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Penumbra by Christopher Martin Olson

1st Place - Contrived Category

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School: Sacramento Waldorf School

Teacher: John Millard

This photo demonstrates two simple concepts about shadows. Firstly, objects closer to a light source block more of the light, creating a larger shadow, and an object farther away blocks less light and casts a smaller shadow. However, if the closer object is smaller than the object farther away, they will cast shadows of similar size, as seen in the image. In addition, objects closer to a non-point light source cast more of a penumbra, the fuzzy edge of the shadow seen most clearly around the P, E, and N. The umbra is the part of the shadow where all light is blocked, but the penumbra is where light from one part of the light source is blocked but light from another part shines past. When an object is closer to its shadow and farther from the light, (the A for example), light rays are more parallel and very little penumbra is created because the light source is completely blocked. Moving letter by letter towards the P, however, rays of light are farther from parallel when they pass the object, and more and more light is only partially blocked, creating the blurry penumbra.

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