Energy spreading or disorder? Understanding entropy from the perspective of energy

Abstract

Scientific explanations for the cause of spontaneous processes can be understood from the energy perspective. The second law of thermodynamics shows that all real spontaneous processes lead to an increase in the total entropy of the universe. Entropy is closely related to energy, though the two concepts are distinct. In K-12 science education, students should gain familiarity with explanations for the cause of spontaneous processes. This includes a qualitative understanding of the second law of thermodynamics and entropy, as well as an understanding of the relationship between entropy and energy. Here, we review the energy dispersal metaphor for entropy and the energy spreading metaphor for entropy change, and describe how these metaphors can provide students with a scientific understanding of spontaneous processes from the energy perspective. We also discuss advantages of using this metaphor over others for teaching and learning about entropy in K-12 science education, such as the metaphor’s compliance with the features of entropy, the avoidance of common misconceptions when using the metaphor, the metaphor’s accessibility to students at a young age, and the metaphor’s amenability to updating for increasingly sophisticated understandings of entropy. We also discuss why the commonly used disorder metaphor for entropy should be avoided. Finally, we propose a potential K-12 learning progression for understanding spontaneous processes from the energy perspective.