Imagine a student-teacher in front of a classroom, trying to get control of the classroom. A student might pull out his phone or make a comment that disrupts the rest of the class. The prospective teacher will then use classroom-management techniques that she has learned in her own classes to re-engage the students in the lesson. Nothing out of the ordinary. But at UVA’s Curry School of Education, that classroom is a computer-based mixed-reality simulation. The students are avatars, programmed to be unruly to test prospective teachers' classroom-management skills.