1. Fiber Transfer Activity

2. Rub your sleeve against your neighbor’s sleeve
Rub your sleeve against your neighbor’s sleeve. Then answer the following questions:
Can fibers from one sleeve be detected on the other?
Do hand lenses or masking tape aid the investigation? How?

3. Fiber Analysis

4. Introduction to Fibers
Trace evidence
Class evidence
Direct transfer: suspect  victim
Secondary transfer: source  suspect  victim
95% of fibers lost from crime scene within 24 hours

5. Forensic scientist determines:
Type of fiber
Color
How many of each kind
Textile origin
Multiple Fibers
Transfers
Type of crime

6. Fiber Evidence Collected by: Special vacuums (large areas) Sticky tape
Forceps
Tested by:
Microscopy – polarizing light, infrared
Burn test (large quantities only)

7. Fibers are spun into yarns that have specific characteristics
Yarns are woven, with different patterns, into textiles
Fibers may be natural or synthetic

8. Fiber Classification (Use textbook p. 81-84)
Natural Fibers:
(List the different types and examples of each)
Synthetic Fibers:
(List the different types and examples of each)

9. Natural Fibers Animal fibers (protein) Plant fibers (cellulose)
Sheep – wool
Goats – cashmere, mohair
Rabbits – angora
Caterpillar – silk
Plant fibers (cellulose)
Seed: cotton
Fruit: coir (coconut)
Stem: hemp (Cannabis), jute, flax (linen)
Leaf: manila, sisal
Mineral fibers
Fiberglass (glass) , asbestos (rock mineral)

10. WOOL
COTTON
FIBERGLASS

11. ASBESTOS
FLAX
JUTE

12. SILK
HEMP

13. Synthetic (Man-made) Fibers
Regenerated fibers (modified natural fibers)
Rayon
Celanese
Capron
Synthetic polymer fibers
Polyester
Nylon
Acrylic
Olefins