Hair, identity, science, soul

The Physics of Hair

We all know (or are learning) that wavy and curly hair is drier than hair that is straight. That straight hair gets natural oil all the way down the shaft, whereas hair with bends or twists can’t get the same benefits.

And we spend time thinking about our own curl patterns, or at least I do. I spent a lifetime with poofy hair and am in the process of letting my hair figure out what it wants to be. Tight dreadlock-style twists, rolls at my roots, s-waves that end in scythe-like hooks are separating from my hair’s undifferentiated fine bulk, finding friends with the same inclination. Two-dimensional patterns become three.

It’s physics, a balance in time and space. And physicists have actually studied it.

Physicists have never had very good computer models to represent how a curled strand of a flexible material behaves, which is one of the reasons the characters in computer animated cartoons tend to have straight hair. (Kudos to Pixar for giving it a go in Brave). But there’s more than cartoonery at stake in this particular curling event; industrial manufacturers are affected too.

Weight is the main issue, because the longer the hair, the greater the burden on the end. Shorter curly hair can move in its own directions, but with the addition of weight the system of movement becomes more complex, a “3D global helix,” in physics-speak.

And every person with curly hair has a different underlying pattern and structure, all those variables we try to control for as we find our perfect regimen and product combos—thickness, density, the pliability of each strand and its weight.

The researchers reduced all of these variables to algorithms, created models, and found they could predict the behavior of any type of strand, from the range of human hair properties to industrial metal.

Sure, all this helps in industrial design and engineering. But it also helps us understand the dizzying complexity of our own daily physics experiments. On any given day, we are wrestling to predict and control for the behavior of a “complex, chaotic system” that keep teams of physicists and computer models churning to get ahead of.

I don’t know about you, but for me, that puts bad hair days into a bit of perspective. It also makes me feel like I’m not doing too badly as I work through my hair’s identity issues.

Laura