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How Do Stars Twinkle?
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Science Area:  Astronomy
Content:  Stars

Twinkle Twinkle Little Star

 

Materials:

Laser

Hot Plate

White Wall

 

Procedure:

Start by shining laser on the wall and observe that the light from the laser is not moving.  Next, turn hot plate on high and let it heat up for 5 minutes.  Then, place the laser directly behind the hot plate and shine the laser light on to the same wall and observe that the light appears to be moving or “twinkling”

 

 

Questions: 

Why does the light appear to be moving?

What is the purpose of the hot plate in this demonstration?

 

Explanation:

 

The heat from the hot plate is disturbing the air above it.  As the light passes through the air above the hot plate, the light gets bounced around by the air molecules.  This is the same reason that stars appear to twinkle.  The light from the stars has to pass through the disturbances of our atmosphere.  As a result the stars in the sky appear to twinkle just as the laser light does in this demonstration. 

 

 

Source:  Personal interview with James Aikens.  Astronomy teacher at William Fremd High School in Palatine, Illinois.   May 29, 2007.