Education

In this activity, students will learn how the sun was used before traditional clocks to tell time:

The ancient Egyptians made the earliest known sundial in about 3500 bc. This sundial was simply a stick or a pillar that cast a shadow on the ground. The ancient Greeks made a sundial with a bowl-shaped opening cut into a block of stone or wood. A pointer in the center cast shadows inside the bowl. Muslims later invented the modern sundial—the type with the angled gnomon. Clocks began to replace sundials in the 1300s.

Materials:

• Paper plate
• Plastic straw
• Sharp pencil
• Crayons
• Duct tape
• Sunny place
• Clock or watch

Instructions:

1.  Poke a hole in the center of a paper plate with a sharp pencil so the straw will go through.

2.  Turn the paper plate upside down. Write the number "12" on the edge of the paper plate.

3.  Use a ruler and draw a line from the 12 to the hole in the paper plate.

4.  Put the Straw in the hole and take the paper plate outside just before noon. Put it on the ground and slightly tilt the straw towards the line and 12 you drew.

5.  At exactly noon, turn the paper plate so the straw's shadow lines up with the line and the 12.

6.  Fasten the paper plate to the ground with duct tape or something else so it doesn't move. Have the kids predict what will happen an hour later.

7.  At exactly 1:00, mark the spot on the paper plate and write 1. Repeat this process every hour on the hour to make the clock.

8.  To use the sundial on subsequent days, it must be put in the same place in the same position.