Unit 4: Forensic Glass Analysis

Atom

the basic units of the universe

Density

the quantity of something as measured per unit volume, area, and length

Dispersion/Diffraction

“white light separates into its component colors when passing through glass, creating a spectrum.”

Concentric Fracture

fractures that form in a circular pattern around the impact point

Radial Fracture

the first fractures, extends out from impact point and indicates direction of force

Refractive Index (RI)

the measure of how much light bends when passing from air into glass

Becke Line

a bright halo appearing around the edge of a glass fragment immersed in oil

Birefringence

the double refraction of light in a transparent, molecularly ordered material

Fluorescence

the ability of certain chemicals to give off visible light after absorbing radiation which is not normally visible

Crystalline

a solid material whose atoms are arranged in a highly ordered microscopic structure

Amorphous

lacking a crystalline structure

Shards

a sharp piece of broken glass, ceramics, etc.

Intensive Property

properties that are consistent despite sample size, like density, hardness, melting point, etc.

Extensive Property

properties that change depending on the sample size, like mass, volume, surface area, etc.

Mass

the weight/amount of matter in an object

Volume

the measure of the amount of space a 3D object takes up

Flotation Method

a technique commonly used to determine glass density accurately

Microscopy

detailed examination of surface features, fracture patterns, and comparison of glass fragments