you take breaks to breathe and clear your lungs in between.
I learned this as a kid at a birthday party. Trying to prolong the squeeky voice effect by taking several deep breaths of only helium (interestingly, the urge to breath is controlled by the CO2 level, not the lack of oxygen, so you feel fine while doing this). Woke up on the ground with several adults staring down at me with a mixture of concern and annoyment.
Saw this play out during a science club evening. One of the kids who volunteered for the squeaky voice thing laughed immediately on hearing his own altered voice and so wasted most of his helium. He immediately took a second lungful to try again, and while speaking using that second lungful his lips turned blue, speech slurred to a halt and he did a full length face plant.
Took seconds from ”everything here is 100.000% normal” to ”will he die? Did he break anything? Who knows how to tell if we need an ambulance?”
You were lucky. There was a woman who died this year after she took a deep breath of helium straight from the cylinder at a birthday party. Lost consciousness almost instantly and never woke up. Good way to go though.
The speed of sound in a medium -explanation does not intuitively answer why someone in not-helium will hear a squaky voice so I will elaborate:
Your voice doesn't change pitch with a lungful of helium: your vocal chords still vibrate at the same frequency. Rather, what changes is the natural frequency of your throat, so it resonates more strongly with the higher harmonics than the lower ones. The low frequency component of your voice is still there, but it is much quieter than the higher frequency component. The relative strength of these harmonics is called the 'timbre' and it is this that changes when you breathe helium.
Secondly, when a series compression waves (your voice) leave the helium in your lungs and hit the denser air, the wave train is suddenly slowed down. The wave in front is slowed first while the wave behind it is still moving fast. Then the second wave is slowed while the third is still moving fast, and so on. Doppler effect.
Your ear interprets closely bunched sound waves as a higher pitch than widely spaced waves. So when your voice originates in helium and then travels through the air to someone's ear, it sounds higher. If both you and the listener were in a room filled with helium, your voice would get to their ears faster than normal, but there would be no pitch change. You would also die but that is besides the point.
Your second point was copied almost word for word from a webpage without giving any attribution. And it's wrong. Frequency is maintained at the helium-air interface, it's the wavelength that changes. If the room were full of helium, your voice would still sound higher.
Generally if you're using a source you should cite it, but if you're quoting someones words you should really attribute them. Sure, it's just reddit, but it's also not that hard and lets people know that you aren't the one responsible for the claims (and indicates that you may not even understand them, as seems to be the case here).
To your second question, it's possible because the proportionality "constant" (the speed of sound, in this case) also changes.
Inhaling helium makes your voice sound high because sound travels faster in it, but it gives you no oxygen, so it can be dangerous and your voice returns to normal once you breathe air again.
Knock wood, then knock metal. Different sounds right? Now when you talk you’re effective “knocking” your vocal cords hundreds of times per second to make the sounds you make.
Sound just travels through air. Helium is less dense than air, so the sound changes. Just like wood and metal sound different.
Helium goes into your lungs. It does nothing because your lungs don't process helium. A short time later you die from lack of oxygen because your lungs can't process oxygen if they're full of helium.
Sounds we hear are caused by movement of what's around us (usually, air).
Notice how noises and sounds sound different under water. This happens because water is not the same as air, and sounds move differently in it.
Now notice how your voice sounds different when it comes through helium. This happens because pure helium is not the same as air, and sounds move differently in it.
By the time your silly balloon voice makes it out of your mouth, the sound has already been changed because it moved through the helium first.
In addition to the explanation about sound and densities, helium is a noble gas and is chemically inert and has no chemical reaction with you or your body, you might have trace amounts in your body at any given time from the air but it’s usually all exhaled. It can displace oxygen so while it’s not toxic it can still be dangerous in high amounts if you cannot get enough oxygen to respirate.
If the percentage of oxygen in the air is more than 21%, then your lungs move oxygen from the air into your bloodstream. (In normal air it is 21%.)
If the percentage drops due to breathing in helium, then the process reverses, and your lungs take oxygen out of your bloodstream and give it to the air.
This is wrong. Helium is used to substitute nitrogen when diving under great pressure because at high pressure nitrogen tends to have a narcotic effect, impacting judgment and the ability to operate (and ultimately live). Switching the nitrogen out for helium avoids that but people still need oxygen, the helium does not take its place.
