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Crime Busters

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Transcript of Crime Busters

Crime Busters
>>>
Identifying the perpetrators of a crime or crimes by using paper chromatography and analysis of unknown solids, liquids, and plastics found at the scene of a crime.
Substances to Identify
>Vitamin C
White sand, soluble, PH=2, no HCL, clears Iodine, can be tinted green,pink,orange, Distictive smell
>Flour
White powder, non-soluble, PH-7, no HCL reaction, blackens in Iodine, clumps in water.
>Gypsum
White powder, non-soluble, PH=7, no HCL or Iodine reaction, hardens in water.
Hair & Fibers
>>
The smoother the fibers the more likely they're man made.
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Most fibers are made from natural sources. Shorter fibers are twisted together with the loose ends sticking out so that it looks like fuzz.
>>
Clothing is usually mixed natural & man made fibers.
EQ: What is crime busters and what are some things that are important to the event/topic?
Crime Busters

>>
HCL (Hydraulic acid), Iodine, solubility, & PH (acidic level) are all used to identify the substances.
Fibers to Know
>
Animal Hair
-Burn Test: burns slowly & self extinguishes
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Wool
-The most commonly used animal fiber.
>
Silk
-Has been replaced by Nylon, Orlon, & Dacron.
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Cat Hair
-Finer than human hair or dog hair.
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Human Hair
-White-> has bubbles in the inner layer.
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Vegetable Fibers
-Burn Test: Ashes are fluffy, small, white-> grey colored
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Cotton
-Hairs are found on seeds of cotton plant
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Linen
-Made from the stalk of the flax plant.
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Hemp
-Excels in fiber length, strength, durability, absorbency, & antimicrobial properties.
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Synthetic Fibers
-Burn Test: Smells like burning plastic, slightly sweet.
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Rayon
-Artificial man made fibers not considered synthetic.
>
Acetate
-Created from wood.
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Nylon
-Derived from coal & non-absorbent.
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Acrylic
-Made from petroleum.
>
Spandex
-Expands to 54 times its original size.
>
Glass Fiber
-Made by stretching melted glass into fine filaments , spun into thread for weaving into cloth.
You only need to write 2.
Tracks
>>
deepness of track
tells if person was carrying
a lot of weight or not.
Polymers
Polymer~ a substance that has a molecular structure consisting chiefly or entirely of a large number of similar units bonded together, e.g., many synthetic organic materials used as plastics or resins.
Polymerization
The process of chemically bonding
monomers to make polymers.
+
+
monomers
polymers
Natural Polymers
Synthetic Polymers
~cotton
~silk
~wool
~natural rubber

~rubber
~fabrics
-Polyester, Nylon, & Rayon
~plastic
~medicine- substitutes for human tissues
Synthetic: Man Made
Vocabulary
^A.F.I.S (Automated Fingerprint Identification System):
A computer database of scanned and encoded fingerprints.
^Algor Mortis:
Measures how fast the body cools after death, which is an indicator in determining the time of death. Most accurate within 12 hrs after death but still works within 36 hrs.
^Arches:
Pattern used in identification of fingerprints. Simplest and most common type of fingerprint.
^Autopsy:
examination of dead body to find out cause & time of death. Includes thorough examination of body's injuries.
^Ballistics:
Study of effects of projectiles being fired. Involves bullets, shell casings, and firearms. Look at motion behavior, & effects of projectile after it's fired as well as residue that is present at a crime scene.
^Blood Splatter:
shape of bloodstains found at crime scenes. Help investigator determine whether or not a suspect is telling the truth and provide many clues that can help reconstruct a crime scene.
Footprint Casting
1)
Suitable casting material poured into print or track & allowed to dry
2)
Cast is removed & photographed
Individual Characteristics
cracks
shape
worn out areas
Used by comparing to suspects' shoes/vehicles
Footprint Impressions Help Identify:
- # of criminals
-points of entry/exit
-positions of suspect(s), victim(s) & witness(es)
-sequence & manner (walking, running, limping, staggering)
-Links between crime scenes; same criminals committing several crimes in one evening.
Crime Time
^Blood Typing:
test to identify type of blood in sample. A drop of blood is mixed with antibodies.
^Blowback:
the scattering of the glass pieces backwards when it is broken.
^Chain of Custody:
written record of who's handled the evidence.
^Circumstantial Evidence:
evidence that implies something but doesnt really prove it.
>Arson:
starting a fire to buildings or other property.
>Asphyxia:
depriving the body of oxygen causing either unconciousness or death. A.K.A. suffocation.
>Blind Forgery:
fake signature- suspect uses normal handwriting to sign a different name.
Paper Chromatography:
chromatography that uses selective adsorption on a strip of paper
Full transcript