It is now widely accepted, and indeed emphasized in the Next Generation Science Standards, that science education should encompass scientific practice as well as science content. By participating in an intellectual community engaged in the broad range of activities that constitute scientific inquiry, rather than simply mastering isolated science procedures, it is hoped students will come to better understand and appreciate the norms, goals, and values that govern the conduct of science. We put this expectation to empirical test by engaging a secondary school science class in an extended problem-based activity that included design of investigations, multivariable causal analysis, and argumentation. Compared to students in a nonparticipating control group, in delayed assessments involving new content, participating students showed more advanced investigation, analysis, and argumentation skills, but also superior epistemological understanding regarding science as entailing the evaluation of claims in relation to available evidence.