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01 Shadow Dance

About this Activity
The purpose of this activity is to experiment with shadows and light sources and to understand the relationship between the angle of illumination and the shadow's length.

 
Shadow photo
Late afternoon sunshine casts long shadows on desert monoliths.

 What You'll Need
1 - tube of glue or roll of tape

1 - large piece of posterboard

1 - small piece of cardboard or Styrofoam

1 - toothpick

1 - flashlight

 

 

 

 

 

 

 

 

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Let Us Know 
How did this activity work for your family?
Email us at:

outreach@ssl.berkeley.edu

 


What to Do
Cut a small rectangular piece out of the cardboard or Styrofoam, approximately 3/4 of an inch wide (2 centimeters), 4 inches (10 centimeters) long. Next, push a toothpick into the center of the small cardboard or Styrofoam piece. Put this piece on top of a larger piece of cardboard or posterboard.

Shine your flashlight on the toothpick to create a shadow line. Try different ways of making the shadow line change its direction and its length.

E X P E R I M E N T     1

Moving the Flashlight
1 Without moving the toothpick, make the direction of the shadow line change by moving the flashlight.
  illustration

 

E X P E R I M E N T     2
Moving the Toothpick

1 Without moving the flashlight, but keeping it pointed at the toothpick, move the toothpick around and observe what happens to the shadow.
  illustration

 

E X P E R I M E N T     3
Using the Sun as the Light Source

1 You can also form a shadow line by placing a toothpick in direct sunlight. This can be done by going outside or to a window that faces the Sun. What happens to the shadow when you move the toothpick around in the sunlight? How is it similar or different to the shadow created by the flashlight?
  illustration


What's Going On
You should notice some interesting differences between shadows created by the flashlight and those created by the Sun. Because the Sun is so far away, you may have noticed that the angle of the shadow remained the same when you moved the toothpick. Since the light source of the flashlight was much closer, the shadow behaved differently.

Related Websites

Bob Miller's Light Walk
www.exploratorium.edu/light_walk


 
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