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Science Olympiad Forensics Event Hints, Tips, Things to Prep.

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Presentation on theme: "Science Olympiad Forensics Event Hints, Tips, Things to Prep."— Presentation transcript:

1 Science Olympiad Forensics Event Hints, Tips, Things to Prep

2 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

3 Overview Story arc presents  suspects  types of evidence  which exhibit goes w/ which suspect exhibit list Table of Results  in notes? Crime Scene Suspect 1 Suspect 2 Suspect 3 Suspects Evidence PowderFiberHairPolyGr 2 P1 P2 P3 P4 R1 R3 R4 R2

4 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

5 Make the "Notes" page 8½" x 11 "  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

6 Make the "Notes" page tables of expected results  powders which test yields which positive indication distinguishing characteristics  hair  fibers  glass formulas RfRf  spatter

7 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 plural does not specify all the same type pack plenty (include enough for cleanup)

8 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

9 Prep - Powders Develop a Flowchart Practice the tests  chart of results in "Notes"  count equipment needed for "Kit"

10 SolubleIodine Test HCl Test Flame Test Cornstarch Calcium Carbonate Calcium Sulfate Pos Electrolytic Yes Benedict's No Glucose Sucrose Neg NoPos pH mild acid Ammonium Chloride Yes HCl Test vinegar smell Sodium Acetate base CO 2 Test no smell pH <10 Sodium Hydrogen Carbonate Sodium Carbonate >10 Yes Sodium Chloride Calcium Nitrate Lithium Chloride Potassium Chloride yellow/orange red/orange crimson purple Flame Test No Magnesium Sulfate yellow no effect Boric Acid Flame Test faint green blue/green

11 Prep - Polymers Burn Test Results Polymer"Burn" Behavior PETEBubbles; slow burn; soot; pungent HDPEFast burn; clean; drips flames; white smoke LDPEFast burn; clean; drips flames; white smoke PSFast burn; lots of black soot PPSlow burn; some drips flame PVCMelts more than burns; self-extinguishing PMMABright flame; no smoke PCSlow burn / smolder; no smell; self-extinguishing

12 Prep - Polymers Density Dichotomous Key Water 46% Isopropyl Alcohol Vegetable Oil 10% NaCl Saturated NaCl PPLDPEHDPE PS PETEPVC PCPMMA Unknown Polymer floats sinks floats sinks floats sinks floats

13 Prep - Fibers Microscopic Examination  cotton – twisted flat ribbon  wool – hair; imbricate scales

14 Prep - Fibers Microscopic Examination  silk – double ribbon  linen - bamboo

15 Prep - Fibers Microscopic Examination  nylon - tri-lobe cross-section  polyester - round cross-section; delustering pits

16 Fibers – Burn Tests Burns Asbestos No Self-Extinguishing Yes Chars NoYes Burning Grass Grey Ash Linen Melts Burning Paper Grey Ash Cotton Vinegar Odor Hard Black Ash Acetate Burning Meat Hard Black Ash Rayon Tumeric Odor Soft Black Ash Acrylic Chars Burning Hair Soft Black Bead Silk Melts Burning Hair Dark Ash Wool Celery Odor Hard Grey Bead Nylon Sweet Smell Hard Black Bead Polyester

17 Prep - Hair Human  Medullary index < 1/3  even distribution of pigment Human Hairs Hair Cross-Section

18 Prep - Hair Animal  Medullary index > 1/2  Dog continuous medulla scales usually not visible ovoid bodies root is spade-like

19 Prep - Hair Animal  Medullary index > 1/2  Cat uniserial medulla; very large spinous scales root looks frayed

20 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)

21 Prep - Chromatography How to "run" a chromatogram How to measure R f

22 Prep - Chromatography Typical chromatograms

23 Prep – Mass Spectroscopy Consider affinity area under curve  % concentration

24 Optional - Fingerprints arch tented arch loop  radial  ulnar

25 Optional - Fingerprints whorl central pocket double loop accidental

26 Optional - Fingerprints Minutia  bifurcation  trifurcation  ridge  island  dot  delta

27 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

28 Optional – DNA Chromatogram PCR – DNA copy machine

29 Option - Glass Index of Refraction Hot-Stage Microscope Stress Lines Order of fractures

30 Option - Entomology Time Lines Blow Fly  larva  maggot  pupa  adult Beetles  usually arrive after blow flies

31 Option - Spatter Directionality Angle of Impact Droplet Size

32 Option – Seeds, pollen visual microscopic comparison Option – Tracks visual comparisons directionality Option – Soils compare composition microscopic examination soil triangle

33 Option – Blood Type ABO blood type  perform antigen tests  RBC, WBC, platlet  human vs avian vs reptilian Option – Bullets comparison of striations

34 Science Olympiad Forensics Event Hints, Tips, Things to Prep


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