Transcript Chapter 4.3
Characteristics of Soil
Pg. 111-115
List
the important forensics
properties of soil
Describe proper collection of
soil evidence
any disintegrated surface
material, both natural and
artificial, that lies on or near the
earth’s surface.
Naturally
occurring rocks,
minerals, vegetation, animal
matter
Manufactured objects
1.
2.
prevalence at a crime
scene
transferability between
the scene and the
criminal
gross appearance
a.
b.
c.
d.
color (dried), texture
plant and animal materials
artificial debris
minerals and rocks present
naturally
occurring crystal,
approx. 2200 but only 40 are
most common
Rocks are characterized by
mineral content and grain
size
1.
Used to compare soil specimens
This test is useful when used in
combination of other tests
Fill a tube with liquids of different
densities
•
2.
3.
Layer on bottom is most dense, each
subsequent layer is of decreasing density
Add soil samples
Particles of same density will be
suspended in the match point density
Standard/reference soils collected at
various intervals within 100 yd radius
Samples collected at the alibi locations
Need 1-2 T of soil for a sample
Specimens packaged in individual
containers
Objects with soil are collected
Samples of soil are collected under car
fenders and frame
1.
2.
3.
4.
5.
6.
•
need to keep in lump form