After This Lesson, Students Will Be Able To

Fiber Analysis

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OVERVIEW

Participants will learn about the different types of fibers and how each of them burn in different ways.

OBJECTIVES

After this lesson, students will be able to:

Learn the different types of fiber analysis

Identify the different types of fibers.

Analyze how different types of fiber burn

MATERIALS

· Fiber Samples

· Watch Glass

· Forceps

· Wooden Splints

· Matches

PROCEDURES

Activity 1 Fiber Flame Test

1. Hold a small piece of a fabric sample in the forceps

2. Use a match to light one of the wooden splints.

3. Over the watch glass, bring the fabric near the flame – note what happens. Does it ignite immediately, curl in the heat, or shrink away from the flame and melt?

4. Place the fabric in the flame and note whether it burn slowly or quickly and whether it melts and drips.

5. Remove the fabric from the flame - does it continue to glow or burn, or is the flame extinguished.

6. What does the burning fiber smell like? Burning paper? Burning hair? A chemical smell?

7. What is left over after the fiber is burned? Does it form a hard bead of residue, or did it leave ash behind? Is the residue brittle?

8. For each sample, fill in the following chart, the transfer to the case file.

BACKGROUND

Fiber Analysis is a method used by law enforcement to identify and examine a type of fiber to produce evidence from a crime scene. Fiber can be transferred when a person has a close contact with the victim or suspect. Fiber transfers can also happen during break-ins when the suspect gets caught on a broken glass or chipped wood. Typical tests used to identify different fibers are visual observations and flame tests where fiber samples are burned and observations regarding smell, appearance and ash remains are recorded.

References

Home Science Tools: Crime Scene Science Kit, www.homesciencetools.com

http://en.wikipedia.org/wiki/Fiber_analysis