Naked Science Forum
Non Life Sciences => Chemistry => Topic started by: bobdihi on 26/05/2018 07:24:10
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Fact is we can't live without water H2O. Lets assume we get enough oxygen from breathing air. So that leaves H2. Why can't we live without water? Can't we just consume or inhale H2 where water is not available?
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Why can't we live without water?
Water is the solvent that makes our bodies function:
- Water carries enzymes and acids/alkalis to our food to digest it, and nutrients are absorbed into the bloodstream dissolved in water
- Water carries nutrients, salts, proteins, hormones and blood cells in our bloodstream
- Inside our lungs, oxygen and carbon dioxide are dissolved in water on their way to and from the bloodstream
- Inside our cells, water carries salts, nutrients, proteins, RNA and all the cellular bodies
- Inside our cells, water provides the right environment for enzyme reactions to occur, allowing the cell to function
- Inside our nerves and muscles, water dissolves the ions that carry messages as electrical impulses
- Water carries waste products to our kidneys, where it is excreted as concentrated solution in water
Remove even 25% of the water, and the above processes are so impaired that you die.
Evolutionary biologists suggest that life on Earth started in salty water, and it now only continues because we carry that salty water around inside every one of our cells.
See: https://en.wikipedia.org/wiki/Body_water
Can't we just consume or inhale H2 where water is not available?
No.
Free hydrogen is not available to be inhaled by living creatures at sea level.
- If some hydrogen were released at sea level, it would immediately float up high in the atmosphere where we can't reach it (hydrogen is lighter than air - it lifted airships like the Hindenberg)
- Hydrogen is incredibly flammable. With our many modern electrical appliances, just turning on a light switch is likely to cause a massive explosion (like the Hindenberg)
- A mixture of Oxygen gas + Hydrogen gas does not have all of the chemical and electrical properties listed above that make our bodies work.
- Oxygen gas + Hydrogen gas does not make water, unless you trigger a chemical reaction with a spark (big explosion), or use complex catalysts to make a steady flow of electricity in a fuel cell (as used on some space missions). But the human body does not have these catalysts, and there is no point in having them as there is negligible hydrogen for us to use.
- Some bacteria living in oxygen-depleted mud at the bottom of swamps do use Hydrogen Ions as a source of energy. But Hydrogen Ions are not the same as Hydrogen Gas - and these bacteria have no oxygen to react it with anyway.
What happens if you put oxygen and hydrogen together (with a spark)? The Hindenberg was the predecessor to today's airliners (the dramatic part starts at 2 minutes 30 seconds):
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What would the Hindenburg have been venting as it made its landing approach?
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Why can't we live without water?
To a good approximation, we are water
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What would the Hindenburg have been venting as it made its landing approach?
At about 1:30, they talk about it dropping water ballast.
This would have helped them level the airship - there were paying passengers, and their comfort was paramount.
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Where is H2 in air? It is not stable.
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It's the solvent of life. Metabolic and homeostatic systems need something like water to function. It's polar and so good for holding and transporting ions and proteins, is of a balanced pH and so a good buffer, it's self-cohesive and so consistent and gradient, has high heat capacity and so a good thermoregulator, and is abundant on Earth in a liquid state and so easily accessed and constituted.
We would need a replacer to keep life in solution and stasis. Nothing would substitute that we can tolerate, let alone allow us to be such dynamic organisms. It would require great modification to our biochemistry, or we'd have to upload to a quantum computer, to survive anhydrous. It can be argued life evolved on the basis of H2O chemistry.
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It could be argued that we eat basically hydrocarbons, and breath in air, and breath out carbon dioxide. So, the body should be able to make water from food+air. Of course, food may also contain water.
Some animals, in fact, seem to be able to eat dry seeds and breath, of course.
http://www.bbc.com/earth/story/20160926-the-creatures-that-can-survive-without-water-for-years
http://education.seattlepi.com/types-adaptations-must-desert-animals-make-conserve-water-3567.html
Humans have evolved in areas where water was generally plentiful, and don't have the extreme adaptations necessary to conserve every drop of water.