Print PageUnderstanding carbon cycling will be a crucial part of public environmental literacy in an era of climate change. However, students graduating from high school have trouble evaluating and contributing to scientific discussions about the global carbon cycle and human intervention in that cycle. From prior work we know that students have difficulty with processes (photosynthesis, respiration, biosynthesis, combustion) and principles (conservation of energy and mass) necessary for understanding carbon cycling and energy flow. We are testing the effectiveness of teaching strategies designed to address these learning challenges using classroom teaching experiments coupled with pre- and post-assessments. We are also evaluating, through written assessments and interviews, student and teacher interpretations of different graphical models of the global carbon cycle.
Results/Conclusions
When asked to explain familiar processes such as plant and animal growth, students frequently refer to the needs and “natural tendencies” of organisms or objects rather than relying on principles of conservation of energy and mass. For example, students frequently link plants and animals in a mutually fulfilling “carbon-oxygen” cycle. Preliminary results show that guided inquiry activities involving observing and measuring gas exchange and biomass gain in plants can help students to challenge these informal accounts and begin to build scientific explanations. Tracing carbon through basic processes such as photosynthesis and respiration is also a foundation for interpreting carbon cycle diagrams and understanding the dynamics of the global carbon cycle. Preliminary results show that students and teachers can use a simple stock-flow box-model diagram of the global carbon cycle as a tool to construct and quantitatively evaluate carbon emissions reduction strategies, a task that has been shown to be extremely challenging using other graphical representations.
