# A description of the shape of a hairstyle in the form of a tail from the point of view of physics is given.

A group of scientists from the University of Cambridge and York have developed a unique theory that describes the shape of the ponytail. The results of the physicists’ work are published in the scientific publication Physical Review Letters.

Since on average there are about 100 thousand hairs on a person’s head, a special apparatus of statistical physics was used to describe the shape of a hairstyle in the form of a tail. Each individual hair was studied as an elastic thread that had a randomly defined degree of internal curvature. A total of 115 individual hairs were examined, after which the scientists obtained an overall distribution of curvature.

Based on the calculations made, physicists managed to derive a special formula that describes a hairstyle in terms of the action of gravity, hair elasticity and the degree of curvature. Additionally, for the convenience of calculations, certain dimensionless numbers were introduced, which were named Rapunzel numbers. Dimensionless numbers characterize the ratio of the length of the hairstyle to the size of its cross-section.

As the scientists themselves say, the resulting formula is widely used not only in relation to the hairstyle, but also in relation to the bundle of elastic threads. Also, the research of physicists can become the basis for the development of a new theory that will characterize the dynamics of hair bundles or threads.