Education Technology

Stretch It to the Limit: The Linear Force Relation for a Rubber Band

Activity Overview

In this activity, students' will use a force sensor and a motion detector to study the relationship between the force applied to a rubber band and the distance to which it stretches. They will then model force versus strech data with a proportional relationship.

Before the Activity

  • Connect the force sensor to Channel 1 on the CBL 2™ or Vernier LabPro®
  • Connect the motion detector to the DIG/SONIC port of the CBL 2 or the DIG/SONIC 1 port of the LabPro
  • Connect the CBL 2 or LabPro to the calculator using the Unit-to-Unit cable
  • See the attached PDF file for detailed instructions for this activity
  • Print pages 81 - 88 from the attached PDF file for your class

During the Activity

Distribute the pages to your class.

Follow the Activity procedures:

  • Prepare the force sensor and motion detector for data collection
  • Stretch and relax the rubber band
  • Use the force sensor and measure the force of the pull
  • Use the motion detector and record the amount the rubber band is stretched
  • Plot graphs of force versus time and distance versus time
  • Graph force versus distance
  • Plot the line of proportionality with different values for the slope and find the line that provides a good fit for the data
  • Calculate the value of the slope from the equation and compare the values
  • Do a linear regression on all the data points and determine the regression line equation
  • After the Activity

    Students' will fill in the Student Data Collection and Analysis Sheet and answer the questions listed in it.

    Review student results

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