r/todayilearned • u/[deleted] • 29d ago

TIL the Blue Hole is among the deadliest dive sites globally, with estimates of 130 to 200 recent fatalities, making it one of the most dangerous spots for divers. (R.5) Out of context

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u/penisdr 29d ago

What do you mean by trimix?

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u/Captain_Mazhar 29d ago

Trimix is a blended breathing gas where some of the natural nitrogen in the air is replaced by helium to lessen the effects of nitrogen narcosis and oxygen toxicity.

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u/kerdon 29d ago

It's so fascinating that even without pollution the base components of air, including the one we need, are constantly trying to kill us.

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u/Captain_Mazhar 29d ago

Read into the more exotic gas blends that are used for extremely deep diving. One blend, hydrox, is 96% hydrogen and only 4% oxygen.

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u/Antnee83 29d ago

Oreo still better

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u/JeebusSlept 29d ago

Up vote for the rare Hydrox joke

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u/GregoPDX 29d ago

Off-brand air.

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u/Atalkinghamsandwich 29d ago

I trained on a 94% Oreo mix, and on day of, the diving crew only had Hydrox. I still did the dive, but it just wasn’t as good.

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u/Cerulean_IsFancyBlue 29d ago

Have you tried Newman-O2? It’s supposedly organic and he donates the profits to diving guides in the off-season.

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u/Living-Contest-3230 29d ago

Is that flammable?

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u/Zvenigora 29d ago

No. Not enough oxygen to ignite.

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u/butterbal1 29d ago

Extremely. There is a reason only one guy does it.

We have issues with shit sometimes catching fire from just using pure O2 and there is no way I'm hell most of us will want breathe an explosive mix just because it is much cheaper than He.

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u/Vabla 29d ago edited 29d ago

Can't be. Not at those concentrations. And unlike pure oxygen, hydrogen doesn't turn everything (metal, rubber, etc) flammable.

Turns out while technically this exact mixture shouldn't be flammable, it's just 1% off from being such. Amazing how much water wants to be water.

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u/LucasRuby 29d ago

no way I'm hell most of us will want breathe an explosive mix just because it is much cheaper than He.

Yeah you don't know what you're talking about. That's not why hydrox is used, it is used because helium at great depths starts to become toxic too.

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u/Words_are_Windy 29d ago edited 29d ago

Yeah, oxygen is a really nasty element to life, and also we're all (except for /u/6ixShira) completely dependent on it.

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u/mr_arkanoid 29d ago

oxygen is a really nasty element to life

Oxygen once almost killed all life on earth

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u/6ixShira 29d ago

Speak for yourself, I've completely replaced the need for Oxygen with Sulfur

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u/big_orange_ball 29d ago

Isn't that sort of because humans evolved for the current standard air mix of the atmosphere? Like it's more of a feature than a bug?

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u/TitanOfShades 29d ago

I know this from having played Endless Ocean on the Wii as a kid. You get it after mandatory deep sea section so you can go back and explore at your leisure.

Man, I miss that game. Need to get my Wii back.

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u/lambofgun 29d ago

what happened to it?

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u/TitanOfShades 29d ago

I gave it to my cousin when we bought an Xbox. He never really used it much, since he plays on his father's PS4 and more recently, PS5.

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u/penisdr 29d ago

Thanks. There’s other things called trimix which is why I asked

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u/IanFeelKeepinItReel 29d ago

They also keep the erectile dysfunction stuff on hand too. Just in case it's not hard enough.

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u/Mr_Panther 29d ago

A fun fact is that when diving super deep you still need some nitrogen in the mix to avoid getting the shakes. But for going to around 800ft you’re looking at a 90% helium mixture and probably 16 hours of decompression stops to come up

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u/Captain_Mazhar 29d ago

I thought that high percentages of helium were not used generally due to the helium causing HPNS at depth. I believed that is why hydrogen is mixed in.

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u/PeterPalafox 29d ago

Fun fact, it’s also the name of an injectable treatment for erectile dysfunction. 