[removed]
Interestingly, you can have the inverse effect with heavy gasses, that will make your voice sound lower than usual. Sulfur hexafluoride is both much heavier than air and non-toxic, so it can be used in interesting ways.
You do want to ne more careful with heavy gases though as some can get stuck in the lungs. The lungs do compress when you exhale and squeeze out most but its possible for some gas to stay inside and lead to parts of the lung not getting oxygen. Its way typically only gases slightly heavier than air are used. Luckily you can have the heavy gas removed by just being upside down while breathing and medically using tubes into the lungs, the latter is almost never required.
Lying flat should prevent pooling in the lower part of the lungs too. You could alternate lying on your back and stomach to help flush it out. Breathe in, roll over, breathe out might be effective.
What about doing a headstand or handstand?
Only if you sing "Old Man River" in a really deep voice as the gas escapes.
That would fall under the aforementioned category of “upside down”
It also persists a bit longer than helium, as its so much heavier than any other gas in a typical breath it naturally wants to “settle” at the bottom of the gas mixture, whereas helium is pushed to the top of the mixture in full lungs. None of it stays forever, but the heavier ones take a few more lung cycles to ventilate
With a minor note that heavy gases are a bit more dangerous because of that fact. If you are upright, the want to “settle” in the bottom of your lungs. It’s not like…suicidal or anything, but you do need to be aware of it when inhaling heavier gasses even if the are effectively inert (Well, I meant thy obviously should 100% effectively inert, but you know wha I mean). The last thing you want is a heavy gas displacing enough room from oxygenated air that you have trouble breathing.
I imagine hyperventilating for a moment would stir it up enough to push it out?
Probably deep breaths, needa squeeze that mf
Probably a stupid question but would doing a handstand then help expel that gas from your lungs faster again?
Not stupid at all. And yes! I remember as a kid I saw a scientist on David Letterman do a demonstration with Sulphur Hexafloride where he made his voice deeper. When he was done he hung upside down from a bar to clear it from his lungs.
Does that mean you could hang upside down after inhaling helium to make the effect last longer
I.... Suppose it would. It would also likely cause you to pass out while hanging upside down which 4 out of 5 doctors do not recommend.
Which five doctors? And which one is a party-pooper?
Oh the 5th one does not recommend it either but the 4 out of 5 also don't too.
RIP Mitch
Gone way too soon. Next week would've been the earliest I'd be okay with.
It does. When I demonstrate using SF6 I bend over to help clear my lungs and return to my normal voice.
Absolutely!
Yes!
It does, but it’s not necessary. The turbulence generated by breathing generally is enough to motivate it out of there.
In my previous role it was most often evident when we gave Nitrous Oxide for pain relief. I'd explain about helium making your voice sound higher because it's less dense, but NO makes your voice sound deeper.
I think NO2 is heavier that air. So it is the same effect (I think).
Nitrogen and oxygen have almost the same mass, and most of the air is N2 and O2. What you can inhale is nitrous oxide, N2O, 3 atoms instead of 2 -> 50% heavier.
Nitrogen dioxide, NO2, is toxic, you'd die if that lowers your voice. There is also nitric oxide, NO, which is toxic as well (and won't lower your voice as it has about the same mass as N2 and O2).
Nitrogen and oxygen love to combine in so many different ways.
OOOps yes, I wrote NO2 but thought N2O. Sorry.
Was going to say the opposite happens when you do nangs but you put it much better
This video is cool, but I always thought that heavy gasses were a hazard because they’d sink down into your lungs and stay there as long as you were standing upright, displacing oxygen. Maybe they’re not quite as dangerous as I’d believed?
I am not a doctor, just a guy on the internet, so I can't answer that. In the video, they take the time to flush their lungs by heavily breathing to avoid problems, and it seems to work.
I'm no expert, but I think the risk is overblown. But that doesn't mean there's no risk.
Basically if you're taking full breaths, all the air is going to mix readily, whether it's heavier or lighter than air. It's not really going to "settle"
As for risks... The "oh shit" warnings in our body are triggered by higher CO2 concentrations, not lack of oxygen. So if you inhale helium or whatever, you don't necessarily get those warnings. And if you pass out, you may not be taking those full breaths that would clear out your lungs.
