Human Sundial Lesson Plan

1. A sundial is the earliest type of timekeeping device and dates back to about 1500 BCE. It consists of a dial base and a pointer called a "gnomon" which casts a shadow onto the base. The sundial originated in ancient Egypt. Have students look at images of sundials, including examples of the world's oldest known version from Egypt's Valley of the Kings.
2. Have students look at an image of a sundial and identify where the time divisions are placed. (Note that they do not mimic those on a clock's face.) A sundial must be placed on a level surface with the gnomon pointing directly north. The sun will cause the gnomon to cast a shadow onto the time indicator.
3. Bring students outside on a clear sunny day and find a safe, open space. Have students draw a large circle and use a compass to determine and mark where north is. Then have them fill in the numbers per a diagram of a sundial base.
4. Have students take turns being the gnomon by standing in the center of the circle and letting their shadow tell the time.

SCI: Convey designs through sketches, detailed drawings, or physical models to communicate ideas and solutions.

SCI: Design pictorial or graphic representations/models that are useful in communicating ideas.

SCI: Use relative scales that allow objects and events to be compared and described. 

MATH: Elicit evidence of thinking about time as a measurement.

Have students investigate how to read a sundial in different hemispheres or at the equator. Will the gnomon point north in the southern hemisphere? Would it be different at the equator?

Another time-measuring device is the hourglass. Ask students to investigate this apparatus. How is the time determined? What are some of the requirements for the sand in the hourglass? Where might we see a type of hourglass in use today? For example, there are three-minute egg timers and games often use them to time a player's turn.