This lesson plan helps students understand the role consumer demand plays in the market system, i.e., how interactions in the marketplace help determine pricing. Students will participate in an activity that demonstrates the concepts of demand, demand schedule, demand curve, and the law of demand. The lesson plan provides student objectives; offers a description of the activity; suggests a time duration; lists supplies needed; and outlines a step-by-step teaching procedure. It includes a homework assignment that requires students to conduct a survey of 10 students (not in the class) to determine the demand for a certain item. (BT)