Students’ Scientific Evaluations of Astronomical Origins

Students often encounter alternative explanations about astronomical phenomena. However, inconsistent with astronomers’ practices, students may not be scientific, critical, and evaluative when comparing alternatives. Instructional scaffolds, such as the Model-Evidence Link (MEL) diagram, where students weigh connections between lines of evidence and alternative explanations, may help facilitate students’ scientific evaluation and deepen their learning about astronomy. Our research team has developed two forms of the MEL: (a) the preconstructed MEL (pcMEL), where students are given four lines of evidence and two alternative explanatory models about the formation of Earth’s Moon and (b) the build-a-MEL (baMEL), where students construct their own diagrams by choosing four lines scientific evidence out of eight choices and two alternative explanatory model out of three choices, about the origins of the Universe. The present study compared the more autonomy-supportive baMEL to the less autonomy-supportive pcMEL and found that both scaffolds shifted high school student and preservice teacher participants’ plausibility judgments toward a more scientific stance and increased their knowledge about the topics. Additional analyses revealed that the baMEL resulted in deeper evaluations and had stronger relations between levels of evaluation and post-instructional plausibility judgements and knowledge compared to the pcMEL. This present study, focused on astronomical topics, supports our team’s earlier research that scaffolds such as the MELs in combination with more autonomy-supportive classrooms may be one way to deepen students’ scientific thinking and increase their knowledge of complex scientific phenomena.