Ordered structures left alone will eventually become disordered. This gain of entropy is a fundamental feature of thermodynamics. It’s kind of like your room: it can be messy in countless ways, while only few arrangements seem neat and tidy.
On an otherwise uneventful flight from Seattle to Frankfurt, I immersed myself in something memorable: a book written by the distinguished chemist Giorgio Piccardi (Fig. 7.2). A colleague had recommended this classic, but for the life of me, I could not imagine how a book entitled The Chemical Basis of Medical Climatology2 could possibly bear on the subject of water and energy. Once I began reading, however, even a sputtering airplane engine could not have drawn me away.
luminol for light amplification. He then sealed the containers
Equation 2 emphasizes that water and energy go hand-in-hand. Purists may decry the mismatch of units, for which I have no defense.
The reason for water’s high heat capacity has been a matter of debate — but please refer back to Figure 7.13. Radiant energy certainly raises water’s temperature, but some of that radiant energy is drawn off to build structure. That is, only some of the input energy goes toward heating. As a result, water needs to absorb a larger than expected amount of radiant energy in order to raise its temperature by some amount.
Salt and sugar crystals represent extremes of the like-likes-like mechanism. To produce sugar crystals, you dissolve sugar (sucrose) in water and heat the solution in the presence of an immersed seed crystal. As the water slowly cools and evaporates, a crystal forms. This “hard” crystal is known as rock candy. Its many opposing charges keep it solid. The presence of those charges can be confirmed by cracking the crystal in the dark (see figure). As the crystal breaks, the separated charges jump across the fracture, producing a discharge similar to lightning.
The schooling behavior of fish usually gets explained in evolutionary terms. However, a slimy, gel-like substance coats the fish surface. Gel-like substances create exclusion zones, with protons lying beyond. Could fish capitalize on the like-likes-like mechanism to help organize more efficiently?
Sandcastles. Standing to protect us against the specter of invading flotillas, sturdy sandcastles (Chapter 1) may achieve their strength by the like-likes-like mechanism. Those castles are not built from sand alone; they also contain water, which enables the building of EZs around each sand particle (Fig. 8.14). Thus, protonated water molecules lie between the EZ-enveloped sand particles. Those unlikes constitute the glue that holds together the castle.
Bacteria do much the same (Fig. 9.11). They move toward near-infrared light in the same way that the microspheres above moved toward the restricted light beam. The bacterial movement is hypothesized to arise from an infrared sensor lodged inside the cell.10 While that might be the case, the movement toward light so closely resembles that of the microspheres that one may rightly ask whether the physical mechanism under consideration might be at play.
Thus, we can appreciate why “infrared” and “heating” often come in practically the same breath when dealing with water. Water absorbs infrared; it therefore “heats up.” Water also emits infrared, and therefore it “feels warm.” We need to bear in mind, however, that “infrared” and “heating” are not interchangeable.
When your hand encircles a container of water, it absorbs the radiant energy that the water emits (through the container). If the water emits a lot of IR, you interpret this as warmth; if there’s not much IR generated, then you sense coolness. Your hand senses the radiation emitted, relays it to your brain, and presto! — you know if it’s hot
Discrepancies between observation and theory often lead to the introduction of such expedients as “sub-diffusion” or “super-diffusion.” Proteins, for example, are said to exhibit sub-diffusion,2 whereas particles in meteor trails are said to exhibit super-diffusion.3 These terms merely emphasize that standard diffusion theory does not work as consistently as one might hope.
Thus, membranes are unnecessary — the membrane is merely a convenient artifice for separating positive hydronium ions and negative charge. Membrane or no membrane, the central protagonist of osmosis is the hydronium ion, created by the absorption of external energy. Hydronium ions always move toward negative charge.
The task is formidable: according to standard plant biology sources,2 breaking a walnut shell requires a pressure of 600 pounds per square inch — approximately the pressure exerted by three husky men resting their collective weight on a postage stamp.
