Education Technology

Swinging Ellipses: Plotting an Ellipse

Published on 07/02/2009

Activity Overview

In this activity, students will use a motion detector to record the position and velocity of a swinging pendulum. They will plot the data as a velocity versus position phase plot and determine an ellipse that fits it.

Before the Activity

  • Connect the motion detector to 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
  • Download Vernier EasyData™ application using the TI Connect™ software
  • See the attached PDF file for detailed instructions for this activity
  • Print pages 22-1 thru 22-5 from the attached Student Edition PDF file for your class
  • Print pages 22-1T thru 22-3T of the Teacher Edition
  • During the Activity

    Distribute the pages to your class.

    Follow the Activity procedures:

  • Connect the pendulum bob to an 80 cm long string and suspend it from a support
  • Arrange the Motion detector so that the bob swings back and forth in front of it and comes no closer than 50 cm.
  • Examine the distance versus time and the velocity versus distance plots on the calculator
  • Trace the velocity versus distance graph and record the average of the absolute values of both the x and the y intercepts in the Data Sheet
  • Graph the ellipse equation
  • After the Activity

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

    Review student results

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