So don't inhale anything alone regardless of whether it's lighter or heavier than air.
Fun fact, its not C02 either. Its Carbonic acid in our Blood.
C02 mixed with water such as our blood naturally can form Carbonic acid, which is super easy to detect. It quickly dissolves into other stuff which is where most of the relevance for breathing ends.
Its the same idea though, No Oxygen means no more CO2 to replace the stuff we are expelling which means Less and less Carbonic acid forms in our blood. The stuff that is already there dissolves away, and our Acid detectors in our blood stop detecting Carbonic acid. No more warning that you are suffocating.
That is True but you can negate almost all of the risk by being diligent. Only doing one breath full at a time, breathing deeply/hyperventilating to stir the air in your lungs, and doing so for several breaths after will eliminate almost all risk. If you are really worried you can always get yourself upside down for a few breaths as well and gravity will slowly pull it out.
Sulfur Hexafluoride may be 6x heavier than air but its still a gas. Breathing itself stirs the air so it won't stay at the bottom forever. The fact your voice goes deep is proof it is leaving your lungs. Most of it will be gone after your first breath. In a bad case, if you breath really calmly and slowly it can create a pocket that blocks oxygen, but you still will have most of your Lungs working as normal. You will very likely notice the breathing problems if they occur. I can't say if it will specifically harm the bottom part of your Lungs that are not getting O2 though but I would guess it doesn't.
The Real danger is the same as with Helium, doing more than 1-2 breaths in a row without clearing it out. Our body doesn't detect oxygen at all so you won't realize you are suffocating if you do it too many times in a row. If you pass out with a lot of heavy gasses in your lungs then your reflexive breathing might not be enough to expel it in time.
For more info, listen to it transform Adam Savage into Penn Jillette.
Resistance is futile. Behold, I am the Megabyte. I control all the technology in this room.
This is not the correct answer, for a number of reasons.
1) As soon as the sound waves leave your mouth and travel through normal air again, the sound speed and thus the wavelengths return to normal so what you're claiming happens, would not even reach our ears.
2) "The result of the higher speed is the wavelengths of the vibrations are shorter, which makes a higher pitched sound." This is just plain wrong. For a given frequency, a faster speed of sound results in a LONGER wavelength, not shorter.
3) Our ears are not wavelength detectors. They detect frequency, vibrations per second. How fast the wave is travelling or what the wavelength is, is irrelevant. You can fill an entire room with helium, put on a speaker playing music and it will sound normal, assuming the speaker can function normally in a helium atmosphere.
What's really happening is that when you speak, your vocal chords vibrate and produce a number of harmonics, not just single frequencies. The shape of your throat will amplify certain harmonics and dampen others. By inhaling helium, you change which harmonics are amplified, favoring higher frequencies.
Why is that? Because of resonances. If you send a soundwave through a tube, it will be reflected back at the end of the tube and start interfering with the outgoing soundwaves. If the tube is a certain multiple of the wavelength, the interference will be constructive and the sound will be amplified. The longer the sound wave, the longer the tube needs to be to cause constructive interference. E.g. this is why musical instruments like pan flutes or organs produce the lowest notes with the largest tubes.
For purely illustrative purposes, assume that a sound of 1000Hz has a wavelength of 1m, so it will be amplified by a tube of 1m. Now change the gas to helium which has triple the speed of sound. Now the wavelength will be 3m and not fit in the 1m tube anymore to resonate. A 3000Hz sound will now have the correct wavelength of 1m and be amplified by the tube. So by switching to helium, we increased the frequency of the sound wave that gets amplified. This is what's happening when you have helium in your throat.
<EDIT> The result of the higher speed is the wavelengths of the vibrations move faster, which, upon the transition back to the slower air, results in a higher pitched sound.
This can't be the whole story, because the room isn't full of helium so the sound still moves through air mostly.
It indeed is not the full answer. It's not even the correct answer. The higher speed of sound in helium is the root cause of the pitch change but not in the way the other person described.
Oh! So does sound move slower in water? Is that why voices sound deeper?
No, it moves much faster in water, but when you talk underwater your vocal chords are still in air.
Sound in water is much faster. Itsh actually so much quicker that weve never broken te sound barrier in water. Weve moved vehicles through space much faster than sound moves in water but we can move a vehicle through water at that speed because of extra drag and resistance in water as well as an issue called cavitation.
