Document Type
Other
Publication Date
2026
Abstract
Prior to mechanical clocks or electronic clocks, ancient peoples used Gnomons or Sun Dials to keep track of time (Li, 2017). As the sun moved from sunrise to sunset, shadows would trace out the path of the sun, yet in the opposite direction. It is interesting to note that when the sun is lower in the sky, that is on the horizon, the shadows are longer. For example, at dawn, when the sun was in the east, a tree or rock would have a long shadow pointing west. To make the measurements more consistent, people would place a stick in the ground, on a wall, or on a pedestal and record where the shadow was, thus making a sundial.
Supplemental files include two demonstration videos. (.mp4)
Publisher
South Dakota State University
Recommended Citation
Browning, Larry and Cutler, Kay, "Gnomon (Sun Dial)" (2026). Astronomy Activites. 5.
https://openprairie.sdstate.edu/recee-astronomy/5