What are general properties of glass?
OHard solidOMade by melting sand and lime at
very high temperaturesOCan be polished, ground, or cut
once cooledOAmorphous material – Has an
irregular atomic structureOBreaks in a variety of fracture
patterns
What properties of glass allow for comparisons?
OChemical composition/properties
OShatter patternsOThicknessOColorODensityORefractive index
What is the formula for calculating density?
OD = m/VOD = Density (g/ml)Om = Mass (grams)OV = Volume (milliliters)
How is volume measured for purposes of calculating density?
OBy placing the glass fragments into a beaker filled with water and measuring the overflow in a graduated cylinder
What is the formula for Snell’s Law?
On1 (sine angle 1) = n2 (sine angle 2)On1 = 1 (refractive index of
air)OAngle 1 = Angle of incidenceOn2 = refractive index of glassOAngle 2 = Angle of refraction
What is a Becke Line and how is it interpreted?
OA halo-like effect appearing on the edge of a glass fragment when submerged in a liquid of differing refractive indexO Line inside the glass = Glass refractive
index is higher than the liquidO Line outside the glass = Glass
refractive index is lower than the liquid
What are radial fractures and how can they help determine direction of travel?
OImpact fracturesOAppear 1st
OFound on opposite side of force
OCreate straight lines that extend from the point of impact
What are concentric fractures and how can they help determine direction of
travel?
OImpact fracturesOAppear 2nd OFound on the same side as the force
OCreate circular lines around the point of impact
In reference to bullet holes, how else can direction of travel be determined?
OExamine the cone-shaped hole
OLarger side = ExitOSmaller side = EntryOAngle = Possible shooter position