Long snorkel breathing

[Nemrod]

The air pressure in the hose is 14.7 psi, assuming sea level. The pressure at four feet is atmospheric (14.7) plus the equivilent of four feet of water. Approximately 33 feet of seawater equals one atmosphere. At four feet the pressure your body sees is several psi greater than at the surface. The lungs do not "suck" air, the diaphram muscles increase and decrease the size of the lung cavity and atmospheric or ambient pressure simply fills the space with air. No, there is simply no way for numerous physical reasons presumably covered in Jr High science that a human cannot overcome even several psi differential.

N, ex-teacher, "ex" is the operative thank the above.

 

[Thalassamania]

... The lungs do not "suck" air, the diaphram muscles increase and decrease the size of the lung cavity and atmospheric or ambient pressure simply fills the space with air. No, there is simply no way for numerous physical reasons presumably covered in Jr High science that a human cannot overcome even several psi differential.

N, ex-teacher, "ex" is the operative thank the above.

That's what "sucking" is, creating a negative pressure and then having air from a higher pressure area flow in.

 

[Nemrod]

Not to split hairs but let me try again, the diaphram muscles are not designed to "suck" air or to create a negative pressure, the muscle increases and decreases the size of the cavity allowing the lungs within that cavity to inflate and deflate effectively moving air in and out. The diaphram muscle not only cannot sustain but a very small negative pressure but would as well rapidly tire. The lungs don't suck anymore than a turbine engine, the atmosphere instead blows. The maximum atmospheric differential is 14.7 psi at sea level. Therefore there is a force at all times of 14.7 psi ready to fill the lung cavity when the diaphram muscle moves downward increasing the lung cavity volume. One might as well note that a regulator with much more than one inch cracking effort is very tiring to use, most people find about .5 inch comfortable.

Negative pressure is not possible. Absolute vacum is 0 psi. You cannot achieve 0 -14.7 psi or -100 psi. Maximum pressure differential from ambient at sealevel is 14.7 psi on this planet, on Jupiter it would be considerably higher and on Mars quite a bit less.

N

 

[vladimir]

Yeah, I know that they say you can embolize from shallow pool depths, but I've tried it from pool depths, and you would really have to have a deep breath held to embolize from six feet or less.

Is this a good idea?

 

[ACR]

The lungs don't suck anymore than a turbine engine, the atmosphere instead blows.

That's true, the universe doesn't suck... it blows

 

[Hank49]

The air pressure in the hose is 14.7 psi, assuming sea level. The pressure at four feet is atmospheric (14.7) plus the equivilent of four feet of water. Approximately 33 feet of seawater equals one atmosphere. At four feet the pressure your body sees is several psi greater than at the surface. The lungs do not "suck" air, the diaphram muscles increase and decrease the size of the lung cavity and atmospheric or ambient pressure simply fills the space with air. No, there is simply no way for numerous physical reasons presumably covered in Jr High science that a human cannot overcome even several psi differential.

N, ex-teacher, "ex" is the operative thank the above.

There's certain songs I can't play guitar to and sing at the same time.... and I am having a hard time getting the mentally clear image of exactly what happens here, which is bugging the s**t out of me because this should be pretty simple.
The only thing I can relate it to is trying to start a syphon. I do this a lot draining shrimp and fish tanks with 1 inch hoses. It's easy to do it at 1 foot head 2 feet a little resistance....3 feet gets a little stiff and 4 feet requires all I have in drawing power of my lungs to lift the water over the edge of the tank, which is basically the same resistance factor that my friend explained happened to him under water. This is caused by lifting the weight of the water when you start a syphon. So, we have this effect kind of but in reverse?
I just keep picturing air in a noncompressible tube...which would leave it at 1 atm even at depth. Your mouth is at the other end. but the air wants to compress as it leaves the tube and enters your mouth and lungs ?. Teacher? can I go to the bathroom now......?
Come on Uncle Thal.....I was counting on you to make this crystal clear...

 

[phunk]

I just keep picturing air in a noncompressible tube...which would leave it at 1 atm even at depth. Your mouth is at the other end. but the air wants to compress as it leaves the tube and enters your mouth and lungs ?

No, the air is at 14.7psi all the way from the surface, through the tube, and into your lungs. It's not the air pressure that changes, it's the pressure of the water squeezing your chest that gets higher. On the surface, you have the same pressure in your lungs as outside your chest. Underwater breathing through a tube, the pressure in your lungs is still the same as the surface, but the pressure outside has increased, the differential squeezes your lungs and makes it harder to inhale.

Scuba solves this by delivering air that's the same pressure as the water around you, eliminating the differential.

 

[ACR]

Take a ziplock bag, put a straw in it and fill it with air. (zip up the zipper around the straw)... notice that the air doesn't rush out. Now submerge the bag in a sink full of water, what happens? It gets pushed out right?

the bag = your lungs.

 

[Thalassamania]

ACR did it better than I could. Hope that clarifies.

 

[Jeannewg]

That YouTube thing is nuts.

I watched it the other day. I did some dumb stuff as a kid, but a scuba unit made from a pump sprayer?

I bet that kids winds up at MIT if he isn't dead first. =/

That kid is my son and is alive and well! He could only stay underwater for a few minutes, but it was worth the learning experience. Hopefully MIT will accept his YouTube video as an admission essay. He was so happy for the compliment! He has gone on to motorizing a bicycle and more adventures with his 3D printer he bought