Why Don’t Spinning Tops Fall?

DeLisi presents a science primer in the form of talks between a mother, a father, and their very curious teenage child.

The author, a biomedical scientist and dean emeritus of the Boston University College of Engineering, offers a young central character, Caroline Angstrom, as a stand-in for readers of all ages, who may not realize that they probably have basic questions about how things work in the world: “The mysteries surrounding us become so embedded in daily life that they no longer register as mysteries,” he writes in an introduction, “until someone asks a question.” In these pages, Caroline, from age 13 to 17, offers queries on such topics as air pressure, acoustics, the nature of light, how aeronautics works, the nature of electricity, and how to understand climate science. She’s full of questions, and her parents—Mar, who works on Wall Street, and Don, a famous pianist—have plenty of answers; in each chapter, the pair explain the latest object of Caroline’s curiosity, not as a science lecture, but as a conversation. (The explanations are supported with ample notes, citations, and links.) DeLisi also interjects his own narration to clarify Caroline’s thought processes along the way: “The explanation of why bone is less transparent to X-rays than soft tissue led her to the more general question of why certain substances are transparent while others aren’t,” reads one such passage. “She wondered, for example, why visible light cannot pass through wood.”

Such a conversational approach to technical explanation is hardly new, but that’s because it works, and DeLisi executes it smoothly and with clear confidence. That said, the book might have been more enjoyable if Caroline sounded more like a young student; readers won’t buy, for instance, that the average teen would say, “I’m really surprised that even though I and just about all of my classmates know Einstein’s famous equation E = mc², which expresses the equivalence of mass and energy, I never knew about the photoelectric effect and his explanation—for which he was awarded the Nobel Prize.” However, DeLisi proves to be a superb teacher over the course of this book, and his explications, with accompanying graphs and charts (all well chosen, and never overwhelming), wonderfully demystify the many wonders of the everyday. British polymath Thomas Young’s famous double-slit experiment to determine the nature of light, for instance, is laid out with clarity while sacrificing none of its complexity. There’s plenty of technical jargon and specificity in these pages, but it’s all organized into prose that’s formidable but never intimidating. Also, although Caroline’s comments may seem unrealistic at times, DeLisi is careful to make her questions grow in depth and complexity as she ages, which neatly reflects the growing confidence his readers will have as they work their way through his primer. The book’s consideration of the complicated nature of Earth’s climate, and its surprising fragility in the face of human activity, is especially well done.

An effective conversational tour through some basic scientific realities.