Education Technology

# Activities

• ##### Subject Area

• Math: Statistics: Inferential Statistics
• Science: Forensics: Crime scene evidence

9-12

• ##### Device
• TI-83 Plus Family
• TI-84 Plus
• TI-84 Plus Silver Edition
• TI-84 Plus C Silver Edition
• TI-84 Plus CE
• ##### Other Materials
This is Activity 10 from the EXPLORATIONS Book:
Forensics: Connecting Science Investigations with TI Data Collection Activities.

The following materials are required for this activity:
• Newspaper
• 13 pieces of white paper
• Disposable pipettes or droppers
• Simulated blood
• Calipers, or compass and metric ruler
• Meter stick

## Forensics Case 10 - Dropped at the Scene: Blood spatter analysis

#### Activity Overview

In this activity, students graph data to find quantitative relationships and create a standard reference curve for comparison with unknown data. They analyze blood spatters and examine r2 values for linear, natural logarithm, quadratic, and power curve fit. They find the curve that best fits the data and use it to determine the height from which blood has dropped.

#### Key Steps

• Students create a reference curve by measuring the diameter of "blood" drops from various heights. Then the coefficient of determination (r-squared) and the graphs of four regressions are compared to pick the best model to use to determine the possible height of the suspect.