Richard Benet, age 9, of Newport News, Virginia, for his question:

What colors a bruise?

A bruise is an injury to the soft flesh below the skin. Usually it happens when you get a nasty whack that is not quite hard enough to tear the skin or break a bone. But it does damage the tiny little cells from which the soft flesh is made. It also breaks some of the mini blood vessels that run throughout the soft flesh. This causes mini drops of blood to ooze out between the living cells.

When blood escapes from any large or small blood vessels, it soon turns dark and useless. When you get a bruise, there are tiny specks of lost blood in among the cells. This is what turns the flesh dark. But right away the body starts to heal itself. Bit by bit the tiny dark specks are toted away. In a few days the bruise becomes paler, then bluish yellow    and finally it fades away.