Concepts and methods in the field of child development are understood better when observed or experienced, as opposed to described in a standard textbook or lecture format. We describe a live demonstration ill which commonly-taught developmental phenomena (e.g., Piagetian concepts, gender understanding, theory-of-mind abilities) are performed in front of a large class by children of several different ages. Students observe developmental changes firsthand and gain an appreciation for the methodological difficulties of conducting research with children. An immediate evaluation of the demonstration showed significant cognitive gains in students' understanding of the observed concepts, and a long-term follow-up showed self-reported cognitive and motivational benefits. Sample Tasks to Use in a Live Demonstration are appended. (Contains 1 table.)