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FORENSIC SCIENCE Trace Evidence Fiber as Evidence. Getting Started 2-20. What are two ways that we can analyze glass?. What is the difference between fabric and fiber?. Fabric- type of material Fibers- threads that make up the fabric. How can fibers be used as evidence?.
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Getting Started 2-20 • What are two ways that we can analyze glass?
What is the difference between fabric and fiber? • Fabric- type of material • Fibers- threads that make up the fabric
How can fibers be used as evidence? • Usually to connect suspect to scene or the victim • Contain greater number of variables so better evidence than soil or rootless hair
How do you collect fibers? • Bag clothing items individually in paper bags. Make sure that different items are not placed on the same surface before being bagged. • Make tape lifts of exposed skin areas of bodies and any inanimate objects • Removed fibers should be folded into a small sheet of paper and stored in a paper bag
Today’s assignments • Shred of Innocence video questions • Fiber Characteristics lab- you need to visit all four tables today (Do the burning before you do the dying station) Make sure you turn in all glass assignments before you leave!!
Synthetic Polyester Rayon Nylon Acetate Acrylic Spandex Natural Silk Cotton Wool Mohair Cashmere What are the types of Fibers?
Cellulose Fibers • Cotton--vegetable fiber. Strong, tough, flexible; moisture absorbent; not shape retentive • Ramie--vegetable fiber. Less flexible than cotton so its often blended with cotton • Rayon--first man-made fiber; soft, lustrous, versatile fiber • Acetate--less expensive, less polluting than rayon
Fiber Comparison Can you tell the difference(s) between the cotton on the left and the rayon on the right?