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Earth Clock

By The Junior Master Gardener® Program

Garden- and ecology-themed books inspire children through text and imagery to explore the environment around them. Junior Master Gardener (JMG), an innovative 4-H youth gardening program, has created the Literature in the Garden curriculum to enhance children's understanding of the messages and powerful illustrations conveyed in these stories. Through outdoor activities, creative expression and open exploration, children have a hands-on opportunity to explore the natural world and develop leadership skills, personal pride, and a greater sense of responsibility and community involvement.


WeslandiaInspired by the book Weslandia by Paul Fleischman, this Earth Clock activity teaches children how to build a sundial to understand how the sun can help us tell time. Weslandia is the story of an outcast named Wesley who decides to create a new civilization in his backyard over summer vacation. He discovers a new staple crop – the swist – and using his vast imagination, builds Weslandia around it. Wesley invents a new language, games, foods, clothes, a counting system and many other innovations to create his own unique paradise and ultimately triumph over his foes. Among Wesley's creations is a sundial made from a flower stalk.

Objective: Build a sundial to understand how the sun can help us tell time - This activity is best done with the help of an adult and a few friends.


  • 4- to 5- foot pole (a broom handle works well)
  • trowel or shovel
  • hammer or mallet
  • several softball-sized rocks (these can be found in the area or donated from a local landscape supplier)
  • acrylic paint
  • brushes
  • wristwatch
  • directional compass
  • map or globe with latitude marks or computer access to the internet
  • protractor

In Weslandia, Wesley used a new kind of sundial that used the “movement of the sun” across the sky to create a shadow that would tell the time. With a sundial, you can make a clock that will never need batteries!

Follow the steps below to make an Earthwork sundial :

  1. Using the globe, identify the latitude of your location. You may also use a map or visit the resource links at

    Rocks in Circle
  2. Go outdoors on a sunny day and form a circle 10 feet across on level ground. Place the rocks in 12 locations around the circle.

  3. Using the compass, locate north. The dial of the sundial with point towards the north.

  4. Dig a hole for the pole at the center of the circle 12 inches into the ground.

  5. Place the pole in the ground and make the angle match your latitude. To introduce the concept of angles and degrees of angles, have the students point to one horizon and slowly sweep across the sky until they are pointing straight up. Tell the students that when they are pointing straight across at the horizon, it is not toward the sky at all, so the angle is considered 0 degrees. When they are pointing straight up at the sky, that is 90 degrees.

  6. Once the pole is in the hole you’ve made, support it with the loosened dirt. Piling rocks around the pole’s base will help hold it at the correct angle.

  7. “True up” your circle: Once the pole is in position, form a circle small enough that a shadow from the pole crosses the circle. Using a rope, make all of the rocks equally distant from the center.

  8. Go back inside and watch the clock. A few moments before each hour, return to the sun circle. When “the clock strikes,” reposition a stone where the shadow of the pointer pole crosses the circle and paint the number of that hour on the stone. Continue as long as possible or until all the daylight hours are marked. You will periodically need to reset the Earth Clock for standard time and daylight saving time. For more information about sundials or how to make a tabletop sundial, visit the resource links at

The secret to making the sundial work is to place the sloping stick, called the style, in the ground at the same angle of degrees as the latitude of where they are. Recall the latitude you found and then point up at the angle that matches that number. Using an instrument called a protractor, you can measure exactly what that correct angle would be.

From all of this comes Wesley’s and our ability to create a clock that can use the Earth’s movement and shadows to tell the time of day!


To learn more about Junior Master Gardener Groups in your area, or how to start your own, visit the JMG web site at:

All text and images Copyright © 2005 by the Texas Cooperative Extension. All Rights Reserved.


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