Why Can't We Breathe Underwater??

It is a known fact that water is made up of oxygen and hydrogen, however, when we go underwater, why do we require an oxygen cylinder and why are we unable to breathe under water? In contrast, fishes can live only in water although they also breathe oxygen for their survival. Have you thought about this mystery?

Why can't we breathe underwater?

If hydrogen and oxygen gas come together, they form H2O. The reason we cannot breathe liquid water is because the oxygen that is used to make the water is bound to two hydrogen atoms, and we cannot breathe the resulting liquid. The oxygen is useless to our lungs in this form.

Fish "breathe" oxygen dissolved in water with the help of their gills. It turns out that extracting the oxygen is not very easy as air has approximately 20 times more oxygen in it than the same volume of water. Also, water is a lot heavier and thicker than air and hence it takes a lot more work to move it around. The main reason why gills work for fish is the fact that fishes are cold-blooded and this reduces their oxygen demands. Warm-blooded animals like whales breathe air just like we humans do as it is hard to extract enough oxygen using their gills.

Humans cannot breathe underwater because our lungs do not have enough surface area to absorb enough oxygen from water, and the lining in our lungs is adapted to handle air rather than water. However, there have been experiments with humans breathing other liquids like fluorocarbons. Fluorocarbons can dissolve enough oxygen and our lungs can draw the oxygen out.

The most important thing to understand here is how the same chemicals react in different ways with one another. For instance, if you combine carbon, hydrogen and oxygen together, one reaction can give you glucose, which is C6H12O6 and the same chemicals in another reaction can give you vinegar, which is C2H4O2.