Diameter of a Human Hair

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Edited by Glenn Elert -- Written by his students
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Bibliographic Entry	Result (w/surrounding text)	Standardized Result
Piezo Technology. Epson (UK) Ltd.	"45 microns, 2 times smaller than the diameter of a human hair and close to the limit of resolution for the human eye"	90 µm
Denny R's Homepage. Denny & Gayle Rossbach. Palmdale, CA.	"Diameter of a human hair inches: 0.001; centimeters: 0.00254"	25.4 µm
Why Choose A Water Treatment System? Aqua-Fresh Drinking Water Systems, Inc.	"Particulate contaminants including asbestos, rust, sediment, dirt, and scale as small as 0.2 microns (1/300th diameter of a human hair)."	60 µm
Hair - Important Facts About Hair. CAQTI Cosmetics, Inc.	"Flaxen hair is the finest, from 1/1500 to 1/500 of an inch in diameter … and black hair is the coarsest, from 1/450 to 1/140 of an inch."	17 - 50 µm (flaxen) 56 - 181 µm (black)

Hair can be found all over human body, except for the palms of hands and at the soles of feet. The purpose of hair is protective: the hairs on the body keeps a person warm, nose hairs prevent dust and dirt from entering the respiratory system, and eyebrows prevent sweat from entering the eyes.

The diameter of a human hair does not have a standard value since different people have different hair structures. Your genetic makeup can cause the width of your hair to differ from that of other people. Hair color is also a big factor. Black hair is thicker than is red hair. The weather can also affect the diameter of a hair strand. As the weather gets warmer, the diameter of body hair increases. Age is another factor. Babies and young children have finer hair than adults. As a person grows up, their hair becomes thicker and stronger. Another factor is that, the closer to the root of the hair, the thicker a strand of hair would be.

In my research, I have found the diameter of human hair to range from 17 to 181 µm (millionths of a meter).

Brian Ley -- 1999

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