Critique and evaluation are considered essential to deeper science learning. Furthermore, critical evaluation may influence plausibility judgments about explanations through re-appraisal. We developed the YIS-activity (blinded for peer review) to activate students’ epistemic judgments (i.e., plausibility) about competing models explaining scientific phenomena and to further their learning about Earth science topics. This study seeks to answer the question, “How are the plausibility shifts and knowledge gains of students impacted by the evaluation of multiple explanatory models for the future availability of freshwater resources?” Participants (N=76) completed a YIS-activity about freshwater resources, including pre and post-instruction knowledge surveys and plausibility ratings. Paired-samples t-tests determined that the students showed significant knowledge gains [t(75)=4.46, p<.001, d=0.51]. Initial analysis of the omnibus plausibility shifts was not significant, however particular knowledge item score differences caused us to re-evaluate the plausibility relationships between the three presented models. Two models each showed significant differences with the third model, [t(75)=2.66, p<.001, d=0.30] and [t(75)=2.94, p=.004, d=0.33] respectively. These two models also did not have a significant plausibility shift between themselves. While students accomplished significant learning in the YIS-activity, this finding emphasizes the difficulty that students have when evaluating multiple scientific explanatory models. This presentation was prepared for the 2020 Annual International NARST Conference.