Water is weird

Source: Wikimedia Commons. This file is licensed under the Creative Commons Attribution-Share Alike 4.0 International license.

What’s new?

Two researchers at the University of Southern California (USC) have shown that when a graphene electrode is placed into water the molecules of water closest to the electrode “align in a completely different way than the rest of the water molecules,” a result that was not anticipated. The findings may have implications in many fields, especially in methods proposed for desalinization of water.  

What does it mean?

Water has many strange properties, according to Alok Jha, author of The Water Book. Unlike most other liquids, water expands when it freezes; thus, ice floats in water, insulating life under the ice. Water in rocks expands in the cold and cracks the rocks open, an important fact in the creation of soil. Water, even though made from two gases, is a liquid. It has a surprisingly large surface tension, enabling insects to walk on it. The attraction between water molecules leads to capillary action, important to all life. Almost anything dissolves in water. I could go on and on since Rachel Brazil claims that water “has at least 66 properties that differ from most liquids – high surface tension, high heat capacity, high melting and boiling points and low compressibility.”

The electrode the researchers used is made from graphene, a very interesting form of carbon in which the carbon atoms are arranged in a single layer honeycomb lattice. It has promise to improve battery performance, hence its use as an electrode in this experiment.

The result they observed occurs at the surface of the electrode, where the water and electrode meet. Many interesting chemical and physical effects occur at surfaces. One of the researchers at USC concentrates on the molecular structure and physics of surfaces,” as explained at this web page about the Benderskii Research Group.

What does it mean for you?

I draw two lessons from these facts about water and from the newly reported research. First, science has increased our understanding of the world amazingly, but some simple parts of our world still defy our understanding; at least sometimes engineers can use the natural world in ways that science does not actually understand well. The fact that discoveries continue to be made about water – water! – amazes me.

Second, discoveries continue to be made that will improve our ability to generate, distribute, and use electrical energy. While not mentioned in the article, this result has implications for the development of batteries. I believe that we must move much more quickly than we are doing now to reduce the emissions of greenhouse gases to head off the climate changes that are occurring, but I also believe that surprises await us in science, engineering, and technology that will help us along this path. Stay tuned for more news.

Where can you learn more?

As you might expect, the US Geological Services (USGS) has a great page about the properties of water. This BBC animation, narrated by author Alok Jha, explores some of the strange properties of water. Some of those properties are listed here.

One thought on “Water is weird”

  1. Water is indeed weird–and wonderful.

    Water is also the key to understand global warming. But very few people know this, or understand the science behind it.

    The theory of global warming is that increasing levels of CO2 in the atmosphere, caused by burning fossil fuels, will trap solar heat, and thus raise tropospheric temperatures globally. Note that this is a THEORY (technically, it is a hypothesis, but let us be generous).

    CO2 certainly does trap solar heat. No one argues about that. In that sense, it is definitely a “greenhouse gas” albeit a very weak one. (And, of course, no one argues that CO2 levels are increasing, and that the source of the additional CO2 is combustion of fossil fuels. We know this from isotopic analysis.)

    But CO2 is a linear molecule, and C and O have roughly equal masses. Think of three masses connected by two linear springs. That’s how we model it. Now imagine that you compress the springs and let the molecule go. It will vibrate. As our molecule bumps into other molecules and surfaces, the vibrations will be excited. Note that the O atoms are kept away from each other. Because of quantum effects, the vibrational energies that this CO2 molecule can have are very limited. A passing photon must fall into one of several distinct energy bands for the molecule to absorb the light energy. And energy (hv) is proportional to frequency or inversely proportional to wavelength.

    Water molecules are quite different and much more interesting. The two H atoms have much less mass than the O, and in our model they are attached to O in a nonlinear fashion with torsional springs. Now we have all kinds of other vibrational modes to consider.

    The atmosphere has plenty of water vapor (0.2% to 4%), but very, very little CO2 (0.031% –and consider that this minuscule trace of CO2 is the source of carbon for all trees, wood, and foliage, all terrestrial animals, and our bodies; we are literally made from CO2.)

    Now let’s compare the absorption spectra of CO2 and H2O. [Sorry, I can’t seem to paste graphics.]
    Good example: https://i.stack.imgur.com/yIb3f.jpg

    Note how little energy CO2 absorbs compared to the complex absorption spectrum of water vapor. But there is one band of IR energy that CO2 can absorb: the band near 4×10^-6 wavelength. Practically all other IR energy from the sun is absorbed by the most powerful and predominant greenhouse gas, water vapor. (And there isn’t that much

    Getting back to global warming, the THEORY is that this tiny band of IR energy that CO2 can absorb–and that water vapor cannot absorb–is responsible for heating the globe very, very, very slightly. This tiny temperature increase is then theorized to increase the global humidity very slightly, and the additional water vapor will then absorb massive amounts of solar energy in all of its absorption bands. This will, of course, cause even more water to vaporize, thus raising the global temperature even more, leading to a catastrophic runaway greenhouse effect: positive feedback.

    That is the accepted theory of global warming. It’s not all about CO2; it’s really about runaway water vapor. (H2O is considered to be 1850x more powerful of a greenhouse gas than CO2.) It’s not even controversial–climate modelers and atmospheric physicists do not argue about it.

    In science, you cannot prove a theory; you can only disprove a theory. You come up with a theory, then you design experiments that refute your theory.

    Has the theory of global been disproved? Long-term satellite data shows that tropospheric water vapor has been decreasing for decades. See, for example, https://wattsupwiththat.com/2009/03/05/negative-feedback-in-climate-empirical-or-emotional/

    But there’s fascinating property of water to consider: water vapor does not merely absorb heat, it also transfers heat. As it rises in the atmosphere, it condenses, and gives up heat, transferring it to the upper atmosphere and to space, all the while blocking incoming solar energy (clouds). So you increase global CO2, and you increase the global humidity, but you also increase the earth’s ability to remove heat: negative feedback. Nature appears to have a self-correcting feedback mechanism.

    Which is right, the positive feedback system, or the negative?

    Up until very recently, climate models suggested the positive feedback mechanism, and gave us predictions of much higher global temperatures. That’s no surprise, because climate modelers did not even try to model clouds. Positive feedback was built into the models. (And these models were wildly successful at generating a positive-feedback research funding mechanism, too.) In addition, the “Pacific heat vent” (i.e. radiation of IR heat to space over the Pacific ocean) was not modeled, a known method by which earth loses heat.

    But recently, climate modelers started attempting to model clouds. It’s a very complex subject, and many parameters are not known, but it’s a start. Hopefully, we can get more accurate predictions from these new models.

    There is an alternative theory of global climate which has received little attention, but explains much more than the conventional theory, but it will have wait for another day. I’m too exhausted to write about it tonight.

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