Education Technology

On the Rebound

Published on 06/18/2010

Activity Overview

In this activity, students collect motion data for a bouncing ball using a motion detector. They analyze the data and attempt to find the exponential relationship between the bounce number and maximum height that the bounce reaches.

Before the Activity

  • Connect the computer to the CBL 2™ using the TI connectivity cable

  • Connect CBR 2™ to the DIG/SONIC port of the CBL 2™ unit
  • Open a new TI InterActive!™ document
  • See the attached PDF file for detailed instructions for this activity
  • Print pages 41 - 46 from the attached PDF file for your class
  • During the Activity

    Distribute the pages to the class.

    Follow the Activity procedures:

  • Hold the motion detector 1.5 to 2 meters above the floor
  • Hold a ball 0.5 meter below the detector and drop it
  • Collect distance versus time data and plot a graph
  • Record initial drop height as bounce zero and find the maximum heights of each successive bounce
  • Plot bounce number versus bounce height
  • Observe the graph is exponential in form and can be modeled by the equation y = ab^x
  • Find the value of a - the initial height
  • Find the ratio of maximum height of each bounce in relation to the preceding bounce
  • Record the ratios and find the average ratio which represents b
  • Enter the values of a and b in the equation to find y
  • Observe this equation y = ab^x is a relationship between bounce height and bounce number
  • Use the exponential model to find the height of the ball at the 8th bounce and also the number of bounces the ball makes before it no longer reaches a maximum height of 5 centimeters
  • After the Activity

    Students complete the analysis and answer questions.

    Review student results:

  • As a class, discuss questions that appeared to be more challenging
  • Re-teach concepts as necessary


  • If you use TI-Navigator™, you can download the attached EDC file and use as a quiz to check understanding. If you are using the TI-73, you may need the attached PDF.