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Science Olympiad Forensics Event
Hints, Tips, Things to Prep
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What’s New Each team member may bring notes Bunsen burner
PS (polystyrene) limited to non-expanded Fingerprints 8 NCIC classifications development techniques DNA PCR (not cell division) Blood type ABO avian vs mammalian vs reptilian
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Overview Story arc presents Table of Results suspects
types of evidence which exhibit goes w/ which suspect exhibit list Table of Results in notes? Evidence Powder Poly Fiber Hair Gr 2 Gr 2 Crime Scene P1 P2 P3 P4 R1 R3 R4 R2 Suspect 1 Suspects Suspect 2 Suspect 3
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Prep the Team Divide the responsibilities Trust each other Person 1
start the chromatogram powder tests Person 2 prep the Table of Results polymers hair fibers
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Make the "Notes" page 8½" x 11 " Table of Test Results
allowed 2 sheets this year hand written there are 2 sides to a sheet of paper… Table of Test Results dichotomous keys entomology flowcharts for tests polymer density
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Make the "Notes" page tables of expected results
powders which test yields which positive indication distinguishing characteristics hair fibers glass formulas Rf spatter
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Prep Pack the "Kit" see list in Rules ex: thermometer
non-mercury (safety clause) does not specify analog or digital ex: test tubes… or any devise in which they can perform tests plural test tubes spot plates, well plates have enough to run all tests w/o washing waterproof box for dirty stuff ex: paper towels does not specify all the same type pack plenty (include enough for cleanup) Read the rules… singular vs plural build the kit while practicing the tests
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Categories of Exemplars
Powders Polymers Fibers Hair Chromatography Any 2(R), 3(S), 4(N) of fingerprints DNA glass entomology spatter seeds & pollen tracks & soils blood type bullet striations Required Groups - 55% Optional Groups – 15% Analysis – 30%
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Prep - Powders Develop a Flowchart Practice the tests
chart of results in "Notes" count equipment needed for "Kit"
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Soluble Iodine Test HCl Test Flame Test Electrolytic Benedict's pH
No Pos Cornstarch Soluble Iodine Test Pos Calcium Carbonate HCl Test yellow Calcium Sulfate Yes Flame Test no effect Magnesium Sulfate No Pos Glucose Electrolytic Benedict's Neg Sucrose Yes mild acid faint green Ammonium Chloride pH Flame Test blue/green Boric Acid base vinegar smell Sodium Acetate HCl Test no smell Yes <10 Sodium Hydrogen Carbonate CO2 Test pH >10 Sodium Carbonate Sodium Chloride No yellow/orange Calcium Nitrate red/orange Lithium Chloride Flame Test crimson purple Potassium Chloride
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Prep - Polymers Burn Test Results Polymer "Burn" Behavior PETE
Bubbles; slow burn; soot; pungent HDPE Fast burn; clean; drips flames; white smoke LDPE PS Fast burn; lots of black soot PP Slow burn; some drips flame PVC Melts more than burns; self-extinguishing PMMA Bright flame; no smoke PC Slow burn / smolder; no smell; self-extinguishing
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Prep - Polymers Density Dichotomous Key Water 46% Isopropyl Alcohol
Vegetable Oil 10% NaCl Saturated NaCl PP LDPE HDPE PS PETE PVC PC PMMA Unknown Polymer floats sinks
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Prep - Fibers Microscopic Examination cotton – twisted flat ribbon
wool – hair; imbricate scales
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Prep - Fibers Microscopic Examination silk – double ribbon
linen - bamboo
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Prep - Fibers Microscopic Examination nylon - tri-lobe cross-section
polyester - round cross-section; delustering pits
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Fibers – Burn Tests Burns Asbestos Self-Extinguishing Chars Melts
No Self-Extinguishing Yes Chars Burning Grass Grey Ash Linen Melts Burning Paper Cotton Vinegar Odor Hard Black Ash Acetate Burning Meat Rayon Tumeric Odor Soft Black Ash Acrylic Burning Hair Soft Black Bead Silk Dark Ash Wool Celery Odor Hard Grey Bead Nylon Sweet Smell Hard Black Bead Polyester
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Prep - Hair Human Medullary index < 1/3
even distribution of pigment Hair Cross-Section Human Hairs
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Prep - Hair Animal Medullary index > 1/2 Dog continuous medulla
scales usually not visible ovoid bodies root is spade-like
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Prep - Hair Animal Medullary index > 1/2 Cat
uniserial medulla; very large spinous scales root looks frayed
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Prep - Hair Other Stuff to Know cuticle scale patterns
coronal (crown like) imbricate (flat; think shingles) spinous (petals; think asparagus tips) medulla patterns (Nationals) trace discontinuous continuous uniserial ladder multiserial ladder amorphous (bubbly)
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Prep - Chromatography How to "run" a chromatogram How to measure Rf
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Prep - Chromatography Typical chromatograms
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Prep – Mass Spectroscopy
Consider affinity area under curve % concentration
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Optional - Fingerprints
arch tented loop radial ulnar
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Optional - Fingerprints
whorl central pocket double loop accidental
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Optional - Fingerprints
Minutia bifurcation trifurcation ridge island dot delta
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Optional - Fingerprints
Detection powder cyanoacrylate fuming amino acids, fatty acids, proteins non-porous surfaces iodine fuming fats, oils porous surfaces noxious, corrodes surfaces silver nitrate salts ninhydrin amino acids kills living tissues
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Optional – DNA Chromatogram
PCR – DNA copy machine
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Option - Glass Index of Refraction Hot-Stage Microscope Stress Lines
Order of fractures
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Option - Entomology Time Lines Blow Fly Beetles larva maggot pupa
adult Beetles usually arrive after blow flies
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Option - Spatter Directionality Angle of Impact Droplet Size
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Option – Seeds, pollen Option – Tracks Option – Soils
visual microscopic comparison Option – Tracks visual comparisons directionality Option – Soils compare composition microscopic examination soil triangle
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Option – Blood Type Option – Bullets ABO blood type
perform antigen tests RBC, WBC, platlet human vs avian vs reptilian Option – Bullets comparison of striations
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Science Olympiad Forensics Event
Hints, Tips, Things to Prep
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