WHAT WE DO SEE : THE SHAFT

We have a very special relationship with our hair and are always surprised, even shocked, to learn that the part we see which goes to make up our precious head of hair is in fact, biologically dead. Furthermore, it receives no further assistance from the root which created it. However, the hair fibre does have an absolutely remarkable structure.



  The hair in figures
Hair is a genuine individual and an individual can't be summed up in a few figures. That being said, vital statistics can sometimes be useful. However, since every hair and head of hair are absolutely unique, the figures on this ID card are of course only averages.

  • 58 to 100 microns - the diameter of a single hair. However, since the cross section of a hair is elliptical, the term diameter is not totally accurate .
    A micron is one millionth of a metre, or one thousandth of a millimetre - it therefore takes 10 to 20 hairs "piled up" together to obtain a thickness of one millimetre.

  • 120,000 to 150,000 - the number of individual hairs in a full head of hair.

  • 250, the number of hairs per square centimetre of scalp. This figure varies between 200 and 300 according to the area of scalp in question

  • 6 m2, the total surface area of a head of hair 20 centimetres long. This is an important figure, as when shampooing for example, this is the surface which must be washed.
    Since the surface area of the scalp is 600 cm², a head of hair 20 centimetres long therefore occupies an area 100 times greater than its place of origin.

  • 1.3 grams,the weight of 1 cm3 of hair..

  • 5 to 200 grams the weight of a head of hair according to the length of the hair making it up.

  • 30% of its own weight , the percentage of weight in water that a hair in good condition can absorb. If it has been weakened, this percentage can reach 45%

  • 1 cm per month, the speed at which hair grows. This corresponds to a daily growth rate in excess of 0.3 mm per day and an annual growth of 12 centimetres per hair.
    By applying these figures to the entire head of hair, we see that it is produced at the rate of more than a 36 metres a day, some 1.1 kilometres per month, or more than 13 kilometres a year!
    In terms of weight, for an entire head of hair this represents 0.2 grams per day, 6 grams a month or 72 grams a year.

    Since hair grows from its roots, the tip of a hair 12 cm long will be one year old. But as a single hair has on average a three year growth cycle, it is rare to see hair longer than one metre, which represents over eight years of growth However, the world record for hair length stands at 4.2 metres. If this hair had grown at a normal rate, its tips would be 35 years old!

  • 50 à 100, the number of hair we naturally lose each day

  • 100 grams, the weight a single hair can withstand.
    A strand of 100 hairs would therefore be able to resist a weight of 10 kilos. And if the scalp were sufficiently resilient, an entire head of hair could support 12 tonnes!

  • 50% of its initial length, the percentage a hair can stretch before it severs. In other words, a hair 30 centimetres long could become 15 centimetres longer before breaking.

  • Three times a week, the average frequency for washing hair in Europe. One quarter of the population shampoo their hair every day.

  • 80% of North Americans and 90% of Japanese wash their hair twice a day.







WELCOME
PORTRAIT OF AN UNKNOW ELEMENT

WHAT WE DON'T SEE : THE ROOT

WHAT WE DO SEE : THE SHAFT

SUPERB CHEMISTRY

WELL BEFORE BIRTH
LIVING AND RELIVING
AMAZINGLY NATURAL
SO STURDY AND YET SO FRAGILE
INFINITE TRANSFORMATIONS
THE HAIR A SCIENTIFIQUE ENIGMA
HAIR AND CULTURE
EXHIBITIONS
TOOLBOX







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