Like people thousands of years ago, you can tell time and direction and follow changes in the seasons by keeping track of the sun's motion with a sundial. The gnomom (pronounced NO-mon) is the most important part of a sundial. The shadow cast by a gnomom indicates the sun's position in the sky at various intervals throughout the day, month, and year. Sometime, as in this activity, the gnomom is simply a vertical stick; other times it's an angled piece of stone or wood.
You will need
What to do
Try to get started early in the morning, shortly after the sun rises. Find a level location outdoors that will not be disturbed and that will stay out of the shade of trees and buildings all day. Stick the pencil into the lump of clay to form your gnomon, and place it on top of the paper, and place the paper and the gnomon on the ground. Hold the paper down with rocks. Be sure the pencil is as straight up and down as you can make it.
Trace the shadow of the pencil throughout the day -- at least every hour -- and write down the time at the tip of each shadow. Continue making observations until as late in the afternoon as you can. At the end of the day, draw a curved line through the tips of all the shadows.
To Observe and Notice
As the Sun moves across the sky from east to west, you'll notice the shadows on your sundial move from west to east. And in most places in the northern hemisphere, the shortest shadow occurs when the Sun is due south. Use this information to mark the points of the compass on your sundial.
Once you've made your sundial, you can use it the very next day to tell the time without a watch. But if you use it day after day, month after month, you'll begin to notice that the path of the Sun changes with the seasons. In the summer, the midday shadows will be shorter than in the winter. The exact directions of sunrise and sunset also change from due east and west to slightly north or south of east and west.
Going Further
Because it takes a little patience to notice the seasonal shifting of the Sun, try this: Record the date on your new sundial and store it away in a safe place. Write a reminder in your calendar on a date 6 weeks from now and 12 weeks from now to "get out the sundial." When that date comes, dig out your sundial and place it in the same location, aligning north, south, east and west. Keep track of the gnomon's shadow with a different colored pencil, and notice the difference. Is the noontime Sun higher or lower in the sky than when you last checked?
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