Title of Lab: Fiber Analysis Purpose(s) of Lab: A victim of an assault case was able to tear a piece of cloth of the shirt of the attacker. Three individuals matching the victims description have been located in the immediate area and all of them had torn shirts. Your job is to learn how to compare textiles based on physical characteristics and identify the type of fiber based on microscopic examination. Pre-Lab: Familiarize yourself with the following: Common weave patterns:

Types of natural and synthetic fibers:

Materials: Go to: http://school.cengage.com/forensicscience/# Procedure: 1. 2. 3. 4. Open the site listed above. Click on launchthis will open a new window. Select Chapter 4. Click on Interactivity in the right hand corner.

5. Simply follow the directions to complete the table and answer the questions. Data: Sample What is the horizontal thread count? What is the vertical thread count? Type of Weave Pattern

Crime Scene Suspect 1 Suspect 2 Suspect 3 Further examination of the fabric included scanning electron microscopy of the textiles. Identify the type of fibers found at the crime scene and on each suspect. Crime scene Type of Fiber

Type of Fiber

Suspect 1 Type of Fiber

Suspect 2

Suspect 3

Type of Fiber

Conclusion: Which suspect assaulted the victim? Questions: 1. Which observation was the most helpful, thread count, weave pattern, or SEM? Explain why. 2. Of the 6 types of fibers you observed in the pre-lab, which are natural and which are man-made? . 3. Of the natural fibers listed in the pre-lab, which might have a medulla? Why?

Enhanced and adapted from source: http://school.cengage.com/forensicscience/#