- 27 September 2014 -
On the surface, when you watch ballet dancers gracefully move across an empty stage filling it with their passion and emotion, it almost gives the impression that dance is quite effortless. Even after hours of endless rehearsals and tiring performances, ballet dancers make everything look calm, collected, and strong. On the other hand, when you first set your eyes on the first Physics problem on your first year LonCapa assignment, it is almost as if Physics is a whole different language, impossible to understand.
Out of all the styles of dance in the world, why does physics relate with ballet the most? It is the foundation of most if not all dance forms with its origins in the Italian Renaissance courts of the 15th and 16th centuries (Laws and Harvey, 1994). The truth is, ballet is one of the most difficult types of dance to master in contrast to other dance styles such as jazz, contemporary, acrobatics or even hip-hop. The reason behind this intriguing reality is simple. Ballet is Physics in action. To become a great ballet dancer, you must learn to master a handful of main physical concepts namely, balance, inertia, torque, centripetal force, parabolic motion, angular velocity, angular momentum, and friction (Laws and Harvey, 1994) while actively applying these concepts to your flexibility and muscle memory. For advanced ballet dancers, these are all done using a pair of hard, boxed-shaped platforms measuring 5 centimeters in diameter called pointe shoes (refer to Figure 1 below).
The most popular dance move known by ballet dancers and even the world of non-dancers is called a “pirouette”. A pirouette is a French word meaning to “whirl or spin” and it is a complete turn of the body on one foot (Hep.uiuc. edu, 2000). This ballet movement is the perfect presentation of the physics concept, torque, which is defined by the equation:
where r is the distance between the front and the back leg when straddling or preparing for a pirouette (Laws, 2002). With this, the back leg pushes off of the floor and provides a magnitude force, F, which also corresponds as the axis of rotation, θ (usually 180°) .
In a pirouette (refer to Figure 2 below), a dancer has to keep in mind a variety of other forces acting on him or her. An example is the force of friction between the dance floor and his or her shoes and the centripetal force causing rotational inertia, which is affecting her overall turning velocity and stopping position.
Overall, ballet dancers do not only develop and enhance their physical abilities but their mental strength as well, as proven through Physics. The reason for this is because dancers must think of their rotational inertia and velocity during a turn, their displacement in the air in the midst of a jump or ever the friction between their shoes and the textured stage. They may not look like it but dancers are acquired physicists in action as they make dance look effortless and picturesque.
Ballet is indeed Physics in constant action.
References:
Hep.uiuc.edu, (2000). The Physics of Dance. [online] Available at: http://www.hep.uiuc.edu/home/g-gollin/dance/dance_physics.html [Accessed 26 Sep. 2014].
Laws, K. (2002). Physics and the Art of Dance. 1st ed. Oxford: Oxford University Press.
Laws, K. and Harvey, C. (1994). Physics, dance, and the pas de deux. 1st ed. New York: Schirmer Books.