This study aimed to understand students' views of the nature of model evaluation and the nature of change of models in different context. A total of 102 eighth graders and 87 eleventh graders were surveyed. Two cases, the SARS and dinosaur extinction, were presented to prompt students' ideas about different models proposed by scientists. The statistical results showed different context of the model influenced how the students viewed model evaluation and model change. The students' answers also showed significantly differences between the high school level and the middle school level for their views of model change. The common reasons behind students' choice were related to students' understanding of the changeable nature of model and the science process. The students who chose that "one model is better than another" tended to justify their response by their understanding of the content. Interestingly, some students' views of the dinosaur extinction model were guided by their beliefs that information about the dinosaurs is unfathomable. The findings suggest that researchers should be aware that the models chosen for teaching and for assessment can interact with other factors, such as their familiarity of the content, their level of education and understanding of the nature of science. The results from written responses were further used to develop a multiple-choice survey and validated in the follow-up study.