PURPOSE: To illustrate light rays for spherical aberration.
DESCRIPTION: Rays emanating from a single point object but with different divergence are illustrated as they go through a spherical lens. Those rays further from the optic axis are focused closer to the lens, because the spherical lens has too much curvature at larger angles. The model shows proportional displacements but is not to scale, and aberrations are exaggerated.
REFERENCES: (PIRA unknown.) See Demonstration Reference File for information about this model.
EQUIPMENT: String model, as photographed.
SETUP TIME: None.
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