Over its lifetime, a modern AA alkaline battery can deliver as much as 1 mA of current for 1,400 hours. The product of current and time yields 5,000 coulombs; that is, an AA battery can deliver 5,000 coulombs of charge. A typical lightning bolt discharges 15 coulombs. Thus, the diminutive AA battery contains enough internal energy, in theory, to drive more than 300 lightning bolts.
In order to make bubble patterns visually enticing, champagne manufacturers purposefully etch patterned defects onto the insides of their glasses.
The most direct strategy for probing the insides of vesicles is simple: collect their contents to see whether the gathered molecules contain protons. We followed this strategy using the expedient of boiling. When water boils, bubbles break at the surface and their contents get expelled as vapor. We collected that vapor, condensed it into liquid, and measured the liquid’s pH. The pH progressively diminished with boiling time.
Fracturing probably results from excessive tension. To understand how this might happen, consider the equation governing tension on a thin membrane. For spherical membranes with thin walls, tension is given by the Laplace relation, T = Pr/2, where T is the membrane tension, P is the pressure difference across the membrane, and r is the radius. When a curved plane flattens, the radius of curvature, r, approaches infinity. The numerator of the equation can then become extremely large. Even a minor pressure difference across the membrane, P, will create enormous membrane tension. That small pressure differential might arise if, say, one of the two adjoining vesicles received slightly more radiant energy than its counterpart. Any such minor pressure difference can create huge tension. Then ... zap! The boundary fractures.
Fusion, as you will see, is what makes boiling possible. If you watch carefully as you turn up the heat beneath a pot of water, you’ll witness the succession of growth stages that eventually lead to boiling:
First you may see occasional small vesicles, which seem to mysteriously vanish; presumably, they pop inside the water.
From this analysis, it would appear that the critical variable in the equation of boiling is not temperature; more fundamental is vesicle concentration. It may just happen that vesicle concentration commonly reaches threshold at temperatures close to, although not necessarily precisely1 at 100 °C.
Curious about the possibility of reaching very high temperatures without boiling, my student Zheng Li took a smooth, asperity-free glass beaker and filled it with laboratory-grade, distilled, deionized water. EZ nucleation sites should have been rare or absent. He then applied heat. Even when the water was heated to well above the usual boiling temperature, no boiling was evident — until he threw in some dirt. Introducing those nucleation sites brought instant boiling. He got the same result when he inserted a stirring rod — instant boiling.
Once the vesicles stop popping, the clatter will subside. That happens when vesicles begin fusing rapidly enough to transition into bubbles. The bubbles produce a quieter sound as they break through the surface and open into the air. Each bubble-breakage event contributes to that gurgling sound.
There’s more. If you look at Figure 15.1, you will notice that the vapor does not rise uniformly; a series of “puffs” ascend, one after another. The surface seems to emit vapor puffs one at a time. Each puff comprises numerous vesicles, and each vesicle comprises huge numbers of water molecules. Hence, astronomical numbers of water molecules rise with each belch.
We soon noticed that the tubes rose only from limited regions of the surface. One region might emit a cloud or unleash a strand, while regions immediately adjacent might produce nothing at all — no detectable evaporation. The discharging zones might shift over time, but, at any given point in time, a cloud would emerge only from limited regions of the surface.
Those evaporated vesicles, often called aerosol droplets, may eventually condense to form clouds. The water contained in those clouds can be massively heavy: an atmospheric science colleague estimates the weight of clouds not in terms of kilograms but in terms of easier to fathom units: elephants. In a large cumulonimbus cloud, the total aerosol droplet weight can amount to fifteen million elephants.
A familiar example of this electrostatic lifting force may be seen in waterfalls. Descending water creates a mist of droplets that rise upward, forming clouds. Such clouds can rise above the tops of the falls (Fig. 15.14). Since droplets cannot mechanically rebound higher than the height from which they started, some other force is implied,
My primitive crystal radio performed almost as impressively; it too could pick up radio signals sent from huge distances. Yet, it had no battery. Those far-traveling signals must have contained the necessary energy — energy enough even to power my headphones.