Will the pressure be the same?

[superkingkong]

hi guys,

something i was cracking my brain with...

will the pressure be the same if you are at the bottom of a 80ft giant tank, above sea level and if you are in an ocean, 80ft below sea level.

any inputs?

thanks

 

[ianw2]

No.

The difference will be the pressure between sea level and the top of the tank.

The difference will not be much. You'd have to haul the tank up to a mountain top that's about 18,000 ft above sea level to drop the surrounding air pressure to 1/2 and atmosphere.

 

[do it easy]

Your depth gauge won't be able to tell the difference, but it will be slighty less in the giant tank since, presumably, the top of the tank is above sea level. Your ears might be able to feel the air pressure difference between the top of the tank and sea level.

 

[dlndavid]

Pressure is a result of depth, when you are just at sea level, but good question.
I see you are enjoying the board.

Welcome to :sblogo:

 

[The Kraken]

Yes, for all intents and purposes.
The difference will be the difference between where the top of the tank is and sea level. It becomes a miniscule matter unless, of course, you are at a 10,000 foot ASL site.
The air pressure pressing down upon you is the same as is the water, if it's salt water with the same chemical proportions of the water to which you refer.

the K

 

[The Kraken]

And a very good question, SKK . . .
. . . it's questions like this that make ScubaBoard such an interesting place !!!

Oh, and let us not forget the current barometric reading!!!

the K-Factor

 

[fisherdvm]

The difference will be 99.712% of an ATM (plus 80 ft divided by 33 times 1 ATM for the pressure exerted by the 80 ft of water). if you are on the bottom of the top tank, vs. 1 ATM plus water pressure at the bottom of the below the sea tank.

Basically, the difference is only 0.00288 of an ATM.

 

[fisherdvm]

use this calculator to figure out atmospheric pressure, air resistance, etc at altitude:

http://bpesoft.com/s/wleizero/xhac/?M=p

 

[Crazy Fingers]

Depends on how you measure the pressure. A computer, for example, measures pressure, not depth. It is just calibrated to give its answer in fsw. So if it says "80 ft" in both instances then the pressure is the same within the error of that measurement.

 

[captain]

Depends on how you measure the pressure. A computer, for example, measures pressure, not depth. It is just calibrated to give its answer in fsw. So if it says "80 ft" in both instances then the pressure is the same within the error of that measurement.

Not quite correct. Sea water is heavier than fresh water and depth gauges are calibrated for sea water but if your depth gauge read 33 feet and you were in fresh water your actual depth would be 34 feet if measured with a tape measure.