Mathematicians prove the best way to get tangles out of hair is to start brushing at the ENDS

Anyone who has ever had to brush long hair will know that trying to get the knots out can be a nightmare. But mathematicians have now proved what many have suspected for some time – that the key to freeing the tangles is beginning at the ends and moving upwards the roots. Harvard researchers created a model that simulated two helically entwined filaments (similar to a strand of DNA) to represent a tangle of hair, and analysed different ways of'brushing' it so the hairs became free. Their results, published in the journal Soft Matter, revealed short brush strokes that start at the'free' end of the hair and move towards the'clamped' end are most effective. Experiments and simulations show the'tine' (representing a prong of the brush) moving along the double helix from the clamped end towards the free end'Using this minimal model, we study the detangling of the double helix via a single stiff tine (prong) that moves along it, leaving two untangled filaments in its wake,' said Plumb-Reyes, a graduate student at SEAS. 'We measured the forces and deformations associated with combing and then simulated it numerically.'