Evaluation is an important aspect of science and is receiving increasing attention in science education. The present study investigated (1) changes to plausibility judgments and knowledge as a result of a series of instructional scaffolds, called model–evidence link activities, that facilitated evaluation of scientific and alternative models in four different Earth science topics (climate change, fracking and earthquakes, wetlands and land use, and the formation of Earth’s Moon) and (2) relations between evaluation, plausibility reappraisal, and knowledge. Repeated measure multivariate analyses of variance (MANOVAs) showed that participants’ plausibility judgments shifted toward scientifically accepted explanations and increased their knowledge about relevant Earth science topics after participating in the activities. Structural equation modeling revealed that 10% of the postinstructional knowledge scores were related to participants’ evaluations, above and beyond background knowledge, which accounted for 26% of the variance. The activities used in this study may help students develop their critical thinking skills by facilitating evaluation of the validity of explanations based on evidence, a scientific practice that is key to understanding both scientific content and science as a process. However, results from the study were modest and suggest that additional research, from both theoretical and empirical perspectives, may be warranted.