In this chapter, the words "What color is inside?" appear around a hole on top of a can. The outside is multicolored, indicating that any of a number of colors could be inside. If students look through the hole, it appears that the inside is painted black. This challenges students to determine what color is inside without prying off the lid. When the color is revealed, students gain insight into the nature of the perception of light, color, and what is needed for eyes to see. Many students have a common misconception about light. This demonstration is applicable to a wide range of students, starting as early as those in the 4th grade.