BrainStuff Classics: Why Can't We Breathe Underwater?

Water is made up of hydrogen and oxygen, but in a form that we can't breathe. Learn more about how water works in this classic episode of BrainStuff.

Learn more about your ad-choices at https://www.iheartpodcastnetwork.com

See omnystudio.com/listener for privacy information.

Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff production of I Heart Radio. Hey
brain Stuff, I'm Lauren Vogelbaum, and today's episode is a
classic from our erstwhile host, Christian Sagar. The question of
the day, why can't we breathe underwater? Hey, everybody, it's
me Christian Sagar, and I am back with another brain

(00:22):
Stuff question, why can't we breathe underwater? I haven't met everybody,
but everyone that I have met has not been able
to breathe underwater, except for aquaman, of course. And it's
a good question when you think about it, because water
is made up of hydrogen and oxygen, right, well, it
goes in the chemicals. There's one thing we need to remember, though,

(00:42):
about those chemicals. It's that once they react in certain ways,
they form compounds that are often nothing like their original elements.
Think of two solo artists from different bands and then
they get together and they make an album that sounds
nothing like the original music. For example, if you react carbon,
hydrogen and oxygen together one way, you get glue close.

(01:05):
But if you react them together another way, you get vinegar.
And if you react them yet another way, you get fat.
And if you react them yet another way, you get
ethanol and glue close fat. Ethanol and vinegar are nothing
like each other, but they're all made from the same elements.
In the case of hydrogen and oxygen gas, if you

(01:27):
react them together one way, you get liquid water. And
the reason we can't breathe liquid water is because the
oxygen used to make the water is bound to two
hydrogen atoms, and we can't breathe that resulting liquid. The
oxygen that fish breathe is not the oxygen that's in
H two O. Instead, the fish are breathing O two

(01:50):
oxygen gas, and that's dissolved in that water. Many different
gases dissolve in liquids, and we can see an example
of this all the time with carbonated beverages. In knees beverages,
there's so much carbon dioxide gas dissolved in the water
that it rushes out in the form of bubbles. Fish

(02:10):
breathe that dissolved oxygen out of the water using their gills,
and it turns out that extracting the oxygen isn't that easy.
Air has something like twenty times more oxygen in it
than the same volume of water. Plus let's remember that
water is a lot heavier and thicker than air, so

(02:31):
it takes a lot more work to move it around.
The main reason that gills work for fish is the
fact that fish are cold blooded. This reduces their oxygen
demands tremendously. Warm Blooded animals like whales breathe air like
people do, because it would be hard to extract oxygen

(02:51):
using gills. Human beings can't breathe underwater because our lungs
don't have enough surface area to absorb orb enough oxygen
from water, and the lining of our lungs is adapted
to handle air instead of water. However, there have been
experiments with humans breathing other liquids like fluorocarbons. Fluorocarbons can

(03:15):
dissolve enough oxygen, and our lungs can draw that oxygen out.
It's just that first breath where you suck in the
fluorocarbons and they enter your lungs. That is not very pleasant,
but it is possible. And look, please, nobody out there
try to breathe underwater, because unless you're an extraordinary person

(03:37):
or maybe a mutant, you're probably going to drown. Today's
episode was written by Ben Bolin and produced by Tyler Clang.
For more on this and lots of other topics. Is
it how stuffworks dot com brain Stuff is production of
I heart Radio for more podcasts in my heart Radio.
Is it the heart radio app, Apple Podcasts, or wherever

(03:59):
you listen to your favorite shows. M