While scientific argumentation has been a robust topic in the research literature, much of the evidence from this area has been on learning science through text. This study was designed to analyze how individuals generated scientific evidence following engagement in a web-based global climate change simulation. Prior to engagement in the simulation, 70 undergraduate participants completed measures of prior knowledge, engaged in the simulation, and answered open-ended outcome questions where they were asked to provide evidence. Results supported the contention that evidence generated explicitly from the simulation was higher in both its clarity and relevance, and further, that prior knowledge had very little effect on the quality of the evidence provided, whether the evidence was from the simulation or not.