Forensic Hair Fiber Analysis Review

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

A characteristic that differentiates synthetic fibers from natural fibers is that synthetic fibers —

• are very uniform in diameter

• contain webbing from spiders

• share a common polymer cellulose

• come from minerals that are mined from the ground

Rayon, a regenerated synthetic fiber, can be differentiated from a natural fiber by examining if it contains fibers from —

• cotton

• nylon

• polyester

• cellulose

Tags

NGSS.MS-PS1-3

How would a lab technician be able to differentiate between natural and synthetic fibers using various types of microscopes?

• Natural fibers will be uniform with a distinct shape when a cross section is examined, while synthetic fibers are not uniform.

• All natural fibers will be similar to hair and contain a medulla, cuticle and cortex. Synthetic fibers will be either hollow or solid in center.

• Synthetic fibers will be uniform with a distinct shape when a cross section is examined, while natural fibers are not uniform.

• The only way to confirm if a fiber is synthetic or natural is to chemically analyze it using spectrometry.

What are the differences between the composition of the animal and plant fibers?

• Animal fibers are composed of proteins, while plant fibers are composed of cellulose.

• Animal fibers are composed of cellulose, while plant fibers are composed of proteins.

• Both animal and plant fibers are composed of proteins.

• Both animal and plant fibers are composed of cellulose.

________________________ are derived from animals, plants, or minerals, while some ________________________ are petroleum-based products.

• Natural fibers, synthetic fibers

• Synthetic fibers, natural fibers

• Mineral fibers, animal fibers

• Petroleum fibers, plant fibers

Tags

NGSS.MS-PS1-3

A male was found deceased early one morning. After further analysis of the decedent’s body, a hair was found on his shirt. The medulla portion of the hair was large and patterned. What source did the hair come from?

• Animal

• Human

• Neither

• Not enough information provided

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

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.MS-PS4-2

A man sustained blunt force trauma to his head. A hammer, which was found in close proximity to the man, was collected for evidentiary purposes. A closer look at the hammer revealed hairs on the end of the hammer. How should the hairs be packaged?

• Sealed in an envelope.

• Sealed in a paper bag.

• Sealed in a plastic bag.

• The hairs should be left alone and packaged with the hammer.