Abstract
A single human hair grows at the rate of approximately 9–12 mm/month. The combined effect of approximately 100,000 hair shafts produces a physical entity—the hair mass—which increases at a combined total of approximately 6 feet (1.8 m) an hour or 140 feet (46.67 m)/day. At a uniform length of 40 cm, this represents 40 km of hair carried on the head.