This is an instructional module designed to introduce learners to the concepts of uncertainty in experimental research, random error, and systematic error. The authors use a contextual approach, with multiple examples drawn from real life. For example, “”accuracy”” and “”precision”” are defined from the context of a biathlon competition. Statistical error is presented within a vignette of W.F. Libby’s 1946 experiments on carbon-14 dating. Systematic error is described through a 1993 experiment by Edward Lorenz on mathematical modeling for predicting weather. This item includes test questions and links to external resources. This resource is part of Visionlearning, an award-winning set of classroom-tested modules for science education.