I have presented this type of project with great success with children as young as three. The first step is for the child to inspect her face in the mirror and describe what she sees. The she draws her face with the sharpie and paints with the liquid watercolor. The liquid watercolor creates a beautiful transparent wash over the black pen. Push pin or staple large sheets of paper to the side of a building or fence.
Kids spray at the paper with spray bottles, sharing and passing each color.
These spray painting make beautiful back drops in the studio or classroom for other art pieces. Spray ONLY the paper. Any child that blows the rule loses his turn.