When a force pushes on one side of a pane of glass, the elasticity of the glass permits it to bend in the direction of the force applied
. As the first fractures form on the surface opposite that of the penetrating force, and these fractures develop into radial lines.
Do radial or concentric fractures happen 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.
When a projectile hits glass which type of fracture is always produced first?
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 are radial cracks How do they help determine the direction of impact of an object on glass?
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
. Temperature is a measure of heat intensity, or the hotness or coldness of a substance.
What is the difference between radial and concentric cracks?
Concentric cracks are fractures forming in an approximately circular pattern around the point of impact. … Radial cracks are
fractures extending outward from the point of impact
.
What is radial crack?
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
. Concentric Fracture – A crack in a glass that forms a rough circle.
What are the 2 types of glass fractures cracks?
When a projectile i.e. a bullet or rock hits the glass, it will form two distinct types of fractures:
Radial and Concentric
.
What are the two most often used methods of glass analysis?
The
flotation and immersion methods
are best used to determine a glass fragment’s density and refractive index, respectively.
When a glass is broken radial cracks form a right angle on the reverse side of the force?
What is the
3r
rule for glass fractures? What is the 3R rule and how is it applied to the analysis of glass fractures? The 3R rule states that Radial cracks form a Right angle on the Reverse side of the force. This rule enables an examiner to determine readily the side on which a window or pane of glass was broken.
What is the 3R rule?
The three R’s stands for:
Reduce, Reuse and Recycle
. This rule is part of the waste hierarchy which is a process used to protect the environment and conserve resources through a priority approach. The aim is to get the most practical benefits from products and to generate the minimum amount of waste.
What are two morphological characteristics criminalist?
What two morphological characteristics does a criminalist first compare when examining fibers with a microscope? What other features may be important in such a comparison?
Color and diameter
. Other features would include lengthwise striations and the cross sectional shape of a fiber.
What will not be visible if a glass and a liquid has the same refractive index?
Explanation:If glass rod is immersed in a liquid of a same refractive index then it will
disappear
. … So if refractive index is same then light will never reflect or refract at the interface & object will appear to disappear.
What property is used to identify glass and match it to glass at a crime scene?
Refractive index (RI)
is a unique property of any type of glass that can be used to compare a sample to a source, such as a broken window in someone’s home.
What tests are conducted on glass as evidence?
Glass: Glass can yield valuable information through fracture marks, lines and patterns. Testing for unique characteristics such
as color, optical properties and density
can determine the type of glass, for example a window pane, vase or glass bottle.
When a bullet goes through a glass window the exit hole is bigger than the entry hole?
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.
The cone of glass
makes the exit hole: larger than the entrance hole of the bullet.
What side of a bullet hole in glass is larger?
Examination of the hole (if there is one) will identify whether the object was a low velocity or high velocity projectile. A bullet at high velocity produces a hole in the glass where
the exit side is wider than the entry side
.
