High Pressure

   This, my friends, is what high pressure should look like! No cloud good get off the ground under this kind of atmospheric pressure; hence our spectacular blue skies--so blue, in fact, that photographs of them look like squares of sky-blue paper unless you include something else in them (such as a crescent moon).
   As you may recall from my previous posting, Writer Under Pressure, I have been struggling with understanding the basics of atmospheric pressure. I pored over many a book to try to find the right metaphor, image, equation that would set off the "aha!" for the Accidental Naturalist. The problem with metaphors and similes, I found, is that they don't hold up under scrutiny. Atmospheric pressure is sort of like blue Jell-O, sort of like a bag of potato chips, sort of like balls bouncing on a pool table, sort of like an ocean of air. But not really and not if you want to add all sort of other necessary ingredients to your atmosphere--heat, wind, aerosols, moisture, clouds. Adding heat to blue Jell-O is not a pretty sight.
   Thinking that I needed to knuckle down and understand the physics of atmospheric pressure, I began reading about gravity, mass, weight, temperature, volume, Boyle's Law, Charle's Law, and the essential behavior of air molecules.
   In no time, I was confronted by "force per unit area,"  14.7 psi, hectopascals, V a P,  V a T, and the like. Eventually, I understood what all of this meant, but I certainly do not want to write a book about clouds using this kind of language. Nor would you want to read it. 
   Nobel-Prize Winning physicist Richard Feyman said "The glory of mathematics is that we do not have to say what we are talking about." The more I knuckle down, the more I believe the atmosphere works in such glorious ways that describing it is beyond words and mathematics equally. This last statement is the equivalent of a Hallmark card that starts out  "Words cannot begin to describe...."  and then goes on and on ad nauseum.
   This morning, I found two descriptions of the behavior of air molecules that worked for me. Neither metaphor nor equation, they are are simple descriptions that rely on well-chosen verbs and adjectives. And, most importantly, the authors write about air with a sense of awe and a light touch.
  John Suchoki writes this in Conceptual Chemistry: 
    "Think of the molecules of air inside the inflated tire of an automobile. Inside the tire, the molecules behave like zillions of tiny Ping-Pong balls, perpetually moving helter-skelter and banging against the inner walls. Their impacts on the inner surface of the tire produce a jittery force that appears to our coarse sense as a steady outward push. Averaging this pushing force of a unit of area provides the pressure of the enclosed air."
     Pure poetry! For me, this entire paragraph behaves like air molecules inside my enclosed brain: zillions, Ping-Pong, helter-skelter, banging, jittery. 

    In Meteorology Today, C. Donald Ahrens writes this:
      "Air molecules are in constant motion. On a mild spring day near the surface, an air molecule will collide about 10 billion times each second with other air molecules. It will also bump against objects around it--houses, trees, flowers, the ground, and even people. Each time an air molecule bounces against a person, it gives a tiny push. This small force (push) divided by the area on which it pushes is called pressure."
     And this:
    "Air molecules not only take up space (freely darting, twisting, spinning, and colliding with everything around them) but...these same molecules have weight. In fact, air is surprisingly heavy. The weight of all the air around the earth is a staggering 5600 trillion tons...The weight of the air molecules acts as a force upon the earth."
    Darting, twisting, spinning, colliding...I get it!
  And, in describing the differences in density of air molecules between the troposphere (the "bottom" 11 km of our atmosphere, the layer closest to earth) and the thermosphere (the "top" layer above 85 km), Ahrens writes:
    "The low density of the thermosphere also means that an air molecules will move an average distance...of over one kilometer before colliding with another molecule. A similar molecule at the earth's surface will move an average distance of less than one millionth of a centimeter before it collides with another molecule."

       Need a real-life visual? Here (above), from Conceptual Chemistry, is an illustration of the collision course one particularly delicious air molecule traveled. For the first whiff of this pie to reach this woman trying to read was circuitous, involving some 8 billion particle collisions per second.
     Now I am beginning to see and feel the invisible atmosphere. It is making my head spin. And, it is making me hungry.

