Quiz - Skills & Environment - Diving at Altitude

[EFX]

If that's the case then why is the answer d. all of the above, which includes the choice:

a. nitrogen (sic) narcosis may occur at shallower depths.

I think I know the answer to this. I worked on it last night after I posted the above response. Boulderjohn is correct in his post, that a difference in altitude would not make any difference in getting narced due to a higher altitude.

Mathematically, working out the ppN2 of air at 6,000 ft is 0.8 atm x 0.79 = 0.63 atm. At 34 ft of fresh water the gauge pressure is another atmosphere so the absolute pressure is: 0.79 + 0.63 = 1.42 atm. taking the difference in pressure gives: 1.42 - 0.63 = 0.79.

At sea level the ppN2 of air is 0.79. At 34 ft depth the gauge pressure is still 0.79 giving 1.58 atm abs. The difference in pressure is 1.58 - 0.79 or 0.79 atm. So, there is no difference in pressure.

Choice "a" is true regardless of altitude. Divers can get narcosis at shallower depths due to their changing physiology day to day and/or diving conditions. I guess I read too much into that choice because the question was about altitude.

 

[BlueTrin]

I think I know the answer to this. I worked on it last night after I posted the above response. Boulderjohn is correct in his post, that a difference in altitude would make not make any difference in getting narced due to a higher altitude.

Mathematically, working out the ppN2 of air at 6,000 ft is 0.8 atm x 0.79 = 0.63 atm. At 34 ft of fresh water the gauge pressure is another atmosphere so the absolute pressure is: 0.79 + 0.63 = 1.42 atm. taking the difference in pressure gives: 1.42 - 0.63 = 0.79.

At sea level the ppN2 of air is 0.79. At 34 ft depth the gauge pressure is still 0.79 giving 1.58 atm abs. The difference in pressure is 1.58 - 0.79 or 0.79 atm. So, there is no difference in pressure.

Choice "a" is true regardless of altitude. Divers can get narcosis at shallower depths due to their changing physiology day to day and/or diving conditions. I guess I read too much into that choice because the question was about altitude.

If that was the intention, shouldn't it say "narcosis may occur at shallower depths" ?

Maybe I read too much into these too ...

Thanks for clarifying the intent.

 

[EFX]

During my high school and college days I got accustomed to trick questions on the exams, but PADI has outdone them all by offering trick answers to legitimate questions.

 

[BlueTrin]

During my high school and college days I got accustomed to trick questions on the exams, but PADI has outdone them all by offering trick answers to legitimate questions.

That’s my experience with PADI and BSAC exams: some questions are trying to trick you.

 

[Edward3c]

That’s my experience with PADI and BSAC exams: some questions are trying to trick you.

If you want ambiguous questions, the Institute of Internal Auditors takes some beating.

 

[TMHeimer]

During my high school and college days I got accustomed to trick questions on the exams, but PADI has outdone them all by offering trick answers to legitimate questions.

Interesting that this question (if you go with the majority that A is not correct) has no correct answer. As opposed to the old "J Valve" one which could be interpreted as having TWO correct answers. As I've spouted about, I don't think there is any excuse for these type of questions since it's just one test that probably rarely changes over time. Proof read all questions so they are absolutely clear. But, to not be a PADI basher, I did mention seeing a couple of these on the SSI Science test, and BlueTrin mentioned the same for BSAC. No excuse for any of it.
Most questions are not tricks and just ask you to regurgitate what you just read. I like that. That's what I'm real good at.

 

[EFX]

The problem with multiple guess, oops, I mean multiple choice exams is unless the answers are carefully worded the test taker doesn't have to engage in much cranial horsepower; the answer you pick is obvious from the other obviously wrong answers. So you're not engaging in any critical thinking. It appears, at least with this question, that PADI hopes to get you thinking more from all of your training rather than forcing you into tunnel-vision like thinking about altitude.

 

[boulderjohn]

So you're not engaging in any critical thinking. It appears, at least with this question, that PADI hopes to get you thinking more from all of your training rather than forcing you into tunnel-vision like thinking about altitude.

So what happens to the thinking student taking this test? Here is what likely goes through the mind of an intelligent test taker.

Choice A does not look familiar. Let me think. Did I read that somewhere? Is it true? Why would it be true? [Make it an open book test, and the student will look for the answer. It will not be found. Nothing related to this appears in the required reading (Encyclopedia of Recreational Diving]. It is likely false, but I will hold fire on it.

Choice B looks like it's right, but I have been bitten in the past by "all of the above." Yep, that's choice D, so both A and B might be right. I had better check C.

Well, yeah, choice C is true, that's what you have to do, ...but wait! That's not what the question is asking. It is not asking what you need to do; it is asking why you need to do it. The answer is supposed to finish the "because" statement, and this one does not do that. Even though the information is correct, it cannot be the correct answer.

Well, since choice C cannot be correct, then choice D cannot be correct, either.

Since I have never read anything related to Choice A and I'm pretty sure choice B is correct, that is what I am going to go with.

 

[boulderjohn]

In preparing my answer for post #58 above, I did an extensive Google search to see if there is any information anywhere related to narcosis appearing at shallower depths at altitude. I blundered into an old ScubaBoard post. The original thread was from 2002 and was on this very question. Someone resurrected it in 2015, and a wise responder closed the thread with an accurate comment:

Narcosis & Altitude

 

[TMHeimer]

So what happens to the thinking student taking this test? Here is what likely goes through the mind of an intelligent test taker.

Choice A does not look familiar. Let me think. Did I read that somewhere? Is it true? Why would it be true? [Make it an open book test, and the student will look for the answer. It will not be found. Nothing related to this appears in the required reading (Encyclopedia of Recreational Diving]. It is likely false, but I will hold fire on it.

Choice B looks like it's right, but I have been bitten in the past by "all of the above." Yep, that's choice D, so both A and B might be right. I had better check C.

Well, yeah, choice C is true, that's what you have to do, ...but wait! That's not what the question is asking. It is not asking what you need to do; it is asking why you need to do it. The answer is supposed to finish the "because" statement, and this one does not do that. Even though the information is correct, it cannot be the correct answer.

Well, since choice C cannot be correct, then choice D cannot be correct, either.

Since I have never read anything related to Choice A and I'm pretty sure choice B is correct, that is what I am going to go with.

Yeah. Great dissection. I never thought about it but that's exactly what happens.