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Activity

Sundial

Summary: 
Assemble a simple sundial, and watch its shadow move over the course of a lesson.
Science content (2016 curriculum): 
Earth/Space: Weather, Seasons, Climate Change (K, 1, 4, 7)
Earth/Space: Sun, Moon, Solar System, Universe (1, 4, 6)
Science topic (2005 curriculum connection): 
Earth and Space Science: Surroundings (grade K)
Earth and Space Science: Daily and Seasonal Changes (grade 1)
Earth and Space Science: Stars and Planets (grade 3)
Earth and Space Science: Weather (grade 4)
Physical Science: Light and Sound (grade 4)
Lessons activity is in: 
Materials: 
  • clear sunny day
  • long stick
  • bottle or container that will hold the stick upright
  • playground and chalk, or other surface and writing implement
Procedure: 

Find an open area that shadows will not pass over during the course of the lesson, and that will not be disturbed by other students.
Set the stick upright in the bottle.
Draw a line along the shadow of the stick and mark the time at the end of it.

Every 30 mins, draw in the new position of the stick's shadow.
Once they get a sense of how far it will move, students can be asked to start predicting where the shadow may fall after a certain amount of time. (No point in asking them to predict before they have some sense, as it will be wild guesses, making them feel successful or not for no reason.)

Observe how the shadow moves over time (it is surprisingly fast).

As the earth rotates the position of the sun in the sky changes, so the shadow rotates around the stick.
Hence the position of the shadow can tell us how much time has passed, therefore the time.
Over the next day or so, the time can be predicted from the position of the shadow.

The length of the shadow depends on how high the sun is in the sky, and will change with the time of day and the seasons.

Note: this simple sundial with an upright stick will not work for telling the time over the course of the year. Precise sundials are at an angle, and have more complex readings for measuring time.

Grades tested: 
Gr 2
Gr 3
Teacher: 
Ingrid
Teaching site: 
General Gordon Elementary Science Club
Activity originally developed and delivered: 

Gordon Elementary Science Club