Contemporary science education themes are marked by the inevitable uncertainty of consequences emerging from human actions. They encompass disasters, pandemics and other events that have been marking our present times. Understanding new risks as the ones resulting from human action, even when proposing a solution for an issue, is one of the central assumptions of the Risk Society theory. Given the challenges of teaching about uncertain scenarios, in this work we address ways for dealing with science teaching situations in which unpredictable events are the rule. We report a teaching and learning sequence implementation in the 9th grade of a Brazilian mid school, using a real case of disaster to develop a didactic approach accounting for human-made risks. In this work we aimed to explore strategies for preparing teachers to deal with the inherent uncertainty of risk situations, overlapping semantic network analysis, risk matrix construction and its collective evaluation with. rounds of discussion and emphasizing the risk-confidence paradigm over the traditional hazardsecurity perspective. Our results show evidence of students' appropriation of the notion of manufactured risk by enacting complex causal relations in unpredictable scenarios, something also reflected in their utterances and in their pattern of choice during risk matrix building.