Gnomon facts for kids
The gnomon is the part of a sundial which casts the shadow. Gnomon is an ancient Greek word meaning "indicator", "one who discerns," or "that which reveals." In the northern hemisphere, the shadow-casting edge is normally oriented so that it points north and is parallel to the rotation axis of the Earth. That is, it is inclined to the horizontal at an angle that equals the latitude of the sundial's location. On some sundials, the gnomon is vertical. These were usually used in former times for observing the altitude of the sun, especially when on the meridian. The style is the part of the gnomon that casts the shadow. This can change as the sun moves. For example, the upper west edge of the gnomon might be the style in the morning and the upper east edge might be the style in the afternoon.
The art of constructing a gnomon sundial is sometimes termed gnomonics.
Anaximander is credited to introduce this Babylonian instrument to the Greeks.
Images for kids
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invariant snail in the subtraction of gnomons (Hero's definition)
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The gnomon projection on the floor of the Santa Maria del Fiore Cathedral during the solstice on 21 June 2012
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Gnomon situated on the wall of a building facing Tiradentes Square, Curitiba, Brazil
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A gnomon in computer graphics
See also
In Spanish: Gnomon para niños
