Fibres and FabricsFibres can be an important trace element at a crime scene. They may have come from a large number of sources including:• The criminals clothes• Carpet or curtains at the crime scene• A rug or blanket used to move a body

Fibres and FabricsFibres can either be synthetic (man made) or natural (from plants or animals)

Synthetic Fibres Natural Fibres from Plants

Natural Fibres from Plants

NylonPolyesterCarbon fibreRayon

CottonLinenHempFlax

WoolSilkMohair

Fibres and FabricsDifferent fibres have different properties such as strength and thickness. These properties can be used to compare fibres from a crime scene to those found on a criminal.

Webquest Questions1. Explain how fibres can be important evidence in the solving

of a crime?2. Try to find the name of 6 different fibres (two synthetic,

two from animals, and two from plants and compare their properties in a table similar to below?

3. Using the information in your table, what test forensic would you perform for comparing fibres?

Fabric Name Strength Thickness of strand

Flammability or Melting point

Common uses

Example: Cotton Strong fabric 250 degrees C Clothing, medical supplies

Homework

Write a short description of a criminal case in which fibres were used as important forensic evidence?

Fibre Burn Test

http://youtu.be/4rvC7E4iaUYhttp://www.youtube.com/watch?v=1M_Kr1Y9etY