The trouble with light
	• Physicists ideas about light are difficult to teach to novices for two reasons. – Sighted people have lots of experience with light. As a result, they have strong associations and interpretations that create barriers to learning. – Physicists’ use a variety of models (rays, waves, photons), sometimes hybridizing them in ways that are difficult for students to make sense of. • There has been a lot of PER concerning learning about light at a variety of levels.