Water: Part II

I wish I could have thought of a clever title for this post. I thought some were cute, but they all got flushed.

Water is both essential to life and destructive at the same time.  What a paradox.  It's destructive in big tsunami like ways and in small, irritating, rusty ways.  Just the word "leak" can make some people shudder.  And why is that?  Why are there so many substances that do not react well to getting wet?

Electron cloud model of water atom

I started reading again on all the stuff I learned years ago about chemistry in order to bring some great enlightening insights to my readers on this subject.  When it comes to chemistry and physics, I think I would rather try to explain how quantum mechanics works.  I get excited talking about radio isotope decay and the significance of polonium haloes in granite, but water is far more difficult.  That's right.  The substance that should be the most familiar to us in at least two of it's forms is the hardest to explain.

This is because as much as people like to think that science can explain everything, the more you know about what science REALLY knows, the more you realize that they don't explain a lot.

Bohr model of the atom

Let's start with the fact that most atoms are invisible.  Yeah. Those cute illustrations of what scientists believe to be the working models of atoms are just illustrations.  Most people aren't even aware of this, because ever since grade school, we've been subjected to illustrations designed to teach us about the assumed properties of  atoms and even subatomic particles are presented with such assurance that this is "just the way it is."  And while the atomic models we are shown are the best models that can be developed based on the experimental behavior and empirical evidence, they are still just best guesses.

Our best scanning, tunneling, electron microscopes can only see the very largest of atoms, and the pictures are very fuzzy at that.  How many people outside the scientific community even understand that, below a certain size, you can't "see" molecular objects. That's right.  Once you get so far down in size, there is no actual optical resolution that works, because you can't focus wavelengths of light that would have to be so short that you can't create lenses to deal with them.  That's why the electron microscope had to be invented.  When you look at an image from an electron microscope, you are not actually seeing the object the way you would look at a bacterium under a standard optical microscope.  You are looking at an image produced electrically on a monitor that is interpreting the electrons that have been focused to bounce off the object you want to examine.  An analogy would be the image you get from a high quality radar array from many miles up in space looking down at a land mass on earth.

Physicists know that down to a certain point we can't observe what goes on at the atomic or subatomic level. How can we, when the very act of trying to see an object means bombarding it with electrons?  It would be like blind people trying to watch a basketball game by being on the court with the players and touching them and the ball in order to "see" what's happening.  So, always keep in mind that what we "know" about atoms and elements are based purely on observing how they react with other atoms and other molecules on a relatively huge scale compared to their actual size.  Most of what we know about electrons seem very well proven, otherwise we wouldn't have radio, TV, microwaves, etc.

We don't know with absolute certainty that the hydrogen atoms attach at an angle to the oxygen atom in that model you see at the top, but it's the best guess based on how we think water behaves relative to other molecules.  For instance, in the shapes and behaviors of proteins. But this does not explain why water has the extremely high dielectric strength that it does compared to other liquids.  Why is water such an extremely good solvent with so many other substances?  Why does water expand when it freezes, even when in higher density solution such as sea water?  We don't know why.  We only know that it does.  We can speculate that the electron orbital cloud of the hydrogen expands away from the larger oxygen atom, thus making it less dense compared to the surrounding liquid water molecules, but such a change in the spatial relationship would seem to indicate a higher, not lower energy state.  This is because, as some would suggest, the hydrogen bond state in water forms an "open lattice" structure and this open lattice gets bigger at the point of freezing.  Open lattice?  Suggesting that there is empty space between the atomic matter?  But nature abhors any kind of vacuum.  This is an odd mystery.

We don't fully understand how atoms attach to each other. Physics describes three types of bonding between atoms: hydrogen bonding, covalent bonding, and ionic bonding, but these descriptions are only due to observation of behavior at the macro level and based on theories about the electrical charges and numbers of electrons and protons that are in the atoms.  There is overlap in the characteristics.  Most of the bonds in the smallest molecules are covalent in nature, meaning that the atoms are sharing electrons to some degree.  Ionic bonding is more along the lines of purely electrical or "magnetic" type attraction between atoms.

Hydrogen bonding is not completely understood. As of this post, in the year 2011, there is still a call for scientists to come up with a definition for hydrogen bonding. (Note the line just before the contents box at the link.)  How is it that hydrogen bonding is described as being weaker than ionic bonding?  Sodium chloride crystals (table salt) are a simple paradigm of ionic bonding between chlorine gas and sodium metal.  But I can take a pint of pure (distilled or deionized) water and dissolve up to four or five tablespoons of salt in the water.  This demonstrates that the bonds of the crystals have been broken while the physical state of the water has remained unchanged.

The same weak hydrogen bonds that allow you to push your finger down on a plunger and "atomize" water from a spray bottle are the same strong hydrogen bonds that give nylon it's elastic strength.  The same hydrogen bonds that allow water to evaporate off your skin  are the same hydrogen bonds that connect amino acids across the spiral lattice of phosphates that make up the DNA helix, but that can easily be "unzipped" by ribosomes to create RNA or recreate new DNA molecules.  All of the soft tissues of your body are swimming in a sea of water.

The element of water behaves differently with so many other elements, and even behaves differently depending on the amount of the element present.  For example, you couldn't survive if you didn't eat enough salt in order to have sodium ions in your body.  Every nerve cell in your body depends on sodium ions carrying nerve impulses.  But what happens when pure sodium comes in contact with water in an unregulated environment?  Watch the video:



You couldn't do that safely with lithium or especially rubidium.  They are far more reactive than sodium.  If you'd like to see how stupid and spectacular some people can be with sodium, go to this link on YouTube.  The third video in the list is really an example of what not to do.

This is enough for today.  Go ponder what a miraculous substance water really is.  How anybody who understands the little bit we can comprehend about the world around us can be an atheist is beyond my ability to explain.  I will continue to repeat what I've said before.  People will believe what they want to believe no matter what the evidence suggests or proves.  Accepting this has kept me from going crazy when talking to people.

Shalom Y'all