Process-oriented inquiry can help preservice and inservice early childhood teachers implement constructivist science education in their own classrooms. In this article, we discuss the basic elements of process-oriented inquiry applied to early childhood science education, show how we foster the development of process-oriented inquiry teaching skills with our preservice early childhood education students, and argue that the validity of children's conclusions is more important than right or wrong answers. (Contains 2 figures and 1 table.)