Why does the sun lighten our hair, but darken our skin?

Why does the sun darken the skin but lighten the hair?

• How come the sun tans the skin but it causes the hair to lighten???

• Answer:

  The UV light in the sun is more powerful than regular light, and it can damage chemicals a little at a time by zapping them. This is why plastic gets crispy when left outside for a couple months. UV zaps the proteins that provide color in your hair and so they end up less able to absorb regular light and so get lighter (and probably more clear). UV zaps the proteins and DNA in your skin cells, which harms them. Have you ever noticed that women that tanned a lot in high school and after look all leathery and wrinkled later in life? Well, the skin is alive and responds by making MELANIN, which is a new pigment that will absorb the UV instead of the other chemicals in the cells that would be damanged by it. The melanin is damaged, but that's OK since its function is to get damaged instaed of other stuff. The difference is that the skin is alive and the hair is dead. The skin cells produce pigment in response to the sun (or even worse, in response to the wrinkle-radiation of tanning beds) to protect, while the hair isn't alive any more and so cannot make new pigment.