Nitrox Class Without Tables or Math...OK?

[The Kraken]

I'll state my opinion as succinctly as possible . . .

I think teaching Nitrox without learning the mathematical process is unconscionable.

the K

 

[The Chairman]

That's it!

And this makes diving safer how? You use a calculator (Or SWAG it in your head), and my students use a computer (no SWAG).

Here is the BIGGEST safety factor: computers don't get narced! The deeper you go the "stupider" you get. Your computer does not share this proclivity and will be glad to alarm you if you need that nudge to ascend. I have not learned how to set an alarm on my table!

 

[BarryNL]

And this makes diving safer how? You use a calculator (Or SWAG it in your head), and my students use a computer (no SWAG).

Here is the BIGGEST safety factor: computers don't get narced! The deeper you go the "stupider" you get. Your computer does not share this proclivity and will be glad to alarm you if you need that nudge to ascend. I have not learned how to set an alarm on my table!

Well, personally, even though I find the formulas simple I still use my computer for these reasons - plus I'm diving with the computer so its settings are the limits I'm actually using.

However, if you can't understand the simple maths - as I posted it - then you don't understand what your computer is doing. Blindly following the numbers without understanding them is also dangerous and when you make a mistake with the computer, entering the wrong mix or maxPP and you don't have a feel for the numbers, will you pick up on your mistake?

It's a bit like trying to do electronics without understanding Ohm's Law. You might be able to put the components together but you don't understand what's going on.

 

[Rick Murchison]

"Math is hard... let's go to the mall." (Barbie)
So long as you know your physics & physiology, formulae and tables well enough to know when the computer's lying, it's ok. Otherwise you're liable to get bit.
Rick

 

[MikeFerrara]

Your partial pressure is the fraction of O2 in your gas multiplied by your current pressure in ATA. -> ppO2 = FO2 * ATA.

Therefore your maximum depth in ATA is your max ppO2 divided by the FO2 of your gas.
MOD = 1.4 / FO2

That's it!

In fact, provided you work in ATAs the calculations are about the easiest you can find - a single division or multiplication. So long as you can do that and convert from ATA to depth in metres or feet you're done.

Yes, it's that simple and I don't remember ever teaching a nitrox class where students had a hard time with it either.

The most common problem I had teaching nitrox (or any other coned course) was that I'd get students in the water and find out they couldn't get through my simple skill preassessment. It often required a significant amount of confined water work before I felt it was reasonably safe to move to OW and the training dives at hand. The industry is fixing this problem by no longer requireing dives in the class.

Now they're removing everything else...What's left? "set your computer up this way and stop when it beeps at you"? Can't they get that from their computer instruction manual?

I never thought that it made much sense to have a whole seperate class for nitrox. But now, without the dives or teaching the finner points that simplify and increase the power of dive planning, the whole thing seems really sensless. Sure they still need to know that they need to limit their max PPO2 and their total exposure but do you need a class for that? Just add a couple of sentences to the computer instruction manual. Make it an extra paragraph if you want them to have a list of oxtox signs and symptoms. It's probably already in some instruction manuals.

I have an idea. Just have them fax you a copy of a reciept showing that they have purchased a nitrox comuter and a release saying that they have read it and just send them a card. A better idea would be to just do away with the card because it's demonstrably meaningless.

 

[Rick Inman]

The most common problem I had teaching nitrox (or any other coned course) was that I'd get students in the water and find out they couldn't get through my simple skill preassessment.

You'd think that the diving requirement would remain, due to the increased importance of good buoyancy skills, when oxtox due to higher O2 enters into the diving equation.

Wait a minute, that's right. 1.4ppo. Lots of room there. Never mind.

Note: For those of you strictly computer trained, ignore that 1.4ppo thing I just said. Don't worry, your computer will beep at you.

 

[Daner]

Sounds like we have alot of people here using an abacus or a slide rule to 'calculate' these precious formulas. According to a lot of logic here (of those opposed to this course), if you don't use the oldest available tool then you cannot possibly learn the material. Now that seems ludicrous.

I have not taken a NitrOx course (yet) and mathematical formulas do not scare me but if there is a better or easier way of accomplishing the same goal, I am all for that.

In my experiences with courses (both SCUBA and non-SCUBA), I find there is far too much time spent on crunching numbers and not enough time spent on the actual material (theories/laws/whatever) that is truely important. I can see me sitting in a NitrOx course with my instructor (who is thorough and traditional) spending 80% of the class time on grade 10 math skills (which today kids learn in grade 5) for those who are mathematically challenged and 20% on NitrOx relevant material.

Keep striving for improvement NetDoc!

 

[serambin]

It's more than that. Lets not forget that some agencies allow children to dive before they've even finished learning their multiplication tables. A little math can indeed get in the way of industry objectives. . .

That might be a little tough. Most of us (on this board) want to know how it works and therefore how to protect ourselves best. Having said that, each time you fly on a jet, or step on the brakes in your car, you're mostly in the hands of a computer. If you rely on your dive computer alone, one could argue for a backup computer for safety.

I still calulate my group manually as a check during the SI, made a dive plan, and reviewed my computer for validation.

Stan

 

[Kim]

It's been a while since my course, and I don't know how it is for agencies other than IANTD, but I had to do a theoretical exam and work out a few EADs, MODs, best mix etc. Don't you have to demonstrate that you know the theory to get the card? Isn't there a test with all of the agencies?

 

[BarryNL]

It's been a while since my course, and I don't know how it is for agencies other than IANTD, but I had to do a theoretical exam and work out a few EADs, MODs, best mix etc. Don't you have to demonstrate that you know the theory to get the card? Isn't there a test with all of the agencies?

Yes, but the PADI pass mark is 80% so you can get all those wrong and still pass.