Life.
What is it?
What’s it’s purpose?
Was this an accident?
Where can we find more?
And why are we always looking for water?!
Water is essential for life.
We’ve all heard this, we all get thirsty, we need to drink water so it seems correct.
I mean everything else on earth needs water and biologists say that, so its probably true.
But why?
The universe is cold, water exists throughout mostly as a solid in the form of ice.
There are a lot of chemicals like ammonia and methane that exist in abundance as a liquid
throughout the galaxy, why can’t living beings use that?
Well simply put, they’re not water.
water is the most perfectly designed molecule, it is simplified perfection, the swiss army
chemical of the universe, its absolutely astounding what it accomplishes just by existing.
*intro*
Before life there was just chemistry.
Hydrogen fused within stars to create larger elements, stars exploded to spread those elements
throughout the cosmos, gravity brought those elements back together, and extreme heat,
radiation, and celestial collisions fused those together into even more complex compounds.
But in a dry universe that would be the end of the road.
There would be no life.
You see, Molecules are 3 dimensional objects and that means to form most new molecules,
two smaller ones must collide with the right orientation.
Without means for them to mingle and interact, this can never occur.
Thus, the most important function of liquids in our universe is providing a medium for
chemicals to move about and interact.
There are a lot of liquids that can facilitate this movement but most of these liquids only
exist in freezing temperatures, far colder than what life on earth could possibly exist
in.
Plus at these freezing temperatures, there’s very little energy around to break the bonds
in existing chemicals to allow them to reform into newer more complex species, they would
be completely dependant on radiation energy.
Therefore, Water’s ability to maintain liquid form at relatively high temperatures is what
makes it so special.
Lets figure out why, we’ll take these three neighboring elements and add the most common
element, hydrogen to them.
This produces ammonia, water, and hydrogen fluoride.
All three of these elements are strongly electronegative, a concept discussed in my previous video.
These differences in electronegativity with hydrogen mean electrons involved in these
bonds will prefer to be closer to the more electronegative element.
So in each one, ammonia, water, and hydrogen fluoride, there are more electrons closer
to these atoms than the hydrogens.
This creates an imbalance in charges called polarity where the hydrogen side of the molecule
has an electron deficiency thus giving it a slightly positive charge and the other side
of the molecule a slightly negative charge.
But not all of these compounds behave the same.
This polarity in all of these compounds creates a pseudo-ionic type bond between the slightly
positive charges in the hydrogens and the slightly negative charges in other more electronegative
atoms.
We call these types of bonds “Hydrogen bonds” and these hydrogen bonds are stronger with
stronger polarity.
So Hydrogen fluoride with its strongest polarity has the strongest hydrogen bonds and ammonia
with its lesser electronegativity has the weakest of hydrogen bonds between the three.
The stronger the intermolecular bond between molecules the more difficult it is to break
it and cause a transition of state into a gas.
So it makes sense that ammonia exists as a gas while water remains a liquid because water
has a stronger polarity and thus stronger intermolecular bonds.
But then why does water remain liquid even when hydrogen fluoride boils into a gas despite
its stronger polarity and hydrogen bonds?
This is where water becomes special.
You see, each hydrogen bonded to each molecule acts as its own personal slightly positive
charge.
And each orbital of unpaired electrons on the electronegative atom acts as it’s own
personal slightly negative charge.
This creates an imbalance in both ammonia and hydrogen fluoride.
As for every charge that bonds with the other, this produces three more of the other type,
so on average one molecule can only bond with two others.
Water however has two hydrogens AND two orbitals with unpaired electrons.
That means each water molecule can create 4 hydrogen bonds which produces a ridiculous
amount of stability.
Each water molecule can either form a double hydrogen bond with two water molecules, a
single hydrogen bond with 4 other molecules, or a combo of the two.
This can form a type of liquid lattice of water molecules which is what gives water
it’s amazing qualities.
So water is uniquely stable for what it is, which allows it to be a liquid when most other
similar compounds have already converted into a gas.
But why is it so essential to life?
As mentioned previously liquids are necessary for other chemicals to interact, transport,
and combine to form new and different compounds.
However, liquids aren’t the perfect mode of transportation as it relies that whatever
is being transported needs to be less dense than the liquid.
But again, water is special.
So the first component of waters swiss army toolset is that it’s an almost universal
solvent.
What does that mean?
Just like how ammonia, water, and hydrogen fluoride have polarity, or an unequal distribution
of charge, the majority of chemicals and compounds that exist have some sort of imbalance in
charges somewhere in their structure as well.
That is to say they have some type of polarity.
Because of water’s strong polarity, that means the charged parts of waters molecule
are attracted to the opposite charged portions of another molecule.
And like little kittens trying to get to some milk, they slowly nudge their way inbetween
the compounds.
