Forensic Glass Questions

Master forensic glass analysis! Explore fracture patterns & properties.

Radical fracture A crack in the glass that extends outward like the spoke of a wheel from the point at which the glass was struck Concentric fracture A crack in the glass from a rough circle around the point of impact Silicon dioxide SiO2 the chemical name for silica; the main component of glass Soda Lead Also known as crystal Amorphous Without shape or form; applied to glass, it refers to having particles that are arranged randomly instead of in a definite pattern Density The ratio of the mass of an object to its volume, expressed by the equation X = mass Refraction Index The change in the direction of light as it changes speed when moving from one substance into another Glass A hard, amorphous, transparent material made by heating a mixture of sand and other additives Glass containing lead oxide. Soda Lime Glass Soda Lead Glass Tempered Glass Laminated Glass Two sheets of ordinary glass bonded together with a plastic film Soda Lime Leaded Glass Tempered Glass Laminated Glass The most common glass, which is inexpensive, and easy to melt and shape Soda Lime Soda Lead Tempered Laminated Glass which is strengthened by introducing stress through rapid heating and cooling of its surface. Soda Lime Soda Lead Tempered Laminated What is the main ingredient in glass? Sand (SiO2) Soda (NaO) Metal Oxides Lime (CaO) Tempered glass is used in Windshields in autos manufactured in the US Crystal Stemware The side and rear windows of autos manufactured in the US Both b and c When a bullet penetrates a panel of glass, it leaves a crater shaped hole that Is wider on the exit side Is wider on the entrance side Forms randomly; the direction of impact cannot be determined by its appearance Both b and c Which statement is true about the fracturing of glass? Concentric fractures form first on the same side as the destructive force Radial cracks form afterwards, starting on the same side as the destructive force Radial cracks and concentric fractures are formed simultaneously Radial cracks appear first starting on the side opposite the destructive force A piece of glass is immersed in a liquid, and it proceeds to float on the surface. This shows that the density of the glass is _ the density of the liquid. equal to less than more than not comparable If glass cannot be physically pieced together, the control and questioned glass are best compared by their Weight and density color and density Refractive Index and Density Refractive Index and Weight The smaller opening of a crater-shaped hole in glass made by a projectile indicates the Exit side of the glass Entrance side of the glass The projectile was traveling at a low velocity That a bullet made the opening The fracture pattern of glass usually has Radial and concentric lines Concentric Lines Radial Lines Directional Lines Refractive index measures the speed of light in a vacuum, to its speed in Air Water Glass Any given substance The formula for calculating density of an object is mass per unit volume. True False The only way to analyze glass fragments at a crime scene is to assemble the fragments and physically fit them together like a jigsaw puzzle. True False It is possible to determine the sequence of impact by observing the existing fracture lines and their points of termination. True False Referencing the diagram below what is the correct sequence of impact. A First B First A and B Simultaneously Sequence impossible to determine