This collaborative project is investigating the characteristics of a mixed-reality learning environment that combines the rich context and multi-sensory experiences of a physical lab with the interactive simulations of a virtual lab. The hybrid environment integrates sensors and simulations to bring out the advantages of each setting in a complementary way. The research team is developing four such mixed-reality laboratory experiences for secondary school level chemistry and physics courses and studying student learning in these contexts. Two of the activities use an integration strategy in which data acquired in real time from a physical experiment are used to control a virtual experiment. The advantage of this coupling is that abstract concepts or invisible processes can be visualized on the computer screen while the physical experiment is underway. Whenever the learner's hands-on interaction with the physical experiments changes the sensor measurement, the visualization in the virtual experiment responds accordingly, creating an intimate link between the two worlds. The other integration strategy uses physical and virtual experiments in parallel, challenging the student to match the results measured by the sensors and the results computed by the simulations. The learning potential in this configuration stems from the ability to go back and forth between both worlds, adjusting the virtual experiment to match the physical experiment and then adjusting the physical experiment to test the fidelity of the virtual experiment. Implementations of the four activities in eight classrooms are being compared to classes covering similar content. The intellectual merit of this project lies in its investigation of the potential of cyberlearning technologies to transform inquiry in the lab. In addition, the project brings to bear the expertise of a recognized team of researchers. The project is exercising its broader impacts through its identification of a new instructional approach to STEM education. The combination of physical and virtual labs carries the potential for broad utility, with the insights and examples developed by this project potentially applicable throughout STEM education. In fact, because all of the project software is open source and the materials made available freely from the project's website, the only expenses to schools are for the sensors. A key design criterion is that all project software is compatible with sensors from multiple vendors so that schools are not limited in their choices.