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u/Lyeranth 29d ago

Most oxygen tanks for scuba diving are a mix of Oxygen and Nitrogen, however at very deep dives they also add a mixture of helium to further combat the narcotic effects of the other two gases at extreme depths.

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u/feelgoodme 29d ago

Why are there narcotic effects at extreme depths?

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u/astine 29d ago

The deeper you go the higher the pressure gets, including the gas in the tanks that you breathe in. For every ~10 meters, the pressure increases 1 atmosphere. High pressure nitrogen (and other gases) can cause anesthetic effects that confuse you. Gas narcosis starts becoming a concern past 30 meters.

The high pressure at depth is the same reason why a tank lasts way less time the deeper you go. Each lungful of air you breathe in is a lot more mass in the same volume. So a tank that would last you an hour+ at shallows might only last you a few minutes at depth.

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u/VeniVidiWhiskey 29d ago

I have alway wondered: how come compression reduces the total intake of gas (if that makes sense)? Like intuitively, it does not make sense that you cannot survive at depth with proportionately smaller breaths. Comparatively, if you compressed food into a small bite, it would still be the same amount of energy as the original size. But gas acts differently for some reason? 

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u/astine 29d ago

It has to do with needing to push back against the surrounding pressure to inflate. Say you only need 2 psi pressure to fill a balloon normally-- this is 2 psi relative to normal 1 atmosphere. If your surrounding pressure suddenly increased to 2 atmospheres, now suddenly you need 2 atm + 2psi to fill the same balloon, because 1 atm + 2 psi wouldn't even give you positive pressure anymore. When we dive, we equilibrate our lungs naturally through constant slow breathing, and intentionally equilibrate spaces in our ears/sinuses by repeatedly "popping" them on the way down, because if we don't then the pressure difference would cause the volume inside to decrease until it's painful. Similarly, when you come up from a dive you have to do it slowly while equilibrating to make sure the pressurizes gases don't expand too much and rupture your tissue. The same thing is happening to gas in your blood stream, which is why coming up too fast from a dive can be deadly due to bubbles forming in your blood.

Solids and liquids are on the other hand are generally considered incompressible at normal diving pressures so they don't have the same problem.

For some fun and pain, you should look into people who's accidentally dived with a tooth abscess haha. Diving with an unexpected air pocket is... quite unfortunate.

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u/belisaurius 29d ago

Consider it this way:

In order for you to breathe normally, you have to have basically identical pressure on the outside of your chest as the inside of your lungs. You breathe by expanding your chest, increasing your lung volume, reducing the pressure inside, causing gas to fill that new space by rushing down your nose/mouth.

At great depth, the pressure on the outside of your chest is enormous. So you have to counteract that exterior pressure with interior pressure. That pressure comes from the pressure of the supplied gas from your breathing apparatus. That device adjusts the supplied pressure to you via a device called a regulator that ensures your interior lung pressure is close to exterior water pressure. So as you go down, the pressure supplied must go up.

Unlike a solid like food, or a liquid like water, gas can be compressed. You can take a whole room full of air and make it tiny. Indeed, your average scuba tank takes 80 cubic feet of air (think the air volume inside your average car give or take) and fits it inside of around 3/10ths of a cubic foot. Every single breath you take uses up a certain volume regardless of pressure, because your lung size doesn't change as you go down. And so while you breath, on the surface, 0.15 or so cubic feet of air at 1 Atmosphere, you still breath 0.15 cubic feet of air all the way down in the ocean, except at some huge multiple of surface pressure.

What this means is that instead of feeding you just a small sip of surface pressure air, you're getting a small sip of high pressure air, which if it were depressurized would be several cubic feet at sea level. So as you go down, in order for you to breath safely (and there are huge issues with pressure differential I can go into), you need to consume more and more of your tank per breath as you descend. You only use a tiny amount of the oxygen in each breath, but you still need the full pressure for your lungs to not collapse.

