Additional Math Pages & Resources

Thursday, February 3, 2011

Hair today, gone tomorrow Part II

Today I will focus on math related to the hair on our heads.

No doubt you have heard the phrase "as thin as a human hair". How thin is that?

It depends on your ethnic origin. Hair thickness ranges from .04 to .25 mm - on average it's about one-tenth of a millimeter or .1 mm. [Click for a larger image]
Thicker hair emerges from large hair follicles - thickest tend to be red/orange and dark or black hair. Finer hair comes out of smaller follicles and tends to be lighter or blonde. We don't know for sure if this is genetic.

Of course we've been talking about a hair from the top of your head. If you haven't already noticed, ear hairs, nose hairs, moustache and beard hairs can be much thicker.

Our hair follicles have a self-regulation function that determines how long their hairs should be. Eventually hairs stop growing, fall out, and a new hair emerges. But not always. Sometimes it keeps growing.

Here's a young lady named Xia Aifeng, in China. Her hair is 2.75 m (9 ft) long. You can search for her on YouTube and watch her washing, combing and throwing her hair around.

As we get older, the regulation system may stop working on a few of your follicles too. That's why some older people have long ear and nose hairs. How long? I checked at the Guinness World Records site:
  • Toshie Kawakami in Japan has one eyebrow hair 17.8 cm (7.0 in) long
  • Anthony Victor in India has ear hairs 18.1 cm (7.1 in) long
  • Richard Condo in the USA has chest hairs 22.8 cm (9.0 in) long!
If this seems gross, just wait. It could happen to you!

Notice that so far we are only talking technical details about our existing hair(s), with nothing said about removal, hair styling and coloring, or hair loss. Those are subjects full of math as well as emotional risk! Maybe something for another blog...

If you are interested in more details about your hair, you might want to visit the Hairfactz site.

As for me, I'm going to have lunch and go get my hair(s) cut.