soils, minerals, wood, & other vegetative matter
DESCRIPTION
Soils, Minerals, Wood, & Other Vegetative Matter. bsapp.com. Soils, Minerals, Wood, and Other Vegetative Matter. Location Link suspect Trace Evidence. bsapp.com. Soil. Any material, both natural and artificial, that lies on or near the Earth's surface - PowerPoint PPT PresentationTRANSCRIPT
Soils, Minerals, Wood, & Other Vegetative Matter
bsapp.com
Soils, Minerals, Wood, and Other Vegetative Matter.
Location Link suspectTrace Evidence
bsapp.com
SoilAny material, both natural
and artificial, that lies on or near the Earth's surface
Most of this evidence is only useful as support or lead generating
bsapp.com
Examination of SoilThroughout the examination of soil an observer must:
Look for trace evidenceCompare the physical and chemical properties of each sample to a control sample
bsapp.com
Components in soil
Breakdown of soil
Clay Sand Silt
Loam is a mixture of all parts
What's your type?Squeeze some soil between your fingers. Is it crumbly? Sticky? A soil's texture depends on the size of its particles. And living things depend on the right texture to thrive in the soil.
Soil Textures
Soil Particles Gravel:larger than 2mm; feels coarseSand:2 - 0.05mm; feels grittySilt:0.05 - 0.002mm; feels like flourClay:smaller than 0.002; feels sticky when wet
Let’s look at certain areas
ftp://ftp-fc.sc.egov.usda.gov/NSSC/StateSoil_Profiles/tx_soil.pdf ftp://ftp-fc.sc.egov.usda.gov/NSSC/StateSoil_Profiles/la_soil.pdf ftp://ftp-fc.sc.egov.usda.gov/NSSC/StateSoil_Profiles/ok_soil.pdf ftp://ftp-fc.sc.egov.usda.gov/NSSC/StateSoil_Profiles/fl_soil.pdf ftp://ftp-fc.sc.egov.usda.gov/NSSC/StateSoil_Profiles/il_soil.pdf ftp://ftp-fc.sc.egov.usda.gov/NSSC/StateSoil_Profiles/ak_soil.pdf
Original site:http://soils.usda.gov/gallery/state_soils/
12 Orders/Categories of Soil
Matching Soil Samples
Two samples are considered to be the same if and only if they match on each and every level of the following tests
bsapp.com
Keep in mind…
Dirt changes shade and color at different moisture levels
Dried dirt may clot
bsapp.com
Gross Examination
1. Color2. Texture3. Shapes4. Foreign Objects
bsapp.com
UV-Observations Note the shape, size, number, and
identity (if possible) of any material that fluoresces
Compare samples to known dirt from an area
bsapp.com
Review: Electromagnetic Spectrum
A phosphor material converts the energy in the UV radiation from a black light into visible light.
UVA = black lightUVB= harmful rays (skin cancer)
FACT: a persons skin will tan with AVA and sunburn with UVB…
so what times of the day does the sun emit UVB?
Florescence
Bathroom tile as viewed with the visible light spectrum
Now: viewed using UV light (black light)
Materials that are fluorescent:
Semen Blood Urine Vitamins Antifreeze Chlorophyll Minerals in rocks Scorpion exoskeleton
Panties stained with semen
Blood appears dark under UV light because it will absorb all of the spectrum
Urine in toilet is glowing
BAD kitty!
Antifreeze under black light-helps to detect leaks-used to recreate crash scenes
Hope Diamond
Light spectrum
Hope Diamond
UV Light
bsapp.com
bsapp.com
The clothes of this female look
normal.
Any chemicals?
bsapp.com
bsapp.com
bsapp.com
bsapp.com
bsapp.com
bsapp.com
bsapp.com
A UV-Light may also be used to find trace evidence on a body
bsapp.com
bsapp.com
Microscopic Observation
ColorTextureShapesForeign Objects
bsapp.com
Place a thin layer of dirt on a slide
bsapp.com
Place only a small amount of sample on the slide at a
time. Be sure the dirt is placed only in the center of the slide so as not to
allow it to fall in the microscope.
WARNING
bsapp.com
Place a second slide on top of the sample
bsapp.com
Naked Eye
bsapp.com
Microscopic x10
bsapp.com
Microscopic x40 (Cotton Fiber)
bsapp.com
Final Comparison Any and all foreign objects found
should be investigated separately If all previous comparisons are
similar between two samples they likely originate from the same area
As final comparison density gradient columns may be utilized
bsapp.com
Density Gradient Tubes
Assemble two identical density columns with varying levels of liquids in them
Drop equal amounts of soil samples (a control and unknown) in the columns
Allow the samples to disperse throughout the columns for comparison
If the two samples are of the same origin, then they will produce nearly identical gradient tubes
bsapp.com
bsapp.com
bsapp.com