Soil
varies in size of component particles, the shape of particles and the
content of the particles. Sand
is composed of tiny rock crystals, but peat moss is made up vegetable
fiber. To the investigator, soil samples can place a suspect at a
crime scene or can affect the tire and footprints left behind by a
suspect. Investigators
can perform several tests on soil.
The following are several examples: porosity (how much liquid
the soil will hold), particle size (forensics can use screens to
separate different sizes of soil), pH (soil acidity), chromatography
(soil can be smeared onto a strip of filter paper and tested).
