Glass & Soil Review - Duluth High School

Report
•What is the state of
matter of glass at room
temperature?
•It is an amorphous solid.
The main compounds in
glass are __________.
Silicon Oxides & Metal
Oxides
•What is the name of the
glass that is made by
passing the molten glass
through rollers?
•Ordinary or rolled glass
•Window glass is
(more/less) dense than
water.
More dense
The two most important
physical properties of
glass used for
identification are:
•Density and refractive
index
True or False
•Density is not
homogeneous over sheet of
glass
•True
True or False, when glass
shatters it is easy to
reconstruct the original
shape.
•false
•This type of glass involves a
treatment where the glass is
o
heated to 620 C and then
cooled rapidly. What is the
name of this glass?
•Tempered or Safety
Glass
•Name the type of glass
that is used for flat glass,
container glass, and
electric light bulbs.
•Soda Lime Silicate
•The fracture pattern of
glass usually has
__________ lines.
•Conchoidal
•This type of conchoidal
line appears first when
glass is fractured.
•Radial
For a ______________
fracture, the
perpendicular end, faces
the surface on which the
force originated.
•concentric
•In a forensic laboratory,
a technique frequently
used to determine the
density of glass involves
the use of ___________
•Density – Gradient tubes
•Stress marks on the edge of
a radial crack near the
point of impact are
___________ to the side on
which the force was
applied.
•parallel
True or False
A crater-shaped hole is
narrower on the side where
the projectile entered the
glass.
True
True or False –
It is easy to determine from the
size and shape of a hole in
glass, whether to was made by a
bullet or some other projectile.
False
A piece of window glass is submerged
in vegetable oil. The outline of the
glass is visible. When light is shown
behind the glass, a bright halo appears
near the border of the glass. This
bright halo is called a _________.
•Becke line
Laminate or laminated
Name at least one out of
three common problems
associated with glass
analysis (glass comparisons)
•Find and measure properties
•Associate one glass
fragment with another
•Minimize or eliminate other
sources
•The bending of light as it
travels through one medium
into another is known as
________.
Refraction
As light goes from the air into
a liquid sample, the bending
of light is due to a(n)
___________ in velocity of
the light.
•decrease
o
25 C
At
the refractive index
of water is 1.333. This means
that light travels 1.333x
__________ in a vacuum
than in water.
•Faster
______________ 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
•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
Radial
True or False
All broken glass at a crime
scene must be collected,
regardless of the size.
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
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. Seeds
2. Cinders
10. Animal matter
3. Asphalt
11. Spores
4. paint
5. metals
6. concrete
7. Bricks
8. 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 False
Soils 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

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