Speaker 1: Welcome to Brainstuff from how Stuff Works dot com where
Speaker 1: smart Happens. Hi Am Marshall Brain with today's question. If
Speaker 1: water is made up of hydrogen and oxygen, then why
Speaker 1: can't we breathe underwater? One thing about chemicals is that
Speaker 1: once they react in certain ways, they form compounds that
Speaker 1: are often nothing like the original elements. For example, if
Speaker 1: you react carbon, hydrogen and oxygen together one way, you
Speaker 1: get glucose. If you react them together another way, you
Speaker 1: get vinegar. If you react them together in another way,
Speaker 1: you get fat. If you react them in another way,
Speaker 1: you get ethanol. Glucose, Fat, ethanol, and vinegar are nothing
Speaker 1: like each other, but they are all made from the
Speaker 1: same elements. In the case of hydrogen and oxygen gas,
Speaker 1: if you react them together one way, you get liquid water.
Speaker 1: The reason we can't breathe liquid water is because the
Speaker 1: oxygen used to make the water is bound to two
Speaker 1: hydrogen atoms, and we cannot breathe the resulting liquid. The
Speaker 1: oxygen is useless to our lungs. In this form, the
Speaker 1: oxygen that fish breathe is not the oxygen in H
Speaker 1: two O. Instead, the fish are breathing O two oxygen
Speaker 1: gas that's dissolved in that water. Many different gases dissolve
Speaker 1: in liquids, and we can see an example all the
Speaker 1: time in carbonated beverages. In these beverages, there's so much
Speaker 1: carbon dioxide gas dissolved in the water that it rushes
Speaker 1: out in the form of bubbles. Fish breathe that dissolved
Speaker 1: oxygen out of the water using their gills. It turns
Speaker 1: out that extracting the oxygen is not that easy. Air
Speaker 1: has something like twenty times more oxygen in it than
Speaker 1: the same volume of water, plus water is a lot
Speaker 1: heavier and thicker than air, so it takes a lot
Speaker 1: more work to move it around. The main reason why
Speaker 1: gills work for fish is the fact that fish are
Speaker 1: cold blooded, which reduces their oxygen demands tremendously. Warm blooded
Speaker 1: animals like whales breathe air like people do because it
Speaker 1: would be hard to extract enough oxygen using gills. Humans
Speaker 1: can't breathe underwater because our lungs don't have enough surface
Speaker 1: area to absorb enough oxygen from water, and the lining
Speaker 1: of our lungs is adapted to handle air rather than water. However,
Speaker 1: there have been experiments with humans breathing other liquids like
Speaker 1: flora carbons. Flora carbons can dissolve enough oxygen, and our
Speaker 1: lungs can draw that oxygen out. It's just that that
Speaker 1: first breath where you suck in the flora carbons to
Speaker 1: your lungs is not very pleasant. Do you have any
Speaker 1: ideas or suggestions for this podcast? If so, please send
Speaker 1: me an email at podcast at how stuff works dot com.
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