Presentation on theme: "What is the state of matter of glass at room temperature?"— Presentation transcript:
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.
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 or False, when glass shatters it is easy to reconstruct the original shape.
This type of glass involves a treatment where the glass is heated to 620 o 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.
This type of conchoidal line appears first when glass is fractured.
For a ______________ fracture, the perpendicular end, faces the surface on which the force originated.
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.
True or False A crater-shaped hole is narrower on the side where the projectile entered the glass.
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.
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 _________.
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 ________.
As light goes from the air into a liquid sample, the bending of light is due to a(n) ___________ in velocity of the light.
At 25 o C the refractive index of water is 1.333. This means that light travels 1.333x __________ in a vacuum than in water.
______________ solids Refract a beam of light in two different light-ray components (wavelengths) Results in double refraction
The numerical difference between these the two refractive indices of a crystalline solid is known as ________________.
Technique used to determine the refractive index of a glass sample is known as the _____________ method.
As the velocity of a fast moving projectile decreases, the irregularity of hole and cracks ____________.
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.
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 ________.
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: