Rudy Keil                      Schurz High School
                               3601 N. Milwaukee Ave.
                               Chicago, IL 60641

    1.To build a persistence of vision model of flying birds.
    2.To relate this model to persistence of vision in viewing movies.
    1. Assorted short strips of movie film.
    2. Two slotted circles duplicated on stiff paper.
    3. One set of eight birds in various positions of flight. 
    4. One blunt pencil, four strips of masking tape,one sharp scissors.

    Give each student a strip of movie film and have students observe the
individual frames.
    Distribute materials for the flying birds model. Have students cut two slotted 
circles and eight slotted bird pictures. Wrap a few turns of masking tape near the 
blunt end of a pencil. Place one of the circles over the blunt end of the pencil 
and secure with tape. 
    Slide the top of bird picture #1 into one of the slots in the circle. Tape the 
second circle to the pencil so that the lower slot of #1 bird fits into a slot in 
the second lower circle. Insert birds #2 to #8. 
    Have your students rotate the flying birds. Ask them to explain why the birds 
appear to fly. 
    Refer to the strip of movie film again. Have your students relate the 
persistence of vision phenomena of the flying birds model to the movement caused 
by changing frames of film in a movie.         

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