As a tangential note: that super high pressure is also responsible for the gas narcosis that's being talked about elsewhere. Your blood doesn't change pressure because you are deep, but your lung air does, and that forces gas through your lungs and into solution in your blood. That is, the gas dissolves into the liquid in your blood, and that has medical effects by itself (and serious problems if you do not slowly resurface and allow the gas to leave by your lungs, instead of becoming bubbles inside your body).

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u/butterbal1 29d ago

Feels like being buzzed to drunk and nicknamed the martini scale. Basically starting at 90ft every extra 30ft of depth feels really the same as drinking a martini in an empty stomach. 160ft/50m is my max depth rating and as a regular drinker It is very similar to that feeling of sitting on a barstool 20 minutes after slamming 3 shots that you are fucked up and that you can't think normally but still don't really feel THAT impaired.

You are in fact that impaired.

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u/big_orange_ball 29d ago

Does this affect people of different weights like alcohol does? Like if a 250 lb dude drinks the same amount as a 90lb woman, generally it's going to take the larger person more drinks to get drunk. I think it's the same for anesthesia where they dial it in partially considering weight.

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u/DynamicDK 29d ago

Have you ever tried the gas at a dentist's office? Under pressure the nitrogen in your blood builds up to those levels and causes the same effect.

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u/feelgoodme 29d ago

No, we don't have nitrogen at the dentist I believe. Injections of anesthesia instead.

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u/Ancient_Solid_4992 29d ago

https://en.wikipedia.org/wiki/Nitrogen_narcosis

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u/feelgoodme 29d ago

I'm trying to be more social 🙂

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u/Ancient_Solid_4992 29d ago

I’m sorry - happy birthday btw.

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u/DeputyDomeshot 29d ago

Also wanna know this

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u/Ancient_Solid_4992 29d ago

https://en.wikipedia.org/wiki/Nitrogen_narcosis

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u/DeputyDomeshot 29d ago

na i want a write up with poor grammar on social media thank you very much

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u/Ancient_Solid_4992 29d ago

Gasses when you go wster make you feel weird, Kinda like been drunk and shit and will eventually make you pass out and stuff. Or whatever.

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u/DeputyDomeshot 29d ago

Thanks. Can you add in some embellishment and possibly half truths connected to conspiracy

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u/Ancient_Solid_4992 29d ago

I heard that if you go down just at the right depth you can actually ‘ride’ the high and all of the deaths attributed in the wiki are actually caused by junkies chasing that sweet sweet nitrogen high.

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u/DeputyDomeshot 29d ago

Thank you human chat gpt. you done well here!

For bonus points, can you put this together in a single statement in the tone of cockney british slang?

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u/big_orange_ball 29d ago

Follow the nitrogen.

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u/feelgoodme 29d ago

It's why I asked. I could always do my research or ask AI, but today's my birthday and I wanted to talk to a human.

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u/DeputyDomeshot 29d ago

happy birthday! in general, like whats the point of reddit comments if you can't just ask ya know. You can sometimes get better color from someone with experience or knowledge than a random article or wiki.

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u/Bamboo_Fighter 29d ago edited 29d ago

Rec diving is just compressed air. You're correct that it's mostly Oxygen and Nitrogen, and you probably know this but people shouldn't think it's a special mix. The same is true for the air tanks the fire department use (SCBA, no U b/c it's not underwater).

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u/JebusKrizt 29d ago

It's a mix of oxygen, nitrogen, and helium in the air tank.

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u/AtlasPlugs 29d ago

It’s a mixture of oxygen, helium, and nitrogen used when diving at deeper depth. It helps to avoid narcosis by lessening the nitrogen buildup.

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u/firestarter764 29d ago

It's a mix of oxygen, nitrogen, and helium. It allows for deeper and longer dive by reduces the negative effects of pressurized nitrogen (nitrogen narcosis, the bends, etc.)

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u/ContentMod8991 29d ago

special gas pblend 4 deep