Lab 3 assignment



Lab 3: Hair and Fiber Evidence


Several head hairs (1-3 strands)
Several body hairs (1-3 strands)
Several animal hairs (1-3 strands)
Several fibers, colored preferred (1-3 strands)
1 inexpensive magnifying glass (or microscope, if you have one)

Instructions for Lab:

A. When collecting your hair samples, be sure the three samples are “plucked” to insure that the
root is attached to the hair sample.

B. Then, take an additional sampling of “cut” human hair. If possible, obtain each of the plucked and
the cut samples from different donors. This will ensure that you have a variety within your
sampling group.

C. It is best to place your hair samples on a contrasting background. For example, a black hair should be viewed on a white paper background, and a blonde hair on a dark paper background.

D. Using your magnifying glass (or microscope if you have one), examine each sample closely.

Can you identify the following?

1. Cortex

2. Pigment granules

3. Cuticle

4. Medulla

E. Next, take a standard flashlight and turn it on. Place your hair samples on top of the lens as you
hold the light upward. Examine the hair sample from a side view with your magnifying glass. Does
this produce any variances in color or pigment that you did not observe while examining the hair
sample on the paper background?

F. Why was it necessary to have both plucked and cut samples of hair? Does the root of the hair
have value to your microscopic examination, or will the hair root have value in other related lab

Examiners in the lab are specifically looking at the color and the width, distribution pattern of the medulla,
color and distribution pattern of pigment in the cortex, and finally the cuticle pattern. If an examiner finds a
match to each of the above characteristics, the Royal Canadian Mounted Police studies show that there
is a 4,500 to 1 probability that the hair came from the donor (suspect).

Answer questions in sections D (include color and shape of the hair strands), E, and F and describe in
layman terms what the sample looked like to you. Post a one page synopsis of your finding(s),
methodologies utilized, and experience under the thread provided for Lab 3. Review other students’
postings and comment as to how their experiences are either similar or dissimilar to yours.

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