During a recent ride in an elevator, I was startled by an observation. Once the door closed, the features on the back wall of the elevator were evident in a reflection on the door; however, my own reflection appeared absent (see Fig. 1). How could that be? What physics caused this curious phenomenon? The elevator had wooden molding, including horizontal strips that ran all the way around the back and sides (see Fig. 2). These horizontal strips were what showed up most clearly in the reflection. The door's surface was brushed metal with the brush marks all running vertically. Therein lay the solution.
Reference
1.
G. J.
Ward
, “Measuring and modeling anisotropic reflection
,” ACM SIGGRAPH Comp. Graph.
26
, 265
–272
(July 1992
). © 2014 American Association of Physics Teachers.
2014
American Association of Physics Teachers
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