Hair Analysis

Physical Evidence- Hair Analysis

Goal: To learn how to collect evidence, and analyze them.

Objective:

Presume a link between a crime and its victim or between a crime and its perpetrator.

Distinguish between cloth fibers, animal hair, human hair samples physically, chemically, and biologically.

Use similarities and differences in collected samples for identification.

Equipment:

Long rectangular cover slips
Slides
Light Microscope
Hair Sample (Carolina WW-69-9871)
Tweezers

Procedure

1. Student will read about Hair Analysis from Background/Theory page. Make sure they understand structure and composition of hair.

2. The instructor will review structures of hair, and show how fiber can be look alike to bare eyes.

3. It is advisable that students observe their own hair sample and any fabric fiber from their own clothes to become familiar with instruments.

4. Students will obtain samples of hairs from the crime scene. Make sure they won’t pick up their own hair accidentally. It is preferred to wear bouffant cap but not required.

5. The instructor will provide the victim and suspects’ hairs.

6. Students will prepare wet or dry mount slide of one of the hairs.

7. Students will use the microscope to observe the hair and record its characteristics including color, thickness, texture.

8. Students will observe hair samples thoroughly for presence of any unique characteristic like splits ends, dye, bleached hair.

9. Students will look for medulla, cuticle and scales, and distribution of pigment granules.

10. Students should not forget to observe root of the hair.

11. Repeat this procedure for the other hair samples and note and record any differences in their laboratory book accordingly.

Analysis and Conclusions:

What can you do if you find a hair sample that has been bleached or dyed?

Do two hair samples from one person supposes to look alike?

What other kinds of physical evidence would you collect that might be useful in the investigation?

What other obstacles do you think there are when you collect physical evidence from a crime scene?

Activity Length

	1 class period for theory and background
	1-2 lab periods for practicing with microscope
	2 lab periods for experimentation and data collection
	1 class period for analyzing and group discussion.
	Research assignment time – presentation and conclusion