Here are three easy ways to say it:
- A bruise is a dark mark that appears after you bump yourself. Tiny blood tubes under your skin get hurt and a little bit of blood leaks out under the skin.
- When you hit something and get a bump, sometimes a dark spot called a bruise forms. This happens because tiny blood vessels under your skin break and some blood goes under the skin.
- A bruise is like a colorful patch that shows up after a knock. Small bits of blood leak out from tiny vessels under the skin and make the color.