physics of dance :Judy Kupferman's Interview with Prof. Ken Laws
By Judy Kupferman

Judy Kupferman is a leading Israeli lighting designer who has worked in hundreds of productions in theater, dance, son-et-lumiere and more. She is on the
faculty of the Theatre Department at Tel Aviv University. Email: kupfer@post.tau.ac.il

Few areas seem as far removed as physics and classical ballet. And yet on closer examination they have certain aspects in common. Both require unusual and ceaseless effort. Both rely on a formal language difficult to acquire. And both contain a beauty that is powerful and abstract. Nevertheless most physicists know little of the ballet, and surely ballet fans and professionals have had little or no contact with physics - until Ken Laws came along.

Kenneth Laws is a professor of physics who became interested in classical ballet to a degree that led him to study it, teach it and eventually research it in physical terms. He has done much work in bringing these unrelated fields together. He has written three books on the physics of dance, and given talks and presentations to those involved in physics as well as dance. He is currently engaged in research on jumps, using quantitative measurements to determine the forces exerted on and transmitted through the body, which bring it to rest on landing from a vertical jump.

I thought, "This is impossible! The center of mass moves to the side when the leg moves in that direction, and the area of support at the floor is no longer directly below it. So we would have to topple." Well when I looked around, all the kids in the class were doing it! They somehow had figured out that they could "cheat" in little ways that allowed them to appear to meet the challenge. I doubt that they were thinking about where their centers of mass were, or where the forces and torques might come from to maintain a balanced static equilibrium, but their bodies, by trial and error or instinct, had figured out what to do! And one of the lessons I learned was that much of dance is illusion. There are indeed physical constraints that dancers appear to defy, some dancers more effectively than others.