Ok, don’t laugh… But before my first time underwater, I had several misconceptions regarding scuba diving. It will sound silly to the experienced divers, but I’ll confess it for the benefit of maybe other wanna-be explorers, such as I was myself, not so long ago.
Brace yourselves, here goes my embarrassing confessions, for the sake of sharing experience.
1. « I can’t go deeper than a pool bottom, my ears will burst! »
Well yes, and no, darling. Virtually no one can go deeper than 3 meters without risking their eardrums to rupture, it’s not just you, honey. Fortunately though, there’s a cure for that disease.
It’s called « equalising », and all it takes is a little blow through a pinched nose, to chase the air back into the ear canal. That way, when water exerts pressure on the outside of your eardrum, the air you just blew in will balance that pressure on the inside.
When this mechanism was shown to me, I felt like a master magician had just shared with me the secret to a magic trick.
So that’s how they do it. Equalising allows you to keep descending, without hurting your ears. Even my ears, yes. How incredible indeed.
2. « Will I need to expire through my nose all the time? »
Well, I had not been introduced to the concept of a regulator, so naturally, I thought the thing was just distributing breathable air upon inspiration, and it was left to me to exhale somewhere outside of the tube.
This is why we have two open airways on our face, right? Inhale through the mouth, exhale through the nose. No ? All the way to my first dive’s spot, I kept practicing silently: inhale through the mouth, exhale through the nose.
Oh, sweet summer child.
Introducing: the open circuit compressed air regulator. Did you know that the whole point of a regulator is to open when you breathe in, and close when you breathe out? All you have to do is breathe normally, but through the mouth only.
Well, that sounded a lot less challenging and a good deal more automatic than my own mouth-to-nose ill conceived method.
Thank you Jacques Cousteau and Emile Gagnan for that highly practical invention that is our modern regulator. Big up guys!
3. « What, you’re giving me MORE WEIGHT? But I will sink! »
If you’ve never ever been scuba diving in your life (and if you sucked at physics in highschool), you’re in for a little shock when picking up your gear: you will most likely be given extra-weight, to wear on a belt around your waist.
As a beginner, you will probably get a little more weight than actually needed, by the way.
So naturally, my first reaction was on cue with my survival instinct: hell no, I’m not jumping into a bottomless body of water with some freaking LEAD strapped on. I may not know much about scuba diving, but I know a lot about drowning: it happens when you cannot maintain yourself at the surface, which would be, for example, if I were TOO HEAVY to swim up.
So no, thank you very much, I will NOT strap 5 kilograms of lead to my waist. I’m good, thanks.
Then the instructor started to explain to me that I needed that weight to sink, because otherwise, I would float. But since I wasn’t born yesterday, I gave him a defiant stare, and proceeded to hoist up the tank & the inflatable jacket I were also supposed to be wearing before entering the water.
Now, have you ever picked up a 12L steel tank full of gas pressured at 200 bar? It is FREAKING HEAVY.
So there, I don’t need MORE weight now do I, because I’m sure to drop down like a rock wearing that thing, am I not?
No. Nope nope nope. I should have paid more attention in 10th grade, when we studied Archimede’s principle. Now what does that say again?
« An object wholly or partially immersed in a fluid will be buoyed up by a force equal to the weight of the fluid displaced by the object »
Aha. Translated into plain English, it means that : when you get into the water, you move a volume of water equivalent to your own volume. That volume of water has a weight. Weight is a force that pulls you down (it’s gravity). But that volume of water exerces a pressure that carries you up.
This is why some things float and some things sink. It’s all about volume & weight.
Alright, but back to me and my heavy tank. Surely my volume is not enough to balance all that weight? Well, as my instructor then explained to me: I was wearing a wetsuit, that is a Neoprene combinaison, made of thousands of tiny air bubbles. When we go down, the pressure rises, and compresses these bubbles, reducing my overall volume.
But at the surface, this suit basically acts as a floater. Thus the extra weight, needed to balance out all that air.
Truth be told, I was absolutely NOT convinced by the science of it all, but once in the water, I did realise that it was all true: even with that 12L tank strapped to my back and those 5 kilos around my waist, I was, in fact, floating.
I’d call it magic too, but I was told it’s physics, really.
4. « So this is a tank full of oxygen, right? »
Oxygen, or some special gas design to be breathed under water, for sure.
Wrong again. The « special gas » inside the tank is plain, normal, regular air. Like the one you’re most likely breathing right now.
If you were breathing pure oxygen, you would be feeling OVER PUMPED LOL. And at a certain pressure (1.6 bar if you must know), oxygen becomes toxic, and can trigger seizures. Not a side effect you want to experience under water, mind you.
So we’re just breathing air, like, pressured air ? Nope, just regular air at ambient pressure. So your lungs get exactly what they get at the surface: the same, breathable air, at the same pressure as your surroundings.
Wrap it up
Shall we sum it up? No special ears needed, no special breathing-skills required either, no you won’t drown and FYI, it’s air you’re breathing.
Every wonder had a simple explanation, yet it all feels magical anyway!