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