GLASS & SOIL REVIEW – PART 2

______________ solids Refract a beam of light in two different light-ray components (wavelengths)

Results in double refraction

Crystalline

The numerical difference between these the two refractive indices of a crystalline solid is known as ________________.

Birefringence

This is an example of.. . . . . .

Birefringence

Technique used to determine the refractive index of a glass sample is known as the _____________ method.

Immersion

As the velocity of a fast moving projectile decreases, the irregularity of hole and cracks ____________.

increase

Exhibit (a) only shows a __________ fracture

Radial

Glass Collection

True or False

All broken glass at a crime scene must be collected, regardless of the size.

FALSE

Know ALL of these steps for Glass collection Collect all glass found for piecing Submit all glass evidence found

in the possession of the suspect Collect only a representative

sample of broken glass remaining at the crime scene

True or False

Once collected glass should be wrapped up in paper to prevent further damage.

False,

Packaged in solid containers to avoid further breakage

Soil Collection

Standard/reference soils should be taken from the crime scene at various intervals within a ______-yard radius of the crime scene.

This will be used as a comparison to questioned soil.

100

Soil is a mixture of _______ and _________ material.

Soil is a mixture of organic and inorganic material.

An example of 100% inorganic soil is _________while an example of a nearly 100% organic soil would is ________.

An example of 100% inorganic soil is sand while an example of a nearly 100% organic soil would is peat.

The inorganic part of soil is ________.

minerals

The organic part of soil is known as _______ which is made up of __________________.

Humas

decayed plant and animal material

The forensic definition of soil includes many things, including:

1. Bits of grass 9. Seeds2. Cinders 10. Animal matter3. Asphalt 11. Spores4. paint5. metals 6. concrete 7. Bricks8. Vegetation

List the five major factors that influence a soil’s composition.

1. Climate

2. Parent material

3. Living organisms

4. Topography

5. Time

True or False

Soil is class evidence - cannot be individualized to a particular location

True

True or False• There is no classification system for soils

True – only guidelines

True or FalseSoils can be easily transported

True – which makes it excellent trace evidence.

True or False

Soils within a few meters horizontally or vertically differ

True

True or False

After removing the first 2- 3 inches of top soil, a forensic soil analyst can tell if a body has been buried below.

True