This article examines how children's construction of relationships in exploring materials helps to explain the constructivist foundations of the Reggio Emilia approach. A quasi-naturalistic study of 12 preschool children, ages 3 and 4 years, individually exploring different kinds of collage papers reveals a range of constructivist categories including physical knowledge responses, mental relationships, and symbolic representation responses. The results show that as children explore the physical properties of media, they become more familiar with the affordances, or capacities of materials. Development across the ages of the group progresses from the children's exploratory actions on the objects to their increasingly more complex relationships to support a range of emerging representations--props of symbolic play, letters of the alphabet, and stand-alone artistic representation. These constructivist underpinnings emphasize the origins of Reggio Emilia's relational pedagogy and support today's playful relationships with all of the elements of art. (Contains 2 tables, 1 figure and 4 footnotes.)