Like changing the playback speed on a video.
Technically changes the timbre, not the pitch. But that's because I watch QI and Stephen Fry taught me a lot :)
So why does sound travel faster in water which is more dense than air but also in helium which is less dense? Shouldn’t they be opposite?
I'm no physics expert, but it appears to be because the speed of sound in fluids depends on both the density and the modulus of elasticity. The modulus of elasticity of air and helium is quite similar while for water it's >20,000 times higher.
[deleted]
Replace the word "medium" by "things like air". Does that make it easier to understand?
See rule 4.
I enjoyed your explanation niftydog, don't mind the naysayers
Apparently 5 year olds these days aren’t as bright as they used to be. Brilliant explanation. Can’t be dumbed down more. Oh. Wait. ‘Cos it’s magic’ :-)
This is flat out wrong.
Pitch is decided by frequency, not wavelength.
Wavelength is the same no matter what you breath because it's determined by the shape/size of the resonating chamber (aka the inside of your head).
Higher wave speed means same wavelength corresponds to higher frequency, which results in higher pitch.
The entire reason helium does anything is because wave speed is different in helium.
speed/wavelength = frequency
if speed is constant wavelength and frequency each completely determine the other
"If"
Entire reason helium works is because the speed changes lol.
Wavelength and frequency are the inverse of one another, hence they are inextricably linked. If one changes, so must the other.
They are not.
wavelength = wave speed / frequency.
The entire reason helium does anything is because wave speed is different in helium.
ok correct but we're comparing speed in helium vs speed in air, not some continuously changing mixture of the two, so speed in each case to be compared is constant.
Ok, so instead of "the wavelengths are shorter" substitute "the wavelengths move faster."
The frequency shift must then happen in the transition back to air.
But what happens when sound wave exits helium mouth? The rest of the path to the ear of the listener is an old plain air
The frequency stays the same. The wavelength changes because the speed changes.
Intensity also decreases because there's some partial reflections going on when waves travel through different mediums and a whole bunch of other not very ELI5-able stuff.
Frequency of what??????? 🙄
I think this is an excellent explanation
When you breathe in helium, your voice sounds high and squeaky because helium is lighter than air.
Your vocal cords don’t change at all. Helium just makes sound travel faster in your throat and mouth, which changes how your voice sounds.
When you breathe normal air again, your voice goes back to normal.
To expand on this answer, our throat cavity acts as a resonance chamber, amplifying certain frequencies and diminishing others. Which frequencies get amplified depends on the interaction between the geometry of the throat and the wavelength. Helium obviously doesn't change the throat geometry but it does increase the wavelength (higher speed of sounds = longer wavelength). So if previously a 1000Hz frequency was amplified the most by our throat, that peak will now shift to 3000Hz in helium since it has triple the speed of sound of normal air.
You’re essentially suffocating yourself.
But for your voice it’s higher pitched because the sound travels easier through it than air. Since sound travels in waves think of it like dropping a ball into a pool of water and a pool of maple syrup. The syrup is much thicker and will slow the waves down. Slower sound waves means a lower pitch, and faster ones make a higher pitch.
To expand on the suffocation bit, the reason breathing helium can be dangerous is that your body detects carbon dioxide concentration, not oxygen concentration. If you breathe helium for too long, you don't get any oxygen but you are still getting rid of carbon dioxide, so your body doesn't trigger the 'hey I need to breathe' sensation you get from holding your breath. But you still aren't getting enough oxygen, so you can pass out. If you're playing with helium, just make sure you take breaks to breathe and clear your lungs in between.
[removed]
I learned this as a kid at a birthday party. Trying to prolong the squeeky voice effect by taking several deep breaths of only helium (interestingly, the urge to breath is controlled by the CO2 level, not the lack of oxygen, so you feel fine while doing this). Woke up on the ground with several adults staring down at me with a mixture of concern and annoyment.
Saw this play out during a science club evening. One of the kids who volunteered for the squeaky voice thing laughed immediately on hearing his own altered voice and so wasted most of his helium. He immediately took a second lungful to try again, and while speaking using that second lungful his lips turned blue, speech slurred to a halt and he did a full length face plant.
