The objective of the present work is to have a closer look at the relations between the features of discovery simulations, the learning processes elicited, the knowledge that results, and the methods used to measure this acquired knowledge. It is argued that discovery simulations are ‘rich’, have a relatively low transparency, and require active involvement of learners. Discovery simulations are suited to support data-driven, partly implicit learning. Discovery learning leads to intuitive knowledge. To complement this conceptual investigation, a series of five experimental studies is described. In all five studies, learners were pre-tested and post-tested with several knowledge measures. Central to the set of tests was one with the objective of measuring intuitive knowledge. One conclusion of these experimental studies is that assignments contribute most clearly to the instructional effectiveness of simulations. Another conclusion is that the intuitive knowledge tests seem able to measure the results of learning with discovery simulations.