The term inquiry has been used to form curriculum goals, design instructional strategies, and assess learning. The term also describes what scientists do. Within the science classroom, inquiry is used to promote activity-oriented learning that reflects scientific investigation—specifically the observation, experimentation, and reasoning used by scientists. Understanding the roles between content and process in school science helps educators better understand and practice inquiry-based instruction. This article discusses the differences between four aspects of instruction: content; content with process; process with content; and process.