Quiz - Physics - Water and Heat

[Pedro Burrito]

And now for a change, no RDP today, instead ... Physics!

From the Physics section of the PADI Dive Theory Exam:

Because the heat capacity of water is thousands of times greater than air, water conducts heat more than ___ times better than air.

a. 100

b. 24

c. 20

d. 4

I will post a daily question from my exams to help newer divers and to encourage more experienced divers to interact gracefully and helpfully with the newer divers.

Reminder - this is a post in the Basic Forum and it is a green zone. Please be nice and on topic.

Thank you for your patience while we try to give people something to discuss other than Covid-19 and/or Politics. I will post the answer covered by the spoiler tag later today.

 

[Vitesse2l]

My very basic school physics says this is a bit of a trick question. I spent some time with google anyway and refreshed my memory before voting. Cheating? Probably.

Thanks Pedro B.

 

[BlueTrin]

My very basic school physics says this is a bit of a trick question. I spent some time with google anyway and refreshed my memory before voting. Cheating? Probably.

Thanks Pedro B.

Um Pedro B. ... is that some kind of code ?
*wink* *wink*

 

[Vitesse2l]

Um Pedro B. ... is that some kind of code ?
*wink* *wink*

Haha! It's just that I can't pronounce Burrito.

 

[loosenit2]

This is an interesting question because it allows Room for confused room mixing of common examples. The heat transfer properties of water vs air are easily calculated, and are often done by mechanical engineers. However calculating the rate of heat loss in the human body in air vs water is much more variable, some studies go as high as 40 times faster. Various scuba texts go back and forth between basic heat transference and applied transference in the human body.

 

[HKGuns]

Suffice it to say I turn blue after spending time in an 81 degree pool.

This one should go down the Rabbit hole fairly quickly once the professors wake up.

 

[tursiops]

This is an interesting question because it allows Room for confused room mixing of common examples. The heat transfer properties of water vs air are easily calculated, and are often done by mechanical engineers. However calculating the rate of heat loss in the human body in air vs water is much more variable, some studies go as high as 40 times faster. Various scuba texts go back and forth between basic heat transference and applied transference in the human body.

But the question is not about heat loss from the human body.....

 

[CT-Rich]

The effective difference between 20x and 24x is almost moot or 100x for that matter. You can die of Hypothermia in 70F. Proper exposure gear.

 

[loosenit2]

But the question is not about heat loss from the human body.....

exactly, but it is easy for one to confuse the numbers because both figures are used often in texts.

 

[Scraps]

I don’t know whether I got this right.

I answered based on my memory.

Then I checked my PADI open water manual and found it says “about” the number that agrees with my memory.

But then I checked the PADI Encyclopedia of Recreational Diving, and it says “more than” the number in the OW manual.

So I guess my answer is somewhere between “about right” and too low.