This paper reports empirical evidence on having students use AR-SaBEr, a simulation tool based on augmented reality (AR), to discover the basic principles of electricity through a series of experiments. AR-SaBEr was enhanced with knowledge-based support and inquiry-based scaffolding mechanisms, which proved useful for discovery learning in Web-based simulation environments. Learning performance factors evaluated included students' learning behavior while interacting with the system, AR-SaBEr's learning effectiveness, and students' motivation in using the AR-based simulation environment. The study suggests that AR simulators can be exploited as effective learning environments for learning the basic principles of electricity. It would, however, be necessary to consider a number of scaffolding options to improve the learning effectiveness of AR-based simulation environments when used with students who have low levels of either: (1) self-regulation skills, or (2) motivation to engage in AR-based simulation activities.