This is a picture of two red laser beams projected towards two facets of a crystal sphere. Fog (produced by a fog machine) is spread into the path of the lasers to make them visible. Glass, with a refractive index of 1.52, disperses the single rays into multiple rays in different directions; this is caused by reflection off the surface,refraction at the surface, and total internal reflection within the glass. Total internal reflection occurs when the laser beam within the glass strikes the glass/air boundary at angles of incidence greater than 41.1 . This angle is called the critical angle. The many facets of the sphere contribute to the multiple reflected and refracted laser beams. The picture was entitled ‘Ray Play’ because of the photographer’s fascination with laser rays.

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Stephen Chan
St. Elizabeth Catholic High School, Richmond Hill, Ontario
3rd Prize ( HS Individual Category )

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