Took seconds from ”everything here is 100.000% normal” to ”will he die? Did he break anything? Who knows how to tell if we need an ambulance?”
You were lucky. There was a woman who died this year after she took a deep breath of helium straight from the cylinder at a birthday party. Lost consciousness almost instantly and never woke up. Good way to go though.
I’ve gotten dizzy a few times and stopped there lol
Annoyance
The speed of sound in a medium -explanation does not intuitively answer why someone in not-helium will hear a squaky voice so I will elaborate:
Your voice doesn't change pitch with a lungful of helium: your vocal chords still vibrate at the same frequency. Rather, what changes is the natural frequency of your throat, so it resonates more strongly with the higher harmonics than the lower ones. The low frequency component of your voice is still there, but it is much quieter than the higher frequency component. The relative strength of these harmonics is called the 'timbre' and it is this that changes when you breathe helium.
Secondly, when a series compression waves (your voice) leave the helium in your lungs and hit the denser air, the wave train is suddenly slowed down. The wave in front is slowed first while the wave behind it is still moving fast. Then the second wave is slowed while the third is still moving fast, and so on. Doppler effect.
Your ear interprets closely bunched sound waves as a higher pitch than widely spaced waves. So when your voice originates in helium and then travels through the air to someone's ear, it sounds higher. If both you and the listener were in a room filled with helium, your voice would get to their ears faster than normal, but there would be no pitch change. You would also die but that is besides the point.
Your second point was copied almost word for word from a webpage without giving any attribution. And it's wrong. Frequency is maintained at the helium-air interface, it's the wavelength that changes. If the room were full of helium, your voice would still sound higher.
So was the first point, what difference does it make?
Anyhow pray tell how would it be possible to maintain frequency while something inversely proportional to it (wavelength) changes?
Generally if you're using a source you should cite it, but if you're quoting someones words you should really attribute them. Sure, it's just reddit, but it's also not that hard and lets people know that you aren't the one responsible for the claims (and indicates that you may not even understand them, as seems to be the case here).
To your second question, it's possible because the proportionality "constant" (the speed of sound, in this case) also changes.
the first point is correct
This sounds almost plausible
Inhaling helium makes your voice sound high because sound travels faster in it, but it gives you no oxygen, so it can be dangerous and your voice returns to normal once you breathe air again.
Knock wood, then knock metal. Different sounds right? Now when you talk you’re effective “knocking” your vocal cords hundreds of times per second to make the sounds you make.
Sound just travels through air. Helium is less dense than air, so the sound changes. Just like wood and metal sound different.
Helium goes into your lungs. It does nothing because your lungs don't process helium. A short time later you die from lack of oxygen because your lungs can't process oxygen if they're full of helium.
Sounds we hear are caused by movement of what's around us (usually, air).
Notice how noises and sounds sound different under water. This happens because water is not the same as air, and sounds move differently in it.
Now notice how your voice sounds different when it comes through helium. This happens because pure helium is not the same as air, and sounds move differently in it.
By the time your silly balloon voice makes it out of your mouth, the sound has already been changed because it moved through the helium first.
In addition to the explanation about sound and densities, helium is a noble gas and is chemically inert and has no chemical reaction with you or your body, you might have trace amounts in your body at any given time from the air but it’s usually all exhaled. It can displace oxygen so while it’s not toxic it can still be dangerous in high amounts if you cannot get enough oxygen to respirate.
If the percentage of oxygen in the air is more than 21%, then your lungs move oxygen from the air into your bloodstream. (In normal air it is 21%.)
If the percentage drops due to breathing in helium, then the process reverses, and your lungs take oxygen out of your bloodstream and give it to the air.
Helium is not toxic, but it can kill you.
If you're under enough pressure you can breathe helium instead of oxygen.
This is wrong. Helium is used to substitute nitrogen when diving under great pressure because at high pressure nitrogen tends to have a narcotic effect, impacting judgment and the ability to operate (and ultimately live). Switching the nitrogen out for helium avoids that but people still need oxygen, the helium does not take its place.
Helium, like Nitrogen, is lethal if you inhale enough of it
Correction. It's lethal if you inhale only helium. It's not the quantity itself that's dangerous, it's the lack of oxygen.
It's not the helium or nitrogen that is the problem, but a lack of oxygen. You inhale mostly nitrogen all day long.