Free Fall
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From: SLC, UT
Originally Posted by espelirS2K,Jun 10 2010, 01:39 PM
I saw this posted on my facebook a few days ago.
There was a discussion going on that as you go deeper, it's easier to hold your breath, and that the only issue is when you come back up, you have to be able to spread the pressure throughout your lungs by letting the air out at a certain depth and rate.
There was a discussion going on that as you go deeper, it's easier to hold your breath, and that the only issue is when you come back up, you have to be able to spread the pressure throughout your lungs by letting the air out at a certain depth and rate.
What they were referring to was ATM (atmosphere of pressure). The air at the surface is 1 ATM. Every 33 feet you discend is referred to an ATM. At 33 feet deep (2 ATM), air is compressed into half of the density of what it was at the surface, so it only takes up half of the amount of space in your lungs/air tank/balloon, etc... At 66 feet (3 ATM) underwater, the air takes up 1/3 the space. 99 feet (4 ATM) the air takes up 1/4 the space, etc...
So, if the diver takes a full breath of air at the surface, his lungs are completely full. At 33 feet, his lung space is only half full, because the air is compressed by the water pressure. At 66 feet, the same amount of air only takes up 1/3 of his lung capacity. As he comes back up to the surface, the air will expand back to the original density, and his lungs will be "completely full"
Where the problem lies (and what the people on Facebook that were discussing this obviously didn't understand) is when you have an underwater breathing aparatus. Say, you are 66 feet deep, and you take a breath of air out of the breathing device and fill your lungs... The air is at 3 ATM, so when you ascend to the surface, the air takes up 3 times as much space as it did when you were 66 feet underwater. Since your lungs were completely full of air at 66 feet from the breath you took while at that depth, if you ascend to the surface and do not let any of that air out, the air will expand and in turn damage your lungs by stretching or rupturing them.
This is why, when you are SCUBA diving, you have to slowly breathe out while coming up to the surface, so you don't damage your lungs (the air is expanding while you come back up to the surface) With freediving, it doesn't matter because you are not taking any breaths underwater, and therefore do not have to worry about the lung damage from resurfacing.
Also, as a side note, the deeper you go, the quicker your air runs out (at the same ATM ratios)
Joined: Oct 2001
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Originally Posted by YoZUpZ,Jun 11 2010, 07:18 AM
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At 33 feet deep (2 ATM), air is compressed into half of the density of what it was at the surface, so it only takes up half of the amount of space in your lungs/air tank/balloon, etc... At 66 feet (3 ATM) underwater, the air takes up 1/3 the space. 99 feet (4 ATM) the air takes up 1/4 the space, etc...
At 33 feet deep (2 ATM), air is compressed into half of the density of what it was at the surface, so it only takes up half of the amount of space in your lungs/air tank/balloon, etc... At 66 feet (3 ATM) underwater, the air takes up 1/3 the space. 99 feet (4 ATM) the air takes up 1/4 the space, etc...
