Arrange the Blackboard Optics single-beam light source, prism, and
projection screen as shown at left. In a sufficiently dark room,
the dispersion pattern shown at right is clearly visible to a large class.
The ray box requires 10 or 12 V AC. The Blackboard Optics Transformer
shown below provides this. The room needs to be dark in order for
the rays to be clearly visible to a large class.