Acting like a wedge, as the water slowly moves in between the molecules it increases their
distance from each other and thus reduces their intermolecular attraction, as this interaction
weakens it allows water to nudge itself further between the two molecules, further separating
themselves, further decreasing their intermolecular attraction, and eventually they become completely
detached. This polarity is probably the most important
characteristic of water
This means water can transport molecules and compounds far denser and heavier than water
itself.
The reason things sink and float is gravity.
If I place an object in water, the water underneath the object has more water molecules pushing
down on it than the water molecules at the top.
So this creates a pressure gradient that pushes the object up and if this force is greater
than the force of gravity, then the object floats.
But when something is dissolved in water it’s not just sitting in the water, it’s a part
a part of it.
So the force of gravity’s influence on the object or molecule affects the water around
it too, so it doesn’t sink.
This means water can transport just about anything just about anywhere.
This is essential for living creatures, as our cells need nitrogen, oxygen, phosphorous,
minerals, and a plethora of other important chemicals and compounds.
Now we can get these by consuming food, but how do we send those chemicals to all the
extremities and tissues in our body?
Of course the answer is water which can dissolve and transfer all of it throughout the body.
but wait, there’s more.
Water has a ridiculously high specific heat capacity, this is a term used to describe
a material's ability to store heat energy without actually heating up.
Because of waters 4 hydrogen bonds, there’s a lot more volume to store
heat energy and a lot more bonds that need to break before an actual molecule of water
breaks one of its bonds.
Because of hydrogen bonding, water has almost double the specific heat capacity of
the second best ambiently stable liquid.
This high heat capacity is really important for thermoregulation, not only for living
creatures but also for the earth.
Sudden changes in ambient temperatures take time to affect our bodies as it needs to cool
or warm up a lot of water mass.
Additionally Our oceans are also the principal storage for heat on earths surface and the
biggest buffer to slow down active global warming.
Since life began in water, its pretty important that the water remains water.
But over geological timescales the temperature on earth can get really cold, enough to freeze
most water near the poles and a decent reach towards the equator.
But unlike just about every other substance on earth, water becomes less dense when its
a solid.
This mean it’s solid form, ice, floats on top of its liquid form and acts as insulation.
If this was the opposite, then over the 10s of thousands of years of freezing temperatures,
the entire water mass of the poles would freeze solid and this loss in volume would have brought
in more water from near the equator which would have in turn frozen as well.
Leaving a lot less of a liquid environment behind and essentially causing the extinction
of anything living near the poles.
But due to hydrogen bonds and waters strange shape, Ice is actually less dense than water.
In its liquid form, waters hydrogen bonds are chaotic, forming and breaking constantly
and not every water molecule is bonded by 4 hydrogen bonds.
As as a result they can be a little smooshed together and have odd orientations and it’s
not that big of a deal.
But when we remove energy, or cool it down, that means it needs to increase it’s stability,
or in other words: as many water molecules need to form as many hydrogen bonds as possible.
There’s only one orientation where all water molecules can form all 4 hydrogen bonds, so
out of necessity, all the water molecules rearrange into this form to establish their
4 hydrogen bonds.
And because of this configuration, ice is actually less dense than water and thus it
floats.
It’s really weird and crazy that this happens.
So water exists as a liquid at temperatures where chemical and metabolic reactions can
occur, its the most polar stable liquid around making it a universal solvent.
It has an insanely high specific heat capacity and thus is a great thermoregulator, and its
solid state is less dense than its liquid state.
And all of this comes from a simple tiny 3 atom molecule.
The last thing to discuss is waters role in homeostasis and osmoregulation, or keeping
your body balanced and healthy.
Most of our body’s water is held within our cells and this liquid is necessary for
allowing the organelles and internal cell structures to move about and accomplish their
tasks.
These tasks, also called metabolism or cellular respiration both requires materials and produces
waste.
The cells ability to exchange one for the other greatly depends on the concentration
of solutes in the surrounding extracellular fluid.
The concentrations in these extracellular fluids are heavily dictated by water intake,
as more water dilutes the solutes and less water concentrates them.
A higher concentration not only means its harder for a cell to get rid of it’s waste
but this also means water will slowly escape from cells due to osmotic pressure which can
drastically shrink a cells size depending on the level of dehydration.
Eventually the water pulled from cells in the body will accumulate where it’s needed
most, the blood that carries oxygen and essentials everywhere else.
Along with the water also comes the waste which accumulates here often increasing the
viscosity of blood thus increasing the chances of blood clots and the strain on the heart.
Dehydration also causes stress on neurons that rely on a balanced concentration of electrolytes
in their surroundings to maintain their resting membrane potential.
All of this stress of course can be relieved by simply drinking, absorbing, and distributing
water back throughout our bodies.
So avoid unnecessary stress on your body and your life.
It’s tough enough as it is.
Keep yourself happy and healthy.
Remember to hydrate.