Earth science teachers' knowledge of the water system and Its reflections in their lesson plans.

Abstract

Over the last two decades, scientists have recognized the necessity of studying the earth as an integrated system. Consequently, the knowledge of physical earth systems and human interactions was integrated to form a new discipline, Earth System Science (ESS). Given the acceleration of environmental change, such as that of the global climate system, understanding the earth as a system has become essential in order to create a scientifically literate citizenry. However, our understanding of teachers' and students' conceptual understanding of earth as a system is still in its infancy. Due to the interdisciplinary nature of the ESS discipline as well as the complexity of the ESS knowledge structure, there is no consensus about important ESS knowledge for teachers or students. This study presents an analytical framework, Earth System Knowledge Framework (ESKF), to assess teachers' conceptual understanding of earth systems using the concept of water. By utilizing the framework, this study investigates five secondary earth science teachers' conceptual understandings of water in earth system. This study also probes how the teachers' conceptual understanding of water in the earth system affects their selection and organization of the topics and related content knowledge for lesson planning. Through intensive interviews with the teachers, this study employs multiple case studies using inductive and qualitative analysis methods. The findings of this study demonstrate that the teachers' conceptual understandings of water in earth system are highly related to their Earth System Knowledge (ESK). Furthermore, the science teachers' conceptual understanding of water in earth system directly affects the topic choices and content knowledge used for teaching the concept of water. This study implies that the teachers not only need to possess knowledge of physical earth systems but also knowledge of earth's biosphere and ecosystems to understand earth as a system. This study also suggests a need to reform teacher preparation in a way that the teachers could gain basic and fundamental knowledge of earth system and elaborate their skills to apply earth system knowledge for teaching.