Forensic Science CH3/CH4

What fibers were used to make clothing until the nineteenth century?

Only plant or animal fibers.

What percentage of fibers produced today are synthetic?

Half.

What are the categories of fibers produced today?

Regenerated fibers and polymers.

What type of evidence is hair considered in criminal investigations?

Trace evidence.

What is the most common stem fiber used in textiles?

Flax.

How many layers make up the hair shaft?

Three layers.

What is the largest part of the hair shaft?

Cortex.

How many types of hair are distinguished on the human body?

Six.

How are fibers classified?

Natural fibers or synthetic fibers.

What type of evidence is hair considered?

Class evidence.

What is fiberglass a fiber form of?

Glass.

What common polymer do all plant fibers share?

Cellulose.

What is the central core of a hair fiber called?

Medulla.

What is the simplest weave pattern?

Tabby weave.

What type of protein makes hair strong and flexible?

Keratin.

What is the estimated amount of fibers lost within 24 hours of a crime?

95%.

What is the term for the transfer of evidence from one person to another?

Secondary transfer.

What is the cuticle of human hair described as?

Imbricate.

What type of studies does The Hair of Man and Animals include?

Microscopic studies of hair from most domesticated animals.

What are fibers that have been spun together called?

Yarn.

What principle states that some transfer of material occurs when two objects are in contact?

Locard's Principle of Exchange.

What is a small molecule that may bond to other monomers to become a polymer?

Monomer.

What is the main purpose of hair in mammals?

Regulate body temperature.

At what rate does human hair grow?

1.3 cm per month.

When was the comparison microscope first used for hair analysis?

1934.

What is Manila fiber extracted from?

Leaves of abaca, a relative of the banana tree.

What tools are used to gather fiber evidence?

Vacuums, tape, forceps, lint roller.

How many stages does hair proceed through as it develops?

Three stages.