I am delighted that ponytails are fashionable again. Runway models are sporting them on the catwalk. Betty Cooper is the original babe in ponytail. Jeannie sported a ponytail on almost every single episode of I Dream of Jeannie. And ponytails have even been a fashion trend for men (David Beckham anyone?).
I love fashion as much as science so how can I combine the two? Oh, I don’t have to? Scientists in the UK have published a paper in Physical Review Letters of their study of the physics of the ponytail. Jeannie’s ponytail spouted out of the top of her head, so that could make for some interesting physics reading right there.
The researchers hoped to predict the ponytail’s shape based on the properties of a single strand of hair. Looking at the stiffness, weight and curliness of the strand, they could predict the ponytail’s shape. Gravity played a role in pulling the hair downward, while the individual hairs had collisions between them, according to the scientists, that would cause the tail to swell outwards. Curly hair had greater collisions and a greater fan. I have straight, fine hair so my ponytail is a point (like a true thoroughbred!)
The various shapes of the ponytail are defined by their Rapunzel number, as the researchers named it. Funny, I don’t remember Rapunzel sporting a ponytail. Her hair was either down or in a braid. Oh well. The formula is this: the lower the Rapunzel number, the shorter and springier the ponytail, with the ends fanning outwards. The higher the Rapunzel number, the longer and more weighted the ponytail. I swear you do not need to study physics to figure this one out. Any woman having worn a ponytail since childhood could have told you this much.
But, how will this study tie in to the great big picture of being useful in the world? Apparently, this research will help in understanding bundles of fiberglass or wool. This research is also being hailed as aiding computer animators in producing more realistic human hair movement.