Sunset Calendar

What You Need:

• 11" x 17" piece of white paper
• Pencil
• Clear view of the western horizon (where the sun sets)
• Compass
• Watch

What You Do:

1. On the first day of your observation, watch the sun set and draw the horizon landmarks at the bottom of the page. The horizon landmarks would be things like trees, houses, streetlights and the horizon itself. For instance, if the horizon is hilly, you would draw that. Hold your pencil out at arm's length to help you estimate the distances between things.
2. Use the compass to mark west, northwest and southwest on the page.
3. Note on the horizon picture where the sun sets. Draw a small sun, and write the date and time inside it.
4. A week later, watch the sun set from the same location. Mark the spot with the date and time on the horizon drawing you made.
5. Continue observing the sunset once a week for as long as possible. Add extensions to your piece of paper if you have to.
6. Look at your horizon calendar and guess where the sun will set in three days, three months and six months. Mark these spots on your calendar.
7. Test your guesses on the days you marked by going outside and watching where the sun sets. Did it set where you thought it would?
8. Figure out what time of year it is when the sun sets at the farthest point on the left side of your paper. What time of year is it when it sets on the right side of your paper? Does the sun seem to move faster through the sky during some parts of the year?

What Just Happened?

You just observed a phenomenon that people have been observing all over the world for a very long time. Many ancient cultures made horizon calendars so they could tell what season it was and which one was coming next. They used the calendar to tell them when to plant food, when to move to new camps and when to hold religious festivals.