Forensic Fiber Analysis Quiz

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

What class characteristics of hairs are used by lab technicians to either rule out a suspect or determine if further analysis is needed to confirm consistency with crime scene samples?

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

A characteristic that differentiates natural fibers and synthetic fibers is that natural fibers are —

• regenerated

• heat tolerant

• petroleum base

• resistant to microorganisms

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

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

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.

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

________________________ 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