Study Questions • Discussion Topics
Activity 1: Chart the Sun
Activity 2: Build a Sundial
Chart the Motions of the Sun
The Egyptians understood the rhythms of the sky, especially the motion of the Sun, by long-term, careful observation. Students can also watch the motion of the Sun over the course of a semester. Find a place with an unobstructed view of the western sky, but with some landmarks (telephone poles, tall buildings) on the horizon. The place should also be safe to visit at sunset.
Sketch or photograph the horizon, with the landmarks. You may want to make several photocopies of this illustration, and mark the exact place where you stood. You may also want to use a compass to note where due east is. Watch the Sun set every few days for several months from that spot. Each time, draw the Sun on a horizon diagram, making careful note of the Sun's location compared to the landmarks. You may draw on the same diagram, or use multiple diagrams to make an animated "flip chart."
It is even possible to make some numerical measurements, by exploiting the fact that a fist held out at arm's length is about 10 degrees across. You can measure how far (in degrees) the sunset point is from a variety of landmarks, and make a more accurate drawing. If you do this, however, make sure to stand on exactly the same spot every time!
Notice how the sunset spot moves over the months. What direction does it move? How many degrees does it move each week? Does the Sun speed up or slow down? Does it ever stop? How many degrees away from due east does the Sun travel before it "turns around?" Is there anything special about the day the Sun turns around? What about the day it travels fastest? It will take a full year to go through a complete pattern.
Naturally, you can use sunrises instead of sunsets. If you have the use of a field or similar open space, you may want to create a "circle" of stones or flags indicating where the Sun rises on certain days. You can make your own Stonehenge or Nabta!