This study aimed to explore how to characterize the earth science inquiry in schools in terms of science teaching interaction and constructivist teaching practice. The constructivist teaching practices were analyzed with Reformed Teaching Observation Protocol (RTOP) in three aspects including (1) student oriented class implementation, (2) subject knowledge and representation, and (3) classroom communication. Fourteen earth science classes were observed and scored with RTOP. The class was evaluated to be transitional stage in terms of constructivist teaching, e.g., moving toward student-centered teaching practice. Especially, Korean teachers tend to lean their classes more on propositional knowledge than procedural knowledge. To interpret science teaching interactions, an earth science teacher with a RTOP top rank was selected. Her class was then videotaped for detailed analysis. I adopted the analytical framework of communicative approaches and discourse patterns among the five aspects of interactions presented by Mortimer and Scott (2003). It was found that this earth science teacher used more authoritative patterns than the dialogic. In addition, she used IRE discourse pattern more frequently. Interestingly, teachers interacted with their students more frequently in the form of repeated (or IRE chain pattern), that is IRFRF (teacher initiation-student response-teacher feedback-student response-teacher feedback) in the context of dialogic communicative approaches, while simple IRE occurred in an authoritative approach. In earth science classrooms, typical interaction may well be constructed in the form of IRFRF chains to allow students free conjectures and abduction.