Breath underwater with long hose or tube? Why would/wouldn't work?

Question

My dad says that the following idea wont work:

Simple (no springs) winding hose with one end always one foot above water- hose attached to inflated buoy. You bring one end, which only allows air to travel down, no water up, down into the water, and breath with it.

Will it? How far down? Why or what not? Are there any other easy ways to dive deep and breath for 10-ish minutes without holding your breath (home-brew; not scuba...)

Thanks!

(10 stars to best answer- garunteed)

Answer 1

Water pressure simply put...That's why a diving regulator delivers air at ambient pressure....For every 10 m./33 ft. you drop below you increase your pressure by 1 atmosphere + 1

ie. 10m. = 2 atms.....Your lungs just aint that strong no matter how bad you suck.

Answer 2

You won't get 3 feet with it. Your diaphragm ( the muscle that operates your lungs) isn't built to operate under much more than one atmosphere of pressure. Even at only a depth of three feet, you'd feel like you were tying to breathe through a very tiny straw. Scuba divers or divers on surface supplied air, get around this problem by having that air delivered at a slightly higher pressure than the pressure at the depth they're at. It wouldn't matter how wide your invention's tube is either. Your body simply can't do it. You need a compressor to make this work. One that delivers filtered air and a regulator to boot. Just like scuba or a hookah diver.

Answer 3

they tried it on mythbusters or braniac

(meh 2 spelling)

your lungs cant handle the pressure of sucking the air down the tube or sumthing

Answer 4

I don't disagree with the other answers that have been given so far, but I think some concepts could have been explained more clearly, so here's my (long-winded) attempt.

Breathing through a SHORT tube underwater can and does work (that's what snorkeling is all about), but if you tried to go deeper by simply adding an extension to your snorkel (or using a long hose as a replacement), you'd quickly realize three things:

1. Breathing through a long tube takes a lot of work:

This is because resistance develops when you try to move air inside a tube.  The longer the tube, the more resistance there is.  Similarly, the narrower the tube, the more resistance there is.  (Try finding straws of different lengths and diameters, and breathing through them for 5 minutes.  You'll see what I mean.)

2. If you breath out through the same tube as breathing in, you'll get winded very quickly:

On an average-sized breath, your lungs move about half a liter of air.  A standard snorkel (about 17" in length) contains about one-sixth of a liter of air in the tubing.  This means if you take in an average-sized breath through a snorkel, only two-third of what you breathed in is fresh (the other one-third is the "used up air" from the last time you breathed out).  

Now if you try to breath through a hose/tube that is 50" in length, and you only take an average-sized breath, ALL of the air you breath in will be "used up air" -- no fresh air!

Luckily, most people can take deeper breaths to compensate, but even when you take the deepest breath you can, your lung can only move about 4.6 liters (a little over one gallon) or air, so there is a limit to how long the tube can be.  Not to mention, trying to breath that deep for every breath is VERY tiring!

3. The deeper you go, the harder it gets to breath:

As another person mentioned, water pressure goes up very quickly as you go deeper.  You probably have felt the squeeze on your ear drums even when you tried to dive to the bottom of a swimming pool.

I don't know how far below the surface you want the home-brew device to take you, but even if you go just 16 ft below the surface, water pressure would have increased by about 50%.  

Water pressure will press on your chest, making it very hard (if not impossible) for you to take a breath in.  Scuba divers get around this problem by breathing compressed (high-pressure) air, which helps to push the chest out from inside the body.  Air through your long hose will be at the same pressure as on the surface, too weak to help push your chest out.

Water pressure will also press on your hose/tube and if your hose/tube is not strong enough, it'll get crushed by the water pressure as well!

=================

But if you really want to prove your dad wrong, then you need to:

1. Not breath in "used up air":

There is actually an easy way to beat this problem -- don't breath out into the hose/tube!  With some practice, you can breath in through the hose/tube in your mouth, and breath out through your nose (and let the "used up air" go up to the surface as bubbles).  If you can do this, every breath you take in will be fresh air -- but remember, you still have to deal with the resistance.

2. Make the hose/tube as fat as possible, and as rigid (strong) as possible:

A fat tube will reduce the resistance, and a rigid tube will help prevent it from collapsing from the water pressure.  (In fact, a 3-inch PVC pipe will be great from this regard, if only you could fit it in your mouth!)

Anyway, as you can imagine, a fat/rigid tube won't be very flexible, so your mobility will be severely limited underwater.

3. Unfortunately, there is no way to beat the water pressure problem, so you won't be able to go very deep.  But then again, maybe you just want to be able to clean the tiles at the bottom of a pool to prove a point, in which case, the water pressure will make breathing hard, but not impossible.

But if you are willing to go through all this, maybe taking a scuba course is not as big a deal as you think?  :-)

Answer 5

Your dad is basically right.  However if you significantly increase the diameter of the hose and attach it to a spherical shaped device or 'bell' (large enough to get your whole head into with 5-6 inches of clearance around and 1-3 inches above it might work without any other assistance.  The other option is to attach a bellows to the end of the hose (outside the water) and use it to force 'clean' air down and purge out the CO2 (again you would need a 'bell' to make this possible).  Either option is limited by the diameter of the hose in relation to depth and the effectiveness of the bellows.  I wouldn't bet on being able to get deeper than 15-20 feet.

Either way you do it you're asking for trouble.  Such 'home-brew' rigs operated without knowledge of diving, safety protocols etc pose a great risk of blackout and drowning among other (potentially less lethal) health risks).

If you want to dive, get scuba certified.  Its easy and relatively cheap.  Scuba diving would be safer and more fun than stuggleing with a make-shift rig that may or may not work.

Answer 6

If the tube is too long then you will just be breathing the same air you exhaled.  Depends on the capacity of your lungs and the capacity of the tube.