It is said that Blaise Pascal wrote in a letter of 1657 a line to the effect, “If I had more time, I would have written a shorter letter.” Don Lemons has taken the time to write a short book that says much in a few well-chosen words. Drawing Physics is a concise set of 51 essays, with each focusing on a particular point of physics where reasoning centers around a simple, clear drawing. The essays are organized into five eras: “Antiquity” (essays 1–9), “Middle Ages” (essays 10–13), “Early Modern Period” (essays 14–31), “19th Century” (essays 32–39), and “20th Century and Beyond” (essays 38–51).
I envision two audiences for Drawing Physics: (1) laypersons who want to know, at the conceptual level of a well-presented public lecture, crucial points of physics and how physicists came to know them; and (2) teachers of physics and their students at the high-school, university, and graduate levels. Both audiences are well served because the essays, while short, are packed with colorful descriptions, anecdotes, and contextual background all working together to offer snapshots of the personalities involved while describing the evidence-based reasoning they used. The essays provide sparkling settings for stories behind the laws and theorems that fill textbooks, turning physics icons into real human beings. Professor Lemons manages, in few words, to integrate physics with historical context, philosophical overtones, and the culture of the subject's time and place, enhancing an appreciation of physics as craftsmanship while telling the stories that are behind the stones in the cathedral of knowledge.
Let me indulge in one example of Lemons' remedy to the kind of detail often missing from traditional accounts. Consider how doubts about the caloric fluid hypothesis arose with Benjamin Thompson's (also known as Count Rumford's) cannon-boring enterprise. The 2004 edition of Randall Knight's excellent introductory text, for instance, tells us that “Thompson fled to Europe during the American Revolution, settling in Bavaria and later receiving the title of Count Rumford.”1 Of course, such introductory texts are already obliged to include more content than can be realistically covered in two semesters, leaving precious little room for interesting back-stories. But in a few lines, Professor Lemons manages to give us a richer picture of the Count, bringing him to life as a character of intrigue:
“Benjamin Thompson's cannon boring experiment of 1789 had seriously undermined, without altogether discrediting, the concept of a conserved caloric. Thompson (1753–1814), later known as Count Rumford, was an American original, sharp but self-aggrandizing. Born in Woburn, Massachusetts, his sympathies shifted to the British during the Revolutionary War, and when the tide turned in favor of the new nation Thompson left the rich widow he had married and resettled in England. Within a few years, King George III had knighted Thompson, and, with the king's blessing, he became a scientific and military advisor to the elector of Bavaria all the while continuing to spy for his British patron.”
Lemons goes on to describe Rumford's cannon-boring observations that threw doubt on the caloric model and prepared the way for James Joule and the mechanical equivalent of heat. But one cannot teach the demise of the caloric theory quite the same ever again; along with the story of caloric comes international intrigue. Upon sharing his story, Benjamin Thompson/Count Rumford goes from a distant name to a personality. We know not only what he did, but we also find out a bit about who he was. Physics appreciation is deeply enhanced with responsible story-telling.
Drawing Physics offers another quality absent from stick-to-the-core-facts approaches. Excellence in science, like excellence in painting or poetry, requires not only mastery of the tools of the trade and creative play of the imagination but also insightful ways of seeing. Professor Lemons writes in his preface, “Drawings that jump-start a physical inquiry and encapsulate its results require neither rich detail nor realistic perspective—only simplicity and clarity. A good physics drawing is in many ways like a good epigram: spare and, once composed, its elements cannot be subtracted from, added to, or rearranged without diminishing the composition…” In Lemons' stories and drawings, we see fifty-one instances of creative minds. That quality, told through the background stories, deserves to be as essential a part of physics pedagogy as inquiry-based laboratories because both background stories coupled with hands-on engagement draw us into the creative act while remaking the discovery for ourselves.
Since 51 essays and their drawings cannot cover all important points of physics, it would be easy to criticize the omission of this or that topic. If one were so inclined, one could, for instance, complain of there being no essay about, say, Avogadro's constant, or the transistor, or the accelerating universe. But Lemons set for himself tight criteria for selecting the necessarily limited number of topics to include in Drawing Physics. In his Afterword, he explains that “the principles with which I have selected concepts to explore in these essays are those that can be drawn and seen…” (original emphasis). Perhaps the day will come, he suggests, when our vocabulary of concepts will be sufficiently enlarged that today's esoteric abstractions will be tomorrow's clean drawings.
Some common historical misconceptions are clarified. For instance, in essay 32, Lemons demonstrates how Young's double-slit experiment—as Thomas Young allegedly did it—relied on analogies to water waves; the quantitative analysis came later from Augustin Fresnel. In essay 38, Lemons makes clear the distinction between Planck's 1900 quantization of the mechanical energy of a simple harmonic oscillator and Einstein's 1905 hypothesis that light itself is quantized. However, this book contains (as all new books do) a few minor sticking points that could perhaps be addressed someday in a second edition. For example, in essay 44, the distinction between Einstein's interpretation of the photoelectric effect as an application rather than the motivation for the light quantum concept could be sharpened, as could a distinction in the Hubble expansion essay (number 46) between familiar Doppler redshifts and redshifts that come from the stretching of space. But I will not be overly pedantic. Drawing Physics offers an excellent summary of vast amounts of physics, told through intimate glimpses of physics history, whose writing required sifting through boatloads of historical research. Citations listed by the page number for facts and quotes that appear in each essay are found in an appendix, which is followed by an extensive bibliography.
Garrison Keillor, who for many years emceed the National Public Radio program A Prairie Home Companion with its centerpiece “News from Lake Wobegon,” was a masterful story-teller. Keillor knew just how much and what kind of detail to include, within the constraints of limited time, to bring his characters and their doings to vivid life. The listener sitting by a radio could see it. In Drawing Physics, Don Lemons has achieved something similar in telling the stories that lie behind so much physics. The next time you are preparing to present Archimedes' principle or Kepler's laws or the Carnot's theorem to your class, read the corresponding essay in Drawing Physics prior to your presentation. You will find yourself sharing with your students documented stories of the oh-so-human people behind the principles and laws and theorems that carry their names. The physics content will spring to richer life, reducing the distance between textbook icons and we who aspire to be their intellectual companions.
References
Dwight Neuenschwander is a professor of physics at Southern Nazarene University, Bethany, OK, the former manager of the AIP Education Division and SPS director, former editor of the Society of Physics Students/Sigma Pi Sigma publications and of the Forum on History of Physics newsletter; and the author of three books and the “Elegant Connections in Physics” column of SPS for 20 years. His latest book (2017) is the updated and revised edition of Emmy Noether's Wonderful Theorem.
