What are the fundamentals of the Laws of Nature? It’s challenging to find a book that threads the needle between being too simple and being too difficult, that gets at the big picture without sacrificing the important details. I’ve just stumbled on a delightful book written two decades ago by Michael Munowitz: Knowing.
It’s an ambitious book. I’m five chapters in, and I think Munowitz rises to the challenge. Here’s an excerpt from his short opening chapter, aptly titled Great Expectations: “Look closely at the weave of the world and see, as if in a tapestry, a frugal simplicity masquerading as complexity. Go beyond the finished work, which can only dazzle, to find the pattern hidden within. Take apart the tapestry strand by strand, color by color, stitch by stitch. Find the regularity. Find the rules. There must be rules. Nothing can be as complex as the universe first appears, and nothing deceives the mind more than complexity.”
Munowitz is an engaging writer. I daresay he has the gift of communicating the seemingly alien concepts of the physical sciences in a language anyone can understand. But it does require some effort from the reader to read slowly, pause, and think. While the prose is fluid and seems effortless, don’t be fooled. There’s a lot of hard science packed into it, and by taking the time to chew over what he conveys, I think the reader will come away with a much better foundation of how Nature works. And where does it all begin? By observing, measuring, and then looking for patterns!
I particularly liked that Munowitz chose the interaction between two particles to begin his quest for the explanation of everything. Chapter Two is aptly titled Ties That Bind. And in a subheading titled “The Potential To Be Different”, Munowitz introduces us to Jack and Jill going down the hill. Far away from each other, their walking path seems random. But as they get closer and start to notice each other, they draw nearer. “Closer and closer they come, and with each step the sense of attraction increases. The symbolic slope grows steeper.” At some point, they will get too close for comfort, move away from each other, and settle into a comfortable (equilibrium) distance. Here’s a picture from the book.
The Bond-Energy Curve is the fundamental underlying business of chemistry. I feel that using it to scaffold all of chemical bonding is conceptually helpful to students, and so I lead with it in G-Chem. We go through several examples to illustrate how different interacting particles prefer different equilibrium distances and have “energy wells” that may be deep or shallow. I try and hammer home the key principle that breaking a bond requires energy input into the chemical system, while forming a bond (which lowers the energy of the system) release energy to the surroundings because of conservation of energy. This is challenging for students, because in most chemical reactions, both bond breaking and bond forming are taking place simultaneously! Thus the net energy change of the chemical system may be positive or negative depending on the relative strength of the chemical bonds in the reactants versus the products.
In Chapter Five (Mass as a Medium), Munowitz tackles the equivalence of mass and energy. It’s mostly about E = mc2 (multiplied by gamma as things pick up speed) and the warping of space time, but I like how he introduces potential energy wells. Imagine two hills of similar height with a valley in between. A ball starting at rest on top of one hill gets nudged, and rolls into the valley. It picks up speed as it rolls down (potential energy being converted to kinetic energy), and after reaching the bottom starts to go up the other hill (kinetic energy being converted back to potential energy). Will it make it to the top? Or get trapped in the valley? If the ball loses some energy, then it will get trapped. How might this happen?
Here's Munowitz: “Suppose that the particle does not keep every bit of energy the field bestows. It has a mass, remember, a built-in store of energy, an endowment that depends neither on its own motion nor on the influence of any external agent. And by giving away some of that internal energy now, by losing mass, the particle avoids climbing all the way up to the top. It settles in the valley, finding a new stability with less mass and less rest energy than before. Somebody else pockets the difference.”
In G-Chem, we discuss this in the chapter on Nuclear Chemistry when we go over the source of energy in fission and fusion nuclear reactions. The missing mass is small, but it translates into a wallop of energy, thanks to E = mc2. I tell my students that this chapter is different from any of the chemistry we discuss all semester long, where the making and breaking of chemical bonds involves rearrangements of electrons (with no change to the atomic nuclei). Yet the same thing happens when a chemical bond forms. The two atoms that form a bond get trapped in an energy well. A tiny amount of mass goes missing, much tinier than in nuclear reactions. I’ve mentioned this in my class, but I don’t think the students really get it. Jack and Jill, when they get together, shed some hair or dead skin as they approach each other going downhill.
I’m looking forward to slowly working my way through the rest of Knowing. I hope that Munowitz tackles complexity in some satisfactory way even though the opening chapter hints of an essential reductionist approach, which I think ultimately fails if not paired with thinking about emergence. Analysis and Synthesis. We need both bottom-up and top-down to complete the picture. Munowitz hints at a broader approach in Chapter Four where he introduces three regimes of nature:
1. A clockwork mechanism: “Every move would be predetermined by the one that came before… With enough observation, with enough analysis, with enough familiarity, we might eventually learn what makes everything tick.”
2. The quantum realm: “For small particles confined in small spaces, the universe submits to a different kind of government… under which the promise of omniscience is honored (after a fashion) but devalued at the same time… It is a knowledge not of certainty, but rather of probability and chance.”
3. Chaos: “Between certainty and uncertainty, there is a third form of governance… where the promise of mechanics is upheld according to the letter of the law yet mocked in spirit. We find it everywhere… in the ordinary occurrences of every day life, often the richest and most complex to be found.”
This third regime is the cutting edge of science in my opinion. There is so much more to learn and know!
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