Forensic Fiber Analysis

Fibers are commonly examined by a microscope that changes typical scattered light wavelengths into wavelengths that vibrate in only one direction, which enhances contrast. This process describes which microscopy analysis?

• A Polarizing Microscopy

• B Comparison Microscopy

• C Oblique Lighting Microscopy

• D Transmission Electron Microscopy

Tags

NGSS.HS-PS4-3

When examining a fiber using a polarizing microscope, the characteristic that would distinguish a textile fiber from an animal hair is —

• presence of cuticle scales

• a crystalline structure

• melanin in cortex

• a uniform diameter

If the hairs were an exact match when compared under a microscope, is that enough to place the suspect in jail? Why or why not?

• Yes, because a microscopic match is conclusive evidence.

• No, does not contain the root, no DNA, so this is class evidence

• Yes, because it proves the suspect was at the crime scene.

• No, because hair evidence is not admissible in court.

Which two characteristics of a hair help determine if the hair came from a human or animal?

• Medulla pattern and cuticle type

• Color and length

• Thickness and texture

• Curliness and elasticity

Which of the following observations are used to help identify a specific fiber?

• smell of the burned fiber

• on contact with the flame, does the fiber coil or melt?

• color and structure of the residue left after the fiber burn

• all of the above

Tags

NGSS.MS-PS1-2

The transfer of evidence such as a fiber from a source to a person, then to another person, is called:

• direct transfer

• absolute transfer

• source transfer

• secondary transfer

When fibers are transferred straight from victim to suspect or suspect to victim, this is called:

• necessary transfer

• direct transfer

• absolute transfer

• secondary transfer

At a crime scene, investigators collect blood, hair, and fibers that need to be packaged. What is the best method of packaging the evidence?

• Package hairs and fibers together and biological materials separately

• Package all evidence in paper bags with a proper seal

• Package all evidence separately in the appropriate container

• All evidence will be collected and packaged together

When observing a cat hair image under the microscope, it is possible to contrast it to a human hair by observing the —

• DNA

• distribution of pigment

• medullary pattern

• presence of keratin

Tags

NGSS.MS-LS4-2

The table shows different sources from which natural fibers are made. What fiber types correctly complete the table?

• Animal, Mineral, Plant

• Mineral, Animal, Plant

• Plant, Animal, Mineral

• Plant, Mineral, Animal