Activity 2: A Tool for Inquiry
CBL Motion Detector

What can I expect to get out of doing this activity?

The Calculator-Based Laboratory system and the ultrasonic motion detector as a sensor provides you with a unique opportunity to observe the graphing of motion while it is happening.

You will explore the results on a real-time distance-time graph while walking at different speeds and directions.

In this activity you will explore the capacity of the CBL system to visualize:

  • real-time motion data collection,
  • the rationale for teaching with a CBL,
  • using the motion detector as a research tool.
  • We assume you got the CBL and Sonic Ranger to work!!
    If you did, great. If you didn't?? What do you do?

    As we stated the CBL can be picky. We are going VERY slowly through this technical setup. If you still have difficulties please call the Texas Instruments CBL HOTLINE (1-800-TICARES).
    In this activity we are going to extend only slightly the capacity of the CBL interface. There is plenty of time to work with the CBL. The goal of this second activity is simple:
    • use the MOTIONRT program to analyze motion of people walking to and away from the Sonic Ranger,
    • build graphical interpretation skills using real-time data collection.
    how long will it take? 60 minutes for continued work with the CBL system.

    There is no reading assignment for this activity. If you wish you can read more about MOTIONRT in Exploring Physics and Math with the CBL System. WARNING: this material is in Activity 2: (pages 17-19) displacement plots, but the book calls the program DISTANCERT, not MOTIONRT.
    Activity 2
    TO DO Checklist

    __ Print this page!

    Readings & Hands On
    __ Complete the hands on assignment.

    Initial Thoughts
    __ Post your initial comments on Activity 2 and read some of the module-based discussion in the CBL Discussion area.

    Local Study Group Meeting
    __ Attend LSG meeting where colleagues share their new "tools" for inquiry.

    Further Reflection
    __ Visit the CBL Discussion area again to read more of the dialogue and share your insights and questions.

    Download the MOTIONRT program from the disk with TI-Graph Link. Experiment with the Sonic Ranger and the MOTIONRT program.


    1. Design some experiments like walking slowly towards the Sonic Ranger then away. Or walk quickly then stop and return. What would the graph look like? What does it look like when you use the CBL?
    2. What is the physical representation of a negative slope by MOTIONRT ?
    3. What is the meaning of "quickly," "slowly" and "stop" in the graph made by the MOTIONRT and Sonic Ranger?


    • If you run into technical problems, visit our handy Troubleshooting Guide with visuals for a quick solution or the Texas Instruments CBL Frequently Asked Questions (FAQ) page.
    • Mounting the motion detector on a ring stand gives stable readings.
    • Once you open MOTIONRT remember to select MANUAL SCALE from the SCALE OPTIONS menu. You may have to adjust the scale for different experiments.
    • The Sonic Ranger is inaccurate at distances of less than 50 cm.
    • Better readings are made if a person carries a large flat surface like a poster board.