The stiffness or resistance to bending of individual hair fibres is likely to be one of the basic factors determining the firmness of a tress made up of an assemblage of all same fibres. Our interest was in exploring whether a useful relationship exists between physical measures of individual hairs and the bending stiffness of the lock of hair from which they were derived. The work was carried out on a chemically-untreated lock of a Chinese woman's hair comprising 399 individual fibres. We

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... red the diameter and the bending stiffness at a selection of distances along each hair from its root end. For each selected distance we found no correlation existed between the each fibre's cross sectional area and its bending stiffness at the same point. Similarly only a weak correlation existed between the moment of inertia of area at each point along the individual fibres and the corresponding bending stiffness. We believe the cause for this weak correlation was the inclusion of hairs with different Young's moduli. With this in mind we separated the hairs in the whole population into groups each of the same Young's modulus. These results suggested that the used hair bundle is composed by the groups of hair with a Young's modulus of at least seven. It was moreover found that if the measured was close to the tip of fibre, the number of fibres of lower Young's modulus increased. Guided by the above results, and to obtain reliable information about the bending resistance of the whole hair tress, we gained useful information by examining the distribution curves for each physical property. That is of the cross sectional area, moment of inertia of area, Young's modulus and bending stiffness arranged in ascending order.