The Knuckleball Dance

MATERIALS NEEDED:

  • graph paper
  • pencils and erasers
  • protractor
  • baseball

STEPS TO FOLLOW:

one Discuss with the class the dynamic that takes place when a knuckleball's flow goes from turbulent to laminar flow because of the stitches on the baseball. Pass around a baseball so that each student can feel the stitches on the ball.

two Emphasize the terms under 'Words to Know' so that the students have an understanding of the words you are using to explain to them the flow of the knuckleball.

three Continue the discussion until everyone has a grasp of the altering state of flow from laminar to turbulent as well. The laminar flow will separate earlier than the turbulent flow.

four Also, using saliva or Vaseline causes the pitch to slide through the fingers and thus have little spin. Therefore, the ball moves like a knuckleball, but at the speeds of a fastball. This makes a spitball next to impossible to hit. (Refer to the Teacher's Text for the information needed for your discussion with the class).

five Pass out graph paper and ask the students to make a Venn Diagram of the overlapping flow from laminar to turbulent that the knuckleball goes through. Have the students use the protractors to make the overlapping circles. Ask the students to label the two parts: laminar and turbulent and the overlapping asymmetry.

six Display the Venn Diagrams on a Bulletin Board in the classroom.


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Last modified: Sat Aug 30 15:52:40 PDT 1997

Copyright © 1997 by Cislunar Aerospace, Inc. All Rights Reserved.