Chapter 17: Soil and Glass

Microscope

Microscope

The most important tool in the forensic soil scientists toolbox.

Becke Line Method

A technique in optical mineralogy that helps determine the relative refractive index of two materials.

Dusty dry soils

Tend to be light tan or white owing to lack of moisture.

Humus

Collective organic fraction of soil.

Fracture match

________; where glass can be individualized to a particular object.

Soil

Earth material, either natural or man-made (concrete, gravel, other building materials), that is transferred from a crime scene to a person or object, or vice versa.

Radial Cracks

Will form on the side of the glass opposite to the side of the impact.

high speed projectile

When a(n) ________, such as a bullet, passes through a piece of glass, a crater will form in the glass that is larger on the exit side of the glass.

Glass

An amorphous solid; a hard, brittle material that is usually transparent, but which lacks the ordered arrangement of atoms.

Flat glass

Used to make windows and windshields and can also be shaped to form light bulbs, headlights, and other materials.

Concentric Cracks

Fractures forming in an approximately circular pattern around the point of impact.

Borosilicate Glass

Used in cookware, thermometers, and automobile headlights because it can take fast, extreme changes in temperature without cracking or shattering.

Particle analysis

The key to understanding the nature of the samples under examination.

Soil

________ contains both organic and inorganic materials.

Common glass

made up largely of oxides of silicons that have been doped with other materials to give it its familiar properties

Float glass

made by pouring the molten glass from a furnace into a chamber that contains a bed of molten tin

Soda Lime Glass

made when calcium oxide and sodium carbonate are added

Borosilicate Glass

used in cookware, thermometers, and automobile headlights because it can take fast, extreme changes in temperature without cracking or shattering

Tempering

a process whereby the glass is heated and cooled rapidly, producing deliberate stress in the surface

Flat glass

used to make windows and windshields and can also be shaped to form light bulbs, headlights, and other materials

Container glass

used to make bottles and drinking glasses

Glass Refractive Index Measuring Instrument (GRIM)

used in most forensic science laboratories to determine the refractive index of small glass particles

Radial Cracks

will form on the side of the glass opposite to the side of the impact