# CBL Unit Day #2

### Equipment Required

• CBL unit
• TI-82, TI-83, or TI-85 overhead graphics calculator with a unit-to-unit link cable
• motion detector
• TI-82/83 view screen
• overhead transparenies cut to fit over view screen with curves sketched on them in colored marker

### Program Listing

This experiment requires that you download or enter the HIKER program into your TI-82, TI-83, or TI-85 calculator.

### Equipment Setup Procedures

To connect the equipment:

1. Connect the CBL unit to the TI-82 calculator with the unit-to-unit link cable using the I/O ports located on the bottom edge of each unit. Press the cable ends in firmly.

2. Connect the motion detector to the CBL using the sonic port.

3. Connect the overhead calculator to the view screen, place the view screen on an overhead projector. Turn on overhead.

4. Secure the motion detector so that it is flat on a table top and perpendicular to the line of motion of the walker.

5. Turn on the CBL unit and the calculator.

### Experiment Procedure and Analysis

1. Select one of the overhead sheets and place it on the view screen. Tell a student that he/she should try to walk so that the curve that represents his/her distance versus time traces the graph that was drawn on the overhead sheet.

2. Run the program HIKER on the TI-82. It will instruct the user to "PRESS ENTER TO START GRAPH." When the CBL is collecting data a clicking noise will be heard. The TI-82 will graph the distance versus time as the student walks.

3. Let the student make one attempt to walk the curve without help from the rest of the class. After the student tries, the class should discuss some of the curve's features. Possible questions for discussion could include why is there a max or a min at a certain point on the graph? What is the walker doing when the curve is decreasing or increasing?

4. Select a second student to walk and a second curve for him/her to try to copy. Follow steps 1-3 above again.

5. The class should analyze the graph. Where does the graph show that the rate was fastest, what is the slope in that area? Where does the graph show that the rate was slowest, what is the slope in that area?

### Extend (student activities)

1. Have a partner sketch a curve. Write an explanation about how one could "walk this curve."

2. Describe how a person might "walk a curve" that is increasing constantly. Describe the velocity needed to accomplish this goal.

3. Describe how a person might "walk a curve" that is decreasing constantly. Describe the velocity needed to accomplish this goal.

4. Describe how a person might "walk a curve" that is horizontal line. Describe the velocity needed to accomplish this goal.

5. What is the connection between velocity and behavior of the distance function.

Go on to DAY3!!