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About water pressure

  1. Nov 11, 2009 #1
    Hello, Chitose the curious chick again.

    This is not my home work, but something I keep wondering since I watch movie 'The Abyss'.
    http://en.wikipedia.org/wiki/The_Abyss" [Broken]

    first the picture. (I draw it with photoshop, hope you guys don't get confuse)
    Untitled-1copy.jpg

    And the question.

    I wonder which zone that I can swim safely without being crush by water pressure?

    I know that 'zone A' is safe, but why? as long as I have air around and above my head, no matter how deep I am water presure can't harm me?

    I know that 'zone D' is DEAD zone, so out of the question.

    what about 'zone B' and 'zone C'?
    'zone B' have Steel panel surrounding it, 'zone C' have entire structure cover above it.

    I'm not sure if water pressure is squeeze object form up to down cause of water weight or from all direction?

    Does zone A, B and C have much different in water pressure? If i'm in 'safe zone' and point my finger through 'Dead zone', what gonna happen? can I feel light pressure to heavy pressure in just a few centimeter?

    ...................................................................
    P.S. English is not my native language, so please forgive me If i'm wrong in gramma or spelling.

    P.S.2 I can't use Technical word by myself, but I can understand when you guys useing it, don't worry
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Nov 11, 2009 #2

    Danger

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    Hi.
    Unless there's an airlock system in place, the pressure is equal in all areas. All zones are therefore equally safe. If there is an airlock, and the air pressure is lower than the external water pressure, you would have to undergo extensive decompression to re-enter the habitat. Having air around your head has nothing to do with it, other than allowing you to breathe without respirator gear.
     
  4. Nov 11, 2009 #3
    I see what Danger is saying. The pressure inside the underwater lab is high enough to keep the water from flooding, therefore your body is already accustomed to the pressure. So swim all you want, just as long as you don't swim immediately from the underwater lab's pool straight to the surface. I think the safe rise rate is somewhere between 60 - 30 feet per minute, and the deeper you are, the faster you can rise from the deepest parts. Meaning the closer you get to the surface, the slower you should go from a deep dive.
     
  5. Nov 11, 2009 #4
    So umm... If my body is accustomed to the pressure of dept level , I'll become like fish? can swim through even in zone D than?
     
  6. Nov 11, 2009 #5
    What he meant is that all areas are equally UN-safe, the pressure would kill you pretty bad.
     
  7. Nov 11, 2009 #6

    Borek

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    Just like it killed Comex divers at over 500 meters back in eigthies... Wait. They survived, so something is wrong.
     
  8. Nov 11, 2009 #7
    Fair enough, but would a diver survive at 1000 meters? I don't even think 500 meters would be very pleasant...

    "In 1992 Comex diver Theo Mavrostomos achieved a record of 701 MSW (2300 ft) in an on shore hyperbaric chamber. He took 43 days to complete the dive."

    Extremely impressive, but I would like to see him go 1km. He needed a hyperbaric chamber and ~22 days of slow progress to get to 2300ft (~700 meters). Either way it's seriously pushing the limit at the least.

    EDIT: It's awesome by the way that the OP drew a picture for us!
     
    Last edited: Nov 11, 2009
  9. Nov 11, 2009 #8

    Borek

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    Very likely at higher deeps there will be effects we are not aware of yet - I think I remember reading that at 100 atm cods lost haemoglobine from the red blood cells or something like that - so there are possible problems that we have no idea of.

    However, I was just pointing to the fact that high pressure doesn't have to be dangerous. I feel like OP has some misconceptions about the pressure and its effects.
     
  10. Nov 11, 2009 #9
    Okay, back to question. I'm bit confuse here

    I didn't dive straight from surface like comex diver.

    I'm in that facilities, and my body are accustomed to air pressure inside.

    I jump into pool in zone A, I'm sure I'm safe (assuming that I can endure to any low temparature)
    and if I'm dive to zone B, C and D

    what happen?

    which zone that water pressure gonna kill me?

    water pressure canbe so different in just a few yards?
     
  11. Nov 11, 2009 #10
    Well, we are not sure it would kill you...

    Either way the pressure is the same everywhere in your drawing. So if your gona die in one zone, all zones are deadly. (even the one with air, since the air has to push agensed the water (with equal force) to keep it from flooding into the 'research facility')

    Here is a drawing:
    http://img35.imageshack.us/img35/2478/goodtimeso.jpg [Broken]
    The idea here, is that the two arrows (of pressure) MUST be equal, so everywhere is super high pressure.
     
    Last edited by a moderator: May 4, 2017
  12. Nov 11, 2009 #11

    Danger

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    I think perhaps the problem here is that your zones are ill-defined. All water and or air at an equal depth is at equal pressure (within the parameters of your diagram). Your zones should be differentiated vertically rather than horizontally. As shown, the pressure in zone B will be higher than the pressure of zone D that is parallel to zone A.

    edit: Hi, James. You sneaked in while I was composing. Nice example. My only disagreement with it is in reference to what I just posted. The pressure won't be exactly equal at varying depths.
     
  13. Nov 11, 2009 #12

    russ_watters

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    Again, as long as you don't go up or down by more than a few yards, the pressures in all of those zones are very close to equal, so you will notice no difference in swiming from one to another.
     
  14. Nov 11, 2009 #13

    russ_watters

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    Certainly at 1000m you can no longer breather air (the oxygen at that pressure will kill you), but there is probably a mixture of gases that would be breathable.
     
  15. Nov 11, 2009 #14

    Borek

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    Yep, probably something similar to trimix. Or something not similar :wink:
     
  16. Nov 11, 2009 #15
  17. Nov 11, 2009 #16
    Oh I get it, If there are an open hole direct connect to water, air inside that room must equal with water to prevent from flooding.

    So, the movie is pure fantasy than? or 1,000m is just too deep?

    If we increase air pressure bit by bit for body that can accustomed to pressure, how high human body can take?
     
  18. Nov 11, 2009 #17

    russ_watters

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    Structurally, the human body can withstand an extremely high pressure - as long as it is equalized, it doesn't really have much effect. The problem is being able to breathe without getting the wrong combination of gases into your bloodstream. If I remember from the movie correctly, they took something like two weeks to decompress when coming to the surface to avoid the bends. No one has yet tried something like that.
     
  19. Nov 12, 2009 #18
    So... Key to servive in situation in my picture is not exactly air pressure, but how to breathe.

    than last quest.
    If we can some how adjust air compound inside, can it slove that ploblem?
     
  20. Nov 12, 2009 #19

    Borek

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    Last edited by a moderator: May 4, 2017
  21. Nov 12, 2009 #20

    Danger

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    One lesson to be learned here, as demonstrated by Borek's avatar, is don't let the glowing seaweed get on your head.
     
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