On Day 19 we studied reflection and refraction. Students used light sticks, mirrors, and acrylic blocks to investigate, both qualitatively and quantitatively, the optical behavior of light at the interface of material with different indices of refraction. Their investigations led us to the law of reflection and Snell’s law.*

We introduced a number of new concepts:

• index of refraction
• normal to the surface
• angle of incidence
• angle of reflection
• angle of refraction/transmitted angle

*The photgraphs taken by and used with the permission of Andrew Hart of Hampshire College.