Ch. 10: Soil & Glass Analysis

Physically fitting a missing piece of glass into the original would produce an individual characteristic

True

If a Becke line disappears, it is known as the match point.

True

Dark soils contain mostly clay.

False

soil would most often be considered class evidence

True

Refractive index is a physical property of all materials that transmit light

True

A substance that fluoresces in the soil would be considered individual evidence

False

Finding the refractive index of soils is a good way to characterize them

False

The first glass was thought to have been made around 25 AD

False

Specific gravity is the ratio of the density of a substance to that of water

True

Sometimes certain materials within soil will fluoresce

True

quartz is usually found at the bottom of a density gradient

True

The presence of artifacts in the soil prohibits forensic investigations of that soil

False

A mineral is defined as any naturally occurring crystalline solid

True

Glass is primarily made of silica

True

the use of a magnet would help in identifying limestone in soil

False

Glass is made of sand:

and heated glass, with chemicals added to change its properties, with metals added for color

The organic part of soil is called:

humus

Glass evidence is considered:

sometimes individual, sometimes class depending on the circumstances

A man claims that someone broke into his house through the window; the investigator believes that the window was broken from the inside of the house. What evidence would lead the investigator to believe this?

The edge of the window had stress marks perpendicular to the outside and parallel to the inside

A glass fragment is dropped into a test tube filled with a particular liquid. If the fragment is suspended in the middle of the liquid, the density of the fragment is _____ the density of the liquid.

equal to

If two fracture lines meet, it is easy to determine which fracture occurred first because:

the fracture line will terminate at the crack that happened first

The forensic definition of soil is:

a mixture of mineral grains, organic matter, and any other materials mixed with the sample

Glass is considered to be:

an amorphous solid

The amounts of light transmitted through a sample can be measured as a function of wavelength through which procedure?

spectroscopy

The refractive index of a glass fragment:

is a physical property of the glass regardless of its size and can be determined making the fragment disappear in a liquid of known refractive index

soil evidence is analyzed based on its

Physical properties, chemical properties, settling rate

A piece of glass has a bullet hole that is larger on one side of the glass than on the other. This indicates:

the larger side is the exit

A soil horizon is something that shows

a soil profile showing distinct layers

Which of the following statements is not a physical property of a material or substance?

evolution of bubbles when another substance is added

Another term for a known source would be:

an exemplar

The major difference between clay and sand is:

particle size

it is useful to find the becke line when examining

refractive index

because of iron oxide in the sand, the natural color of glass is

slightly green

a technique frequently used to compare glass samples is

the use of density gradient tubes, use of the Becke line, flotation

A glass fragment is dropped into a test tube filled with a particular liquid. If the fragment floats on the surface, the density of the glass is ____ the density of the liquid.

equal to

In examining a glass fracture pattern, the radial lines are:

cracks that extend out from the point of impact

A topographic map is one that shows:

the geographic features of an area

Density is defined as

Mass per unit volume

Refraction

The bending of a lightware due to a change in velocity

Comparison

Process of determining whether two or more objects have a common origin

Density

Mass per unit volume

Mass

refers to the amount of matter an object contains

Physical

property that does not cause a change in the substance's structure

Identification

process of determining a substance's physical or chemical identity

Double Refraction

the refraction of a beam of light into two different light rays

Product Rule

frequency by which a certain type of evidence appears in nature or the real world

Associative

value of the physical evidence that places a suspect at a crime

Becke Line

the halo that is observed near the border of a particle that is immersed in a liquid

Chemical

property that causes a change within the substance's structure

Dispersion

the process of separating light into component color

Birefringence

difference between two refractive indices of a solid (like a crystal) that gives the appearance of two colors

Chemical

two examples are burning or adding hydrochloric acid

Match Point

the disappearance of the Becke line

Weight

Force with which gravity attracts a body

Physical

two examples are boiling point and melting point

Probative

value of the physical evidence that provides a certain level of proof

Briefly discuss three factors that influence soil composition.

Climate, living organisms, what happens over time

Discuss the work done by Georg Popp. What was its significance?

He was the first person to learn how to differentiate different soils, established forensic geology

How do you determine the order of the bullet holes fired?

The radial lines