Chapter 4: A Study of Fibers + Textiles Flashcards
1
Q
Characteristics of Fibers
A
- create a link between crime and suspect
- trace evidence
- locardś exchange principle
- direct transfer
- secondary transder > victim picked up the fibers and transferred them
- early collection is important - 24hrs
- only fibers you would not expect to find
2
Q
How do forensic scientists use fibers?
A
- type
- color
- # of fibers
- where the fiber is found
- textile the fiber came from
- multiple fiber transfers
- type of crime committed
- time between crime & discovery of the fiber
3
Q
How are fibers collected?
A
- vacuums
- sticky tape
- forceps
- be accurate!
4
Q
Most common form of fiber transfer is shedding of a ____
A
textile
5
Q
Steps to Taking a Fiber
A
- Identify the color/shape/type
- Match it to fibers from the suspects source such as a car or house
- One fiber
- More than one
6
Q
Examples of Textiles
A
clothing, carpets & upholstery
7
Q
How are they made?
A
weaving or intertwining yarns together
8
Q
How is yarn made?
A
fibers that are spun together
9
Q
What are the 2 types of fibers?
A
natural and synthetic
10
Q
Where do natural fibers come from?
A
plants, animals, and minerals mined from the ground
11
Q
Silk
A
- cocoons of the caterpillar
- shimmering appearance is caused by the triangular structure of the fiber. It scatters light
- clothing and bedding
- doesn´t easily shed
12
Q
Minerals
A
- neither protein or cellulose
- ex. fiberglass > fibers are very short, weak and brittle. Used as insulation
- asbestos > durable. Used in brake linings, ceiling tiles, floor tiles
13
Q
Plant
A
- specialized plant cells
- grouped from the part of the plant they come from
- seeds, fruits, stems & leaves all produce plant fibers
- all have diff. characteristics
- most common is cotton
- short > 2-5cm
- become brittle over time
- trace evidence
14
Q
Animal Fibers
A
- can come from 3 sources: hair, fur and webbing
- all are made of proteins
- used in clothing, carpets, curtains & bedding
15
Q
Regenerated Fibers
A
- made from cellulose and are mostly plant
- ex. rayon - found in carpets
