FRSC 2001 – Introduction FRSC 2001 – Introduction to Forensic Science to Forensic Science

Technology IITechnology II

Trace Evidence Part I:Trace Evidence Part I:Glass, Paint, and Soil EvidenceGlass, Paint, and Soil Evidence

Professor BensleyProfessor Bensley

Alfred State CollegeAlfred State College

Trace EvidenceTrace Evidence

Very common form of physical Very common form of physical evidenceevidence

Name some examples of trace Name some examples of trace evidence….evidence….Locard Exchange PrincipleLocard Exchange Principle

When a person comes in contact with another person or an object, a cross-transfer of materials occurs

Types of GlassTypes of Glass

Soda-lime glassSoda-lime glass Most window and bottle glassMost window and bottle glass

Types of GlassTypes of Glass

Float GlassFloat Glass Type of soda-lime glass – Produces Type of soda-lime glass – Produces veryvery

flat glass used in windows (plate glass flat glass used in windows (plate glass windows)windows)

Types of GlassTypes of Glass

BorosilicatesBorosilicates Automobile headlights, heat-resistant Automobile headlights, heat-resistant

glass like Pyrex – add Boron oxide to the glass like Pyrex – add Boron oxide to the oxide mixoxide mix

Types of GlassTypes of Glass Tempered GlassTempered Glass

Side and rear windows of cars Side and rear windows of cars Large patio doorsLarge patio doors

Types of GlassTypes of Glass

Laminated GlassLaminated Glass Used in windshields Used in windshields

of carsof cars

Paint EvidencePaint Evidence

What is paint?What is paint? Pigments, Additives, Binders, SolventsPigments, Additives, Binders, Solvents

Is all paint alike?Is all paint alike? What about What about automobile paint?automobile paint? Electrocoat Primer Primer Surfacer Basecoat Clearcoat

Soil AnalysisSoil Analysis

Soil AnalysisSoil Analysis Microscopic ExaminationMicroscopic Examination SievingSieving Density-Gradient TubesDensity-Gradient Tubes