What causes radial fractures to be longer or shorter in glass? Fracture patterns are unique. Fracture features in a piece of glass
reflect the nature of the glass and the direction of travel and velocity of the breaking object
. Glass fracture examinations can provide information as to the direction of the breaking force and the sequence of multiple impacts.
Why does broken glass produce different fracture patterns?
Fracture patterns are unique. Fracture features in a piece of glass
reflect the nature of the glass and the direction of travel and velocity of the breaking object
. Glass fracture examinations can provide information as to the direction of the breaking force and the sequence of multiple impacts.
What factors contribute to the resulting characteristics of the glass fracture?
Where do radial fractures first occur on glass?
What fracture pattern does glass have?
When examining glass fractures What characteristic helps to determine the direction of the projectile creating the fractures?
Concentric fracture- A crack in a glass that forms a rough circle around the point of impact. By analysing the radial and concentric fracture pattern in glass, the forensic scientist can determine the direction of impact by applying the
3R rule
: Radial cracks form a Right angle on he Reverse side of the force.
Where are radial fractures in glass?
Radial Fracture – A crack in a gloss that
extends outward like the spoke of a wheel from the point at which the glass was struck
.
What causes glass to fracture?
Spontaneous breakage of tempered glass is most commonly caused by chipped or nicked edges during installation, stress caused by binding in the frame, internal defects such as nickel sulfide inclusions, thermal stresses in the glass, and inadequate thickness to resist high wind loads.
What is the difference between concentric and radial glass fractures?
a. In a radial glass fracture, the fracture lines move outward from the point of impact. In a concentric glass fracture, the fracture lines occur in circles that share a center (the center is found at the point of impact).
Which statement is true about the fracturing of glass?
| Question Answer | which is a true statement about the fracturing of glass? radial cracks appear first, starting on the side opposite the destructive force . | The fracture pattern of glass usually has radial and concentric lines |
|---|
When impacted glass will break first on the weaker side the side?
Glass will break first on the weaker side, the side:
opposite the strike
. Radial fractures will result. As a bullet passes through glass, it pushes some glass ahead of it, causing a cone-shaped piece of glass to exit along with the bullet.
What does a radial fracture look like in glass?
Radial fractures are
similar to the spokes of a wheel
. When a projectile strikes glass, it creates ridges called conchoidal fractures along the edge that are visible in profile. These conchoidal fractures are nearly parallel to the side in which force was applied (the direction which the projectile came from).
What happens when bullets fractures glass?
“In the case of bullet holes or small punctures in glass, cracks will form around the hole. Radial cracks will radiate outward from the hole, like petals from a flower. Another set of cracks will develop as a series of concentric circles, like ripples. In either case, cracks will end at existing cracks.
How are radial fractures formed?
How might a forensic scientist tell which of two fractures on a piece of glass was invented earlier?
How might a forensic scientist tell which of two fractures on a piece of glass was created earlier?
They can observe the fracture lines and their points of termination
.
What are the sources of flaws in glass?
Weakening caused by heat-treating glass is attributed to
surface dehydration and incorporation of dirt in the surface
. Time-dependent strength effects at room temperature are attributed to moisture. Depending on the glass surface condition and state of stress moisture may cause weakening or strengthening.
Why do glass spheres break into cones?
What can a forensic examiner determine by the analysis of fractured window panes?
How can the shape of fractures in glass tell an investigator something about the crime scene?
How glass cracks and fractures help investigators solve a crime?
Fractured and fragmented glasses are most commonly encountered at the crime scene. During the commission of the crime,
glass breaks and shatters into fragments or into minute particles that serve as trace evidence and may provide a significant lead for the probe
.
What is radial fracture?
How does the fracture pattern of tempered glass reduce serious injuries?
When tempered glass is broken (as shown above),
it shatters into thousands of tiny pebbles
, practically eliminating the danger of human injury caused by sharp edges and flying shards of glass. The surface compression of heat-strengthened glass makes it approximately twice as strong as annealed glass.
What is the process used to increase the strength of glass?
When an object begins to penetrate a pane of glass concentric fractures are the first to form?
When an object begins to penetrate a pane of glass,
concentric fractures are the first to form
. A bullet passing through a pane of glass will not cause the glass to shatter. A non-bullet projectile passing through a pane of glass will always cause the glass to shatter.
What are the two most important physical properties of glass for forensic comparisons?
To compare glass fragments, a forensic scientist evaluates two important physical properties:
density and refractive index
.
Which glass fracture comes first?
You can see how the glass is stretched. This stretching causes the concentric fractures.
Radial fractures occur first on side OPPOSITE the force
. Concentric fractures occur second on SAME side as force.
What are the 3 types of glass fracture?
What is the 3R rule for glass fractures?
The Becke line as seen on the right is outside of the glass, indicating just the opposite. 3R rule—
radial cracks form a right angle on the reverse side of the force
.
What is rib marks in glass?
How can you tell which side of a glass is broken?
Why is it important to collect all the glass from a scene?
INTRODUCTION – The value of glass fragments as evidence is not always fully recognized. Windows, automobile glass, broken bottles, and other glass objects
may be crucial evidence in burglaries, murders, hit-and-run and many other types of crime
.
Why are stress marks in glass important?
What is a concentric fracture in glass?
Concentric cracks are
fractures forming in an approximately circular pattern around the point of impact
. They are usually in straight segments that terminate in an existing radial crack.
Why does glass crack like a spider web?
Flat glass laid on the ground and hit with a hammer also produces these radial cracks from the centre of impact. This is
caused by the rigidly flat surface trying to form a cone shape
. You can only cut triangles (around a point) in a flat surface, and allow those triangles to spread apart at the apex to form a cone.
Which is a true statement about the fracturing of glass?
| Question Answer | which is a true statement about the fracturing of glass? radial cracks appear first, starting on the side opposite the destructive force. | The fracture pattern of glass usually has radial and concentric lines |
|---|
What are the different ways to determine the direction of force within glass?
Direction of force determinations: This method determines which direction a projectile went through the glass by
evaluating radial fractures in the glass fracture’s first concentric ring
. The determination of force direction is a process easily done by a crime scene technician.
