Reviews Physics World  May 2019
(Chris Hughes)

Coupled practices

Anna Demming reviews Physics and Dance by Emily Coates and Sarah Demers

“It was a shame the discussion was so focused on the extremes,” was a recurring comment among people who attended a recent panel discussion on interdisciplinary science that I went to. Many of the delegates were working at the interfaces between physics, chemistry and maths. While these fields operate in distinct cultural and linguistic landscapes, the disciplines are not separated by the kind of gulf that exists between physics and biology, which were the fields straddled by the panellists. These comments made me smile because I happened to be reading Physics and Dance by Emily Coates and Sarah Demers at the time. If the gap seems so huge between physics and biology, then physics and dance must be operating on different planets entirely.

Despite the apparent divide, Physics and Dance is not the only book seeking to explore common ground between these two disciplines. As an example, Coates and Demers cite Kenneth Law’s Physics and the Art of Dance, where the author eloquently describes the Newtonian mechanics at play in classical ballet. One characteristic that sets Physics and Dance apart is the breadth drawn on in the two disciplines, which not only includes the rudiments of mechanics and ballet, but also taps into the exotic irregularities of Einstein’s relativity and various more avant-garde movements in dance where fundamentally new philosophies are still emerging.

The result is neither a plodding account of conventional crossovers between physics and dance, nor is it a flight of fancy forcing dicey parallels of the most esoteric elements between the two fields. Instead, the book explores the evolution of dance, past and present, within a context of ideas that have developed in physics up to the current day; such that the reader is presented with a story that is still unfolding.

I found Physics and Dance a fascinating read. It handles both disciplines in a refreshingly egalitarian way that doesn’t just position them as commanding equal respect, although there is a sense of this too. For example, in the discussion of momentum, the authors describe it as something that “influences everyone but few people know how to wield the effects as virtuosically as dancers and physicists”. However, Coates and Demers take this equality further by demanding equal engagement from their readers with both disciplines. They allow equations to infiltrate explanations in a way that many pop-sci authors shy away from – indeed, they even provide physics problems for readers to enjoy playing with the ideas just described. Similarly, there are movement exercises that allow readers – from all levels of dance experience – to “feel” physics in action from the perspective of a dancer. And lest you kid yourself into reading these as mere “thought experiments”, Coates and Demers introduce these exercises with the instruction “put this book down”.

What emerges are ideas that don’t hop from the paradigms of one discipline to the other but share these paradigms at a fundamental level like the DNA of a newly fused zygote; and the potential outcomes feel exciting. I got goose bumps from the comment “It’s time to bring trigonometry to dance”, but what really got me hooked wasn’t simply reading how physics determines how dance movements work. Instead, by paying close attention to a YouTube clip, remembering your A-level physics and applying a bit of thought, you can reach a lot of those conclusions without the unique combined expertise of the two authors. Demers is a particle physicist working on experiments at CERN, while Coates is a dancer whose career has included work with choreographers such as Jerome Robbins, Mark Morris and Erick Hawkins, and performing alongside New York City Ballet and the likes of Mikhail Baryshnikov.

What really fascinated me in this book is reading about the role of cultural forces, akin to mechanical forces, in dance evolution; or how dancers have subconsciously drawn on both dance and physics aesthetics to develop movements, like George Balanchine’s form for a pirouette. For this, Coates and Demers take us to the studio where this form was born to witness the moment of creation as choreographer Balanchine presses soloist Suzanne Farrell to adjust the technique she has grown up with further and further until she is convinced she is being set up to fail. Instead, Farrell pulls off “the most glorious pirouette she had ever felt”, thanks to Balanchine’s masterful handling of torque.

Dancers have subconsciously drawn on both dance and physics aesthetics to develop movements

While Coates and Demers do include other physics topics, a lot of the book is devoted to mechanics, taking readers steadily through the basics. Parts of this discussion could be a bit of a yawn for people already familiar with these ideas. Readers with a background in physics might therefore be tempted to skim some of these sections, and there may be parts that don’t do a lot for anyone – the discussion of units will be old news to the initiated, and won’t be relevant or enthralling for those new to the idea. However, I would argue that most of the book retains appeal for all. The language is rich: air doesn’t just occupy the region directly above sea level, but “hugs the Earth” as a result of the same gravitational force that stops us flying off the planet. Twyla Tharp is not just a choreographer but an “alchemist of motion”.

Physics and Dance is essential reading for those with an avid passion for both topics. It should also appeal to the many dance professionals who have a fruitful muse in science. After all, the idea that the human body should play a role in the physicist’s search for fundamental laws has been bandied about for centuries – optics pioneer John Tyndall is just one example. As Coates and Demers put it: “People feel sensorial engagement with friction that boxes don’t,” adding that, at the same time, “In dance, friction produces meaning.” Reading Physics and Dance is an insightful reminder that the two disciplines have developed on the same planet after all, and that exchanging ideas that encompass them both is definitely worth the effort.