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Lesson Plans > Science > Grades 9 - 12 > Exploring the Circular Motion of a Tennis Ball
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Kinesthetic Learner
Kinesthetic Learner
Visual Learner
Visual Learner
Auditory Learner
Auditory Learner
Technology Integration
Technology Integration

Exploring the Circular Motion of a Tennis Ball

Understand circular motion, centripetal force, and the law of inertia

 

Grade Level: 9-12

Concept: understand circular motion, centripetal force, and the law of inertia

 
Estimated Duration: 40 minutes
 
Objectives
Students will be able to:
  • provide examples of the law of inertia
  • explain the forces that act on an object during circular motion
  • apply the concepts of inertia and centripetal force to predict that path of an object
Materials
White board
Tennis balls attached to a string
Large, open field
 
Differentiation Strategies
These strategies are used to meet the varied needs of all learners:
  • for various grade levelsVarying academic levels: uses heterogeneous groups to work in an unstructured environment to observe the path of a ball, uses small- and whole-group discussions to ensure all students participate,
  • for visual learnersVisual learners: incorporates diagrams showing the forces applied to an object in circular motion and the path of a ball released after it is swung in a circle
  • for auditory learnersAuditory learners: includes discussion of the law of inertia and the path of a ball
  • for kinesthetic learnersKinesthetic learners: engages students in observing the path of a ball that is swung in a circle once it is released
Key Vocabulary
circular motion
inertia
centripetal force
 
Procedures
Warm Up
  • for visual learners On a white board, write the definition of Newton’s first law, the law of inertia.
  • for auditory learners Ask students to describe experiments, demonstrations, or real-life situations.  For example, they could describe what occurs when a car suddenly stops.  Passengers move forward until their seat belts exert a force stopping their forward motion.  
  • Ask students to discuss with a partner what would happend in a world in which Newton's first law did not apply.  Next, ask them to share an example of one event that could happen.
  • If available, show students a short clip from a horror or science-fiction film, such as Poltergeist, in which objects stop or start moving without the application of force.
Direct Instruction
  • for auditory learners Ask students to come up with examples of objects that move in circles.  Examples could include cars in traffic circles and amusement park rides.
  • Ask students to explain how it is possible that an object can move in a circle, given the law of inertia.
  • Tell students that circular motion results from two motions taking place at the same time: one resulting from inertia and the other from a force pulling or pushing the object toward the center.
  • for visual learners Draw a picture of a circle showing each type of force with arrows as it is applied to one point along the circle.
  • for visual learnersfor auditory learners Explain that the force pulling or pushing the object toward the center is called a centripetal force. Write and define this term on the board.
  • Tell the students that centripetal comes from the Latin words centrum, center, and petere, tend towards, emphasizing that this term only describes the direction of the force and is not a distinct type of force.
  • for kinesthetic learners Demonstrate circular motion by swinging a ball tied to a string. Explain that your hand is exerting a centripetal force on the ball, pulling it toward the center.
  • Ask students to predict the motion of the ball (its path or direction) if you let go of the string.
  • In their journals or on a piece of paper, ask students to draw their prediction.
Practice
  • for various grade levels Divide the class into small groups, pairing students who do well in unstructured environments with those who are challenged in unstructured environments.
  • Take the class outside to a large, flat, clear area. Separate the groups so that they are as far as possible from one another.
  • for kinesthetic learners Have students take turns swinging the tennis ball slowly in a circle and releasing it while the other student watch the path of the ball from a distance.
Assessment
  • for auditory learners Return to the classroom and ask the groups to discuss and draw the path of ball once released.
  • for visual learners Have each group draw the path they observed on the white board and describe the path in every day language.
Closure
  • for auditory learners Explain to students that once the ball is released, their hand was no longer applying a centripetal force on the ball, so that the only force working on the ball was inertia. The ball, therefore, continued in a straight line from the point at which it was released.
  • for visual learners Write and define tangent on the white board. Explain that the ball’s direction was tangent to the point on the circle at which it was released.
  • Applied learning: Ask students how they have experience centripetal forces, in a car turning or in an amusement park ride. Emphasize that although they may feel as if there is a force pushing them outward away from the center of the circle, so that they lean to the right when turning left, it is in fact the law of inertia that is acting on them.
 
Comments (1)
name wrote at Dec 7, 2007 9:34 pm:
what a nice
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