Students often learn about measurement uncertainty as an isolated topic, with a focus on generalizable strategies to manage uncertainty in scientific investigation. In this study, we report and analyze a case of emergent learning about measurement and uncertainty, in which students in a Chinese elementary school science class explored and reconciled discrepancies in hypotheses by constructing and using measures and making inferences. Adopting a model-based view of measurement, we show that when allowed to take on emergent measurement uncertainty while inquiring into causes for phenomena, late elementary students with no prior experience can engage in sophisticated reasoning characterized by a variety of theoretical modeling practices. Developing and aligning models of the phenomenon, the measure and the measurement data supported students in constructing an intuitive solution to their discrepancies. Our analysis also identified (1) a pattern of thinking and some common assumptions students adopted in their modeling practice that were productive, and (2) contextual elements affording and constraining emergent learning on measurement and uncertainty. In our discussion, we reflect on the educational potential of adopting a model-based account of measurement and of treating measurement and uncertainty as integrated into investigative practice. We also discuss the necessary contexts for realizing the potential of the model-based account.