How does a one-way mirror work? Though most everyone knows that one-way mirrors exist, having students model how they work turns out to be a very effective way to develop their thinking about how visible light travels and how we see images. Initial student models reveal a wide variety of ideas and explanations that motivate the unit investigations that help students figure out what is going on and lead them to a deeper understanding of the world around them.

As the first unit in the OpenSciEd program, during the course of this unit, students also develop the foundation for classroom norms for collaboration that will be important across the whole program.