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is it possible? Breathing underwater without a tank... Answered

Hi all,

Could it be possible to make a device that lets you breath underwater like the fishes do?
Think about something in the lines of a wearable filter off some sort that scrubs Oxigen from water molecules...
So, if that would be possible, how would one make such a device???

Just wondering.


I remember reading about a membrane years ago that would allow oxygen to pass through. But it required quite a large surface area to get enough oxygen for a person to breath, it might be suitable for an underwater dwelling. I don't know if anyone has improved on that.

In a different vein, yet another nanoscale device no one has come close to making is the respirocyte, a little machine you would inject into your blood stream in the zillions, when oxygen levels were normal it would store oxygen and when they dropped a bit, they would release it.

They are called Rebreathers and cost several thousand $$.

While they don't act like a fish's gills to pull O2 from the water. They do recycle gases giving divers a much lighter pack and in some cases more diving time.

If we could create a device that pulls O2 from the water it probably wouldn't be able to do it fast enough to give use breathable air. It would probably have to be connected to like a Heart and Lunge bypass machine so it could transfer the oxygen directly into our blood stream. Not a very fun way to go diving.

Come to think of it we have devices like that already. Problem is they are the size of an 18 wheeler. They are used on nuclear subs. They use high voltage to break the water down to its base elements. The system stores the oxygen and dumps the hydrogen overboard. Wouldn't be able to get it down to the size of a backpack cause you need a good power source, a way to filter the water, storage tank for the oxygen and many pumps and control valves to make it all feasible. You would have to have a full tank of oxygen before you started your dive since the system wouldn't be able to keep up with how much you are using. Which is why i mention connecting the system directly to your circulatory system. Its a more efficient way of giving you the oxygen you need. But you don't want your lungs to stop working.

So what your saying...

If i tie myself to a nucliar sub with ropes, put a couple of tubes into my bloodstream, and my lungs for extra measure... i would be able to breath underwater for an infinite amount of time.

Altough painfull and potentially lethal in soooo many ways... it would be possible?

How do these scrubbers work, and would it have to be so huge?
If i look at fish and watch there gills, the size of there gill is so much smaller in comparison to our lungs and body mass... how come it works for them?
Do they use less oxigen tham mammels?
Or do there gills work so good its inconcievable for us humans to copy it yet with our current technological level of understanding nature?

It would be very dificult to make artificial gills. Also, you would need to pump your own blood through the gills to make it work, or as kiteman said, make artificial blood that you can replace yours with (bad idea!). If we really needed to, I imagine science COULD make it, but they's probably acciddentally kill many people while developing it.

You would need artificial gills with an equivalent (or greater) surface area than the lining of your lungs.

You would need to circulate within those gills a liquid capable of absorbing oxygen from the water, yet giving it up on demand - artificial blood, if you will.

You would need to circulate the fluid, and power the pumps, all within a self-contained unit.

At an absolute minimum, the device would probably be larger and heavier than you.

Far easier to stick with scuba gear.

from the all mighty wikipedia (for scale comparisons)

The human lungs are the organs of respiration in humans. Humans have two lungs. Together, the lungs contain approximately 2,400 kilometres (1,500 mi) of airways and 300 to 500 million alveoli, having a total surface area of about 70 square metres (750 sq ft) (8,4 x 8,4 m) in adults — roughly the same area as one side of a tennis court.[1] Furthermore, if all of the capillaries that surround the alveoli were unwound and laid end to end, they would extend for about 992 kilometres (616 mi). Each lung weighs 1.1 kilograms (2.4 lb), therefore making the entire organ about 2.3 kilograms (5.1 lb).

Hehe, most of my pupils end up knowing that, if you opened up your lungs to make a flat sheet, it would (a) cover a tennis court, and (b) hurt a lot.

Hopefully your students don't use Wikipedia's "therefore" math...

1.1 kg X 2 = 2.3 kg ???

I'd assume they're just quoting to one decimal point, rather than rounding.

According to Jethro Tull there is Aqualung :-)

Sooo..... it could be made? Human fishy lungs that is...

for various values of "could". anything (in theory) COULD be made....given the proper criteria.

You might be able to generate enough to sustain you, just not for very long before the battery runs out. If you ran line voltage from the surface, it would be rediculously dangerous, but you might get enough oxygen.

I'm thinking electrolysis might work. It involves using a lot of electricity to pull hydrogen and oxygen out of water. The problem is that it would require really high current electricity at a pretty high voltage (at least 12V or 20V) go get enough oxygen to breathe. Not to mention, the hydrogen and the fact that the leads in the water would corrode, AND salt buildup would probably remove conductivity.

Liquid breathing with perchlorethylene fluid has been done experimentally in human volunteers undergoing lung lavage procedures apparently, but breathing liquids in humans is very difficult, and it was extremely hard to get the flow through needed for oxygentation at anything but rest.


There have also been interesting experiments with rats, and I recall a *very* early preemie that was treated some time back in a similar method, but I've not been able to find the article again...

In the US edit of "The Abyss" its actually demonstrated on rats - not special effects, genuine fluid (and rats...) , in the UK version it was censored in later edits.