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Hairs & Fibers Name ____________________________

Hair Evidence

1. ___________ is one of the most common forms of trace evidence. The examination of human hairs in the forensic

laboratory is conducted through the use of ___________ __________________. The examination involves the

____________________ of questioned hairs and the ____________________ of questioned and known hairs.

2. The first step in the hair examination process is to determine whether the hair in question originated from an

________________ or a ________________

3. Hair is an outgrowth of the __________ and is produced from a structure called the hair ________________

Humans develop hair follicles during _________ development and no new follicles are produced after _________.

Hair is composed of the protein ____________, which is the primary component of finger and toe _________.

4. Hair color is mostly the result of ______________, which are chemical compounds which reflect certain

wavelengths of visible light. Hair color may also be influenced by the optical effects of light ______________ and

bouncing off the surfaces of the different hair.

5. Hair ___________ (round or oval) and _____________ (curly or straight) is influenced heavily by

_______________. Nutritional status and intentional alteration (heat curling, "perms") can affect the

_______________ appearance of hair.

6. The ___________ ___________ from which a hair originated can be determined by the sample’s length, shape, size,

color, stiffness, curliness, microscopic appearance, pigmentation, and the appearance of the medulla.

Hair Structure

7. Hair is composed of three principal parts:

_______________ – outer coating composed of overlapping scales

_______________ – protein-rich structure around the medulla

_______________ – central core (may be absent in some species)

8. Label the diagram by drawing lines from each part listed in #4. 9. The structure of hair has been compared to that of a ________________ with the medulla being the ___________, the cortex being the ___________ and the cuticle being the ___________ on the outside. 10. What must be present in a hair sample in order to perform DNA testing? ____________________________

T. Trimpe 2006 http://sciencespot.net/

Fiber Evidence 11. A ________________ is the smallest unit of a textile material that has a ________________ many times greater

than its ________________.

12. Fibers can occur ________________ as plant and animal fibers, but they can also be _______-_________. A fiber

can be spun with other fibers to form a ________________ that can be woven or knitted to form a fabric.

13. The __________ and ________________ of fiber used, the type of _______________ method, and the type of

________________ construction all affect the transfer of fibers and the significance of fiber associations. This

becomes very important when there is a possibility of fiber _______________ between a suspect and a victim during

the commission of a crime.

14. Matching dyed ________________ fibers or dyed ________________ fibers on the clothing of a victim to fibers

on a suspect’s clothing can be very helpful to an investigation, whereas the matching of ________________ fibers

such as white cotton or blue denim cotton would be less helpful.

15. The discovery of ________________ ________________ and multiple fiber transfers between the suspect's

clothing and the victim's clothing dramatically ________________ the likelihood that these two individuals had

physical contact.

16. What plant fiber is most commonly used in textiles? _________________________ 17. What animal fiber is most commonly used in textiles? ___________________________ 18. More than half of all fibers used in the production of textile materials are _________-_____________.