Education Technology

# Activities

• ##### Subject Area

• Math: Algebra I: Linear Functions
• Math: Algebra I: Piecewise Functions
• Science: Physics: Kinematics

6-8
9-12

• ##### Activity Time

50-60 Minutes

• ##### Device
• TI-83 Plus Family
• TI-84 Plus
• TI-84 Plus Silver Edition
• TI-Navigator™

CBR™/CBR 2™

• ##### Other Materials
• Meter stick/measuring tape
• Duct tape
• Poster board

## Crime Scene Investigation - Stride Pattern Analysis with CBR 2

#### Activity Overview

By using the Calculator-Based Ranger (CBR2™), students can plot the distance-time graph of a walking or running person. Students find correlation between the stride distance, velocity, and the height of a person, walking or running at a steady pace and compare that to the stride pattern left at the scene. From this comparison, students can determine which suspects stride most closely matches the strides left at the crime scene.

#### Before the Activity

Students analyze stride pattern left at the "crime scene" and measure stride distance(s).

#### During the Activity

Students walk or run fixed number of strides at a steady pace and determine average stride distance and velocity of each person in the group. They record the height, average stride of each person, and velocity in the calculator lists. Using TI-Navigator™ this data is shared by all students for analysis.

#### After the Activity

Discussion Questions:

What is the relationship between walking/running speed and average stride distance?

What is the relationship between persons height and stride distance during walking? During running?

Can you determine mathematical model of this relationship? Based on the analysis of the experiment, can you determine the height of the perpetrator and if he/she was running or walking?