Unit 3 Trace Evidence

Forensics

Compound Microscope

used for higher levels of magnification/viewing smaller specimens, and consists of multiple lenses.

Stereo Microscope

used for preliminary examinations/ looking at large and whole objects such as clothing,debris, and vehicles, consists of one lense.

Comparison Microscope

used for comparing evidence side-by-side such as bullets, fibers, hair, and consists of two mciroscopes.

Trace evidence

tiny pieces of evidence that connects people/objects. ( hair, fibers, soil, gun residue, etc)

Forceps (Tweezers)

First best way to collect trace evidence.

Dab with clear tape til dry.

Second best way to collect trace evidence.

Vacuuming

third best way to collect trace evidence but is known for being unreliable.

The root

What must be present to be able to test the hair for nuclear DNA?

It only shows what who people are related to (Not very unique).

Why is mitochondrial DNA not as helpful?

Coral scales, Spinous scales, and Imbricate scales.

What are the 3 types of cuticles found in hair?

The cortex

what contains pigment granules which are absent in light hair?

Absent Medulla

What medulla is this?

Fragmented medulla

What type of medulla is this?

Continuous medulla

What type of medulla is this?

Interrupted Medulla

What type of medulla is this?

Lattice medulla

What type of medulla is this?

Ladder Medulla

What type of medulla is this?

It can link a person to a location and it has a larger medulla.

Two facts about Animal hair…

½ inch every month or 1 cm

How quickly does hair grow?

50 strands of full length from various areas of the scalp.

when collecting hair samples, how many strands of hair must be obtained?

A person’s travel history.

What can analysis of isotope ratios in hair tell investigators?

Henry Paul ( drug use that was incomparable with alcohol)

According to the judge, who was responsible for the accident that killed princess Diana?

Napoleon.

Who died from stomach cancer?

Synthetic fiber

Man-made, smooth edges, repeating segments. ( Lycra, nylon, spandex, polyester).N

Natural fiber

Plants + Animals, rough edges, less uniformity. ( silk, wool, cotton, hemp, linen).

Location + time of the year

What can pollen on a car tell investigators?