Rachel Crotti, age 1 2, of San Francisco,CA., for her question

Why doesn’t it hurt to cut hair?

When you cut a finger, you see blood and feel pain. The blood oozes out from the fine capillary blood vessels in the soft fleshy tissues. Also in these tissues is a network of nerves. These nerves carry a message of the damage to the brain and you feel pain. The hair on your head has neither blood vessels nor nerves.

When you cut it, it does not bleed and you do not feel a thing. A thread of hair is made of dry, dead cells, very different from the living fleshy tissues. It hurts to pull out a hair because nerves in the fleshy scalp are jerked. But hair cannot hurt when it is cut because it has no nerves to send an alarm message to the brain.