Part of the show Science of Sound, Music and Voices
Bobby Car asked:
Why does your hair turn grey as you get older?
A hair is made of keratin which is the same protein that makes up finger nails which is white. On your head you have a group of cells specialised for making keratin, and near them you other cells called melanocytes which make the dark browney black pigment called melanin (its job is to absorb ultra violet light and protect the skin) a lot of these keratin making cells are squashed flat and painted with pigment, squirted through a nozzle called a folicle and form a hair. Sometimes for reasons that are not well understood, these melanocytes seem to burn out leaving the hair its natural white colour. Grey hair is actually a mixture between normal dark hairs and white hairs, which if you are standing a way away look grey.