Cumulus Gelatinous

Dessert created and photographed by M. Ruth

   Who, you are wondering, gets to devour this fabulously whimsical dessert tonight? Luckily, it's not you. And due to bad planning (or a stroke of luck), there are only two of these Jell-o-brand-instant-gelatin filled goblets instead of four. Not only did the Accidental Naturalist accidentally halve the Jell-o, but I doubled the whipping cream. So, it looks like I will be having cream clouds in my coffee all week.
    If you would like to re-create this dessert (boss coming to dinner?), I recommend actually following the recipe provided in my previous blog.
   Mmmmmmm.....

On the Lighter Side...

  The wonderful yet occasional Cloud Appreciation Society newsletter arrived in my inbox this morning. I am just one of 26900 CAS members from 85 different countries reading this fun-filled missive.
    I may be the only one making a very silly cloud-related dessert this weekend. Click here for a laugh, a groan, a recipe.

A Cloud is a Cloud is a Cloud...

    Because my recent foray into meteorology has revealed a black hole of understanding of chemistry—the structure of a water molecule (the building blocks of clouds), for instance—I have borrowed my son’s college text book on Conceptual Chemistry, a book he acquired from a textbook rental company called Chegg until August 1. It is June 22. I must hurry.

     I put the book on the small table next to the chair where I write in morning. I love the cover: a cloudless blue sky in the background, a snowy Yosemite National Park in the middle ground, and a sky-blue, computer-enhanced river in the foreground. In the water are the reflections of the snowy landscape and submerged models of water molecules—two small white balls attached to one red ball. I get it. Water as a solid, water as a liquid and…uh oh…where is the gaseous phase?

    I turn the book over and see that the entire back cover is dedicated to explaining the front-cover photograph. The gaseous phase is not shown, because, water vapor is invisible. (Remember, visible steam is not water vapor—it is liquid water, condensed water vapor). The back cover explains that when skies are clear, as in the Yosemite scene, the amount of water vapor in the atmosphere is relatively low. “This, in turn, makes it easier for the water molecules of snow to scatter directly into the gaseous phase. This process, called sublimation, explains why much of the fresh snow seen on dry sunny mountain peaks soon disappears without ever melting.”

     And then the best part of this book, the part that makes me know this book and I are going to be friends:  “These molecular perspectives enhance our ability to see beauty, rhyme, and reason in the world around is. This is the premise upon which this book you are now holding was written.”

     I love the fact that I am holding a book, an actual paper book of considerable weight (I am sorry about the trees, but am cutting back on paper consumption elsewhere in order to avoid e-books.) I love the fact that by holding this book—and also reading it—more beauty, rhyme, and reason will come into my life.

      I love the fact that a few years back, I was in Yosemite National Park in January to give a talk on marbled murrelets. My husband and I arrived at the park on a rare warm and sunny day. There was plenty of snow on the ground--just like in the photo above. It was stunning and perfect. The afternoon before my talk, we took a hike. I hadn’t walked on snow in a long time. It felt good. My head was down, watching my step, looking for the trail. It occurred to me that I was walking on former clouds. These were clouds in their packed down, solid, crunchy form. The waterfall across the valley was a former cloud, too. So was the river that has cut its way through the granite. As we hiked up the trail, my warm breath condensed with each exhalation. The visible vapor was a kind of cloud and I, therefore, was a cloud maker. As we followed the switchback up the mountain, I warmed up and started to sweat. My skin was moist. I had the potential to vaporize. All the liquid inside my body, my organs, my blood cells could vaporize. Then I remembered my skin had pores. I hoped they hadn't forgotten how to close. I really didn't want to be part of the water cycle--literally.

    This morning, I opened Conceptual Chemistry. Naturally, I do not start with Chapter 1, but Chapter 4, which is the chapter my son told me would be most helpful. It is about subatomic particles—electrons, protons, and neutrons—and how we understand these parts of the atom through conceptual, not physical, models. The two small white balls attached to the sides of one larger red ball is a conceptual model of a water molecule, the white balls representing hydrogen, and the red representing oxygen. We cannot create a physical model—a large-enough-to-be-visible replica of a water molecule—because we cannot actually see individual water molecules. Nor can we see the atoms of hydrogen or oxygen. Nor can we see the atoms’ electrons orbiting around a center of protons and neutrons the way planets orbit the sun.

   This planetary approach--the pretty darn good conceptual model I grew up with, has, according to the author of Conceptual Chemistry, become outdated. In new and more accurate conceptual models of the atom, electrons appear as…you guessed it…a cloud.