Studying for nitrox class- please help

[dannobee]

...and know that I'll ascend with about 300 psi more than my buddy.

Don't try that with me, you'll be sucking your tank dry and I'll still have plenty in mine.

 

[pacificgal]

OK OK, be nice, as you can see my head is filled with unfamiliar stuff!
The good intentions are there, I'm trying to learn something I knew would be hard for me, and I'm trying to learn it before taking the class. I'm not reckless either, I'll get it, it's just going to take a bit longer for me because I'm totally not math-minded. I can balance my checkbook, other than that I have to really look at what the numbers, figures and equations are trying to say.
I liked the ice cream analogy, that was something put into terms I could relate to. Chocolate would have worked just as well

 

[Anti-Hero]

Maybe I'll get a lesson on Henry's Law tomorrow?

By the time I get to class Wednesday I should have them all down.
I do need to say on my behalf, however, college was a long time ago, I never took physics, and I know how to safely plan my gas for the dives I am doing, I'm just not using physics to do so, I'm using my experience and know approximately how long my gas is going to last for the dive I plan on doing, and know that I'll ascend with about 300 psi more than my buddy.

Henry's law is pretty straight forward.

Gas planning and dive calculations are basic arithmetic. The physics have already been done for you in the form of constants.

 

[diveguy1]

Maybe this will help you:

How many ATM is 60 feet?
= Use (Depth + 33) / 33 to see how many atmospheres of pressure you're at:
= (60 + 33) = 93, divided by 33 = 2.818 ATM

(A quick check - we know 66' is 3 atmospheres, so just under that = 2.818 for 60 feet)

If your air lasts 90 minutes on the surface at 1 ATM, you will consume it at a rate 2.818 faster at 60 feet, so...

90 divided by 2.818 = 31.93 minutes

 

[pacificgal]

Thanks diveguy. Let's see if I can do this myself.
How many atm's is 128 ft?
128+33/33= 4.87 atm.
If my air lasts 90 mins on the surface, 90 mins/4.87 atm=18.48 minutes?

OK, I am editing a little. 128+33/33= 4.8787878787 atm, I just rounded to 4.87, probably should have rounded to 4.88.
so, 90 mins/4.88 atm = 18.442623 mins.

 

[Jim Ernst]

Don't try that with me, you'll be sucking your tank dry and I'll still have plenty in mine.

Don't listen to him, Dan is an air sucking dog....

Joking with you Buddy, How are you Dan?

 

[diveguy1]

Thanks diveguy. Let's see if I can do this myself.
How many atm's is 128 ft?
128+33/33= 4.87 atm.
If my air lasts 90 mins on the surface, 90 mins/4.87 atm=18.48 minutes?

You got it. Of course, you'll need to factor in a possible increased air consumption rate based on cold, exertion, and leave a safe amount of air for surfacing plus a contingency amount. But that's the gist of it.

 

[pacificgal]

Thanks for the help, I'll do something like that about 5 more times and it should be securely learned.

 

[dannobee]

Don't listen to him, Dan is an air sucking dog....

Joking with you Buddy, How are you Dan?

Yeah, just call me Hoover.

I used to know a diver named Jim. I haven't seen him in the water in years. :shocked2:

 

[pacificgal]

I haven't ever even seen him near a beach! Jim!! Your fans are calling for you!!!
You'll be in Monterey the weekend of the 22nd? Maybe I can come meet you Sunday, I should be recovered by then.