- Sturdy cardboard
- Mat knife
- Clay (optional)
- Stick or dowel
Objectives: Children will discover that the position of the sun can help them tell time.
To Prepare: Use the mat knife to cut a large circle out of sturdy cardboard. Glue the empty spool to the center of the circle. Find a stick on the playground.
1 On a bright, sunny day, read a book about the differences between night and day, such as one of those listed below. Talk with children about the things they do when the sun rises (wake up), is high in the sky (play), goes down (eat dinner), and so on. Then explain that they are going to use the sun to tell what time it is.
2 Take the materials you prepared outdoors. Find a level spot that receives bright sunlight all day long. Help children assemble the sundial by placing a stick firmly in the spool. If needed, place some clay at the base of the stick to help keep it sturdy.
3 Ask children what they see when the sun shines on the stick. Use the marker to indicate where north is (that will be noon). Mark where the stick's shadow falls. Check the time and, if necessary, turn the sundial until the shadow falls in the correct place. Explain to children that it will move as time passes.
4 Throughout the day, have children notice where the stick's shadow falls on the cardboard circle. Point out the sun's position in the sky. Mark the shadow's position every hour. After a few hours, talk about the pattern of marks on the sundial. What does it look like?
Tip: Cover the sundial with a wastebasket overnight to keep it dry.
- Invite children to use the sundial whenever they're outside. What happens on a cloudy day? If the sun does not shine, is there a shadow? Can children still tell time with the sundial? If you like, use a flashlight to simulate the sun and create shadows.
- Display a variety of instruments that tell time, such as an hourglass, egg timer, windup kitchen timer, windup alarm clock, battery-operated watch, digital watch, and so on. Invite children to compare and contrast the items.
Read about what happens when the sun rises and sets
Wake Up and Goodnight by Charlotte Zolotow
What Makes a Shadow? by Clyde Bulla
What the Sun Sees, What the Moon Sees by Nancy Tafuri