** Something I have known for years- water is unique and necessary!
Why Water Is Weird
What makes water unique among liquids?
One
day, frustrated after many hours of meditation and practice, Bruce Lee,
still a teenager, went sailing. His martial arts teacher, Yip Man, had
been instructing Lee in the art of detachment, a key facet of gung fu.
Lee couldn’t let go. “On the sea I thought of all my past training and
got mad at myself and punched the water!” he later wrote. “Right then—at
that moment—a thought suddenly struck me; was not this water the very
essence of gung fu? I struck it but it did not suffer hurt. I then tried
to grasp a handful of it but this proved impossible. This water, the
softest substance in the world, which could be contained in the smallest
jar, only seemed weak. In reality, it could penetrate the hardest
substance in the world. That was it! I wanted to be like the nature of
water.”
For Lee, the budding martial artist, water embodied an
ideal of lithe and effortless strength. He learned this from ancient
Chinese philosopher Lao Tzu’s Tao Te Ching and updated it,
adding, “When heated to the state of steam it is invisible but has
enough power to split the earth itself.” It’s striking that water can
illustrate and elucidate a martial arts philosophy while also being, to
this day, the “least understood material on Earth,” as researchers
reported recently.
Water can appear to be “fine-tuned” for life.
In their study
published in early 2018, Hajime Tanaka, John Russo, and Kenji
Akahane—all researchers in the Department of Fundamental Engineering at
the University of Tokyo, in Japan—tried to tease apart what makes water
unique among liquids. It’s got anomalous properties, like expanding when
cooled below 40 degrees Fahrenheit, which explains why lakes freeze
downward, from top to bottom, rather than up. Normally frozen solids are
more dense than their liquid equivalents, which would mean that frozen
chunks would fall to the bottom of a lake instead of staying on top.
Water also becomes less viscous compared to other liquids when
compressed, and has an uncanny level of surface tension, allowing beings
light enough, like insects, to walk or stand atop it. Since it’s these
distinctive features among others that power our climate and ecosystems,
water can appear to be “fine-tuned” for life.
The researchers, with the benefit of supercomputers,
were able to tweak and untune a computational model of water, making it
behave like other liquids. “With this procedure,” Russo said,
“we have found that what makes water behave anomalously is the presence
of a particular arrangement of the water’s molecules, such as the
tetrahedral arrangement, where a water molecule is hydrogen-bonded to
four molecules located on the vertices of a tetrahedron,” a shape of
four triangular planes. “Four of such tetrahedral arrangements can
organize themselves in such a way that they share a common water
molecule at the center without overlapping,” Russo said. As a result,
when water freezes, it creates an open structure, mostly empty space and
less dense than the disordered structure of liquid water, which is why
water props ice up. Both highly ordered and disordered tetrahedral
arrangements give water its “peculiar properties.” The paper’s title
spells this out: “Water-like anomalies as a function of tetrahedrality.”
Nautilus asked Richard Saykally,
a chemist at U.C. Berkeley, why these peculiarities make the liquid so
ripe for scams and fanciful speculations. The ancient Greeks thought
water was one of the four “essential” elements, the others being earth,
air, and fire. Homeopathy, which purports to cure illness using small
doses of disease-causing substances dissolved in water, evolved out of
this, Saykally said. But there are more modern magical claims about
so-called “structured” or “hexagonal” water. Some “wellness”
practitioners claim humans age in part because we don’t replenish our
stock of structured water. Depending on water’s structure, they say, it
can penetrate your cell walls more effectively and has all kinds of
health benefits.
“There’s no scientific basis to that at all,” Saykally
said. “You can’t make structured water. Doesn’t make any sense because
the hydrogen bond in water lives for a few picoseconds—10-12
seconds—and these hydrogen bond structures of water are rearranging very
rapidly so you don’t have water clusters existing as isolated entities
in water despite a lot of these claims.”
The ancient Greeks may have been wrong about water being
an essential element, but Saykally says it’s no coincidence that water
is essential for life on Earth. “It’s something intrinsic about water in
that the strong tetrahedral hydrogen bond network that water makes is a
very flexible environment for chemical processes to happen,” he said.
“It has the right properties to dissolve many ions; it has the right
properties to cause what we call hydrophobic materials”—like
proteins—“to fold up in special ways.”
Saykally has invented a new laser to study water
clusters, with the ultimate goal of producing “the perfect model for
water,” he said. “We want to combine all the information available from
studies of water clusters with our terahertz laser spectroscopy—from
quantum chemical calculations and from condensed phase measurements—and
make a computer model of water that will answer any question you ask.
That perfect water model is what we have been calling the universal
first principles model of water.”
You can enjoy the rest of our conversation with Saykally here, in which he says, among other things, whether another form of liquid water is possible.
Brian Gallagher is the editor of Facts So Romantic, the Nautilus blog. Follow him on Twitter @brianga11agher.
No comments:
Post a Comment