Science Olympiad Forensics Event Hints Tips Things to

Science Olympiad Forensics Event Hints, Tips, Things to Prep

What’s New n n Each team member may bring notes Bunsen burner PS (polystyrene) limited to non-expanded Fingerprints q q n DNA q n 8 NCIC classifications development techniques PCR (not cell division) Blood type q q ABO avian vs mammalian vs reptilian

Overview n Story arc presents q q q suspects types of evidence which exhibit goes w/ which suspect n Table of Results q in notes? Suspects n exhibit list Evidence Powder Poly Crime Scene P 1 R 1 Suspect 1 P 2 R 3 Suspect 2 P 3 R 4 Suspect 3 P 4 R 2 Fiber Hair Gr 2

Prep the Team n n n Divide the responsibilities Trust each other Person 1 q q n start the chromatogram powder tests Person 2 q q prep the Table of Results polymers hair fibers

Make the "Notes" page n 8½" x 11 " q q q n n Table of Test Results dichotomous keys q n allowed 2 sheets this year hand written there are 2 sides to a sheet of paper… entomology flowcharts for tests q polymer density

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

Prep n Pack the "Kit" q q see list in Rules ex: thermometer n n q ex: test tubes… or any devise in which they can perform tests n n q 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 n n n plural does not specify all the same type pack plenty (include enough for cleanup)

Categories of Exemplars n n n Any 2(R), 3(S), 4(N) of Powders n fingerprints Polymers n DNA Fibers n glass Hair n entomology Chromatography n spatter n n seeds & pollen tracks & soils blood type bullet striations

Prep - Powders n Develop a Flowchart n Practice the tests q q 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 Electrolytic No Magnesium Sulfate Pos Benedict's Glucose Neg Sucrose Yes p. H mild acid faint green Flame Test Ammonium Chloride blue/green base HCl Test vinegar smell Boric Acid Sodium Acetate no smell CO 2 Test Yes <10 p. H >10 Sodium Hydrogen Carbonate Sodium Chloride No yellow/orange Calcium Nitrate red/orange Flame Test crimson purple Lithium Chloride Potassium Chloride

Prep - Polymers n 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 n Density Dichotomous Key Unknown Polymer Water floats 46% Isopropyl Alcohol sinks floats PS sinks Saturated Na. Cl sinks PETE PVC floats PC Vegetable Oil sinks floats HDPE 10% Na. Cl floats PMMA PP LDPE

Prep - Fibers n Microscopic Examination q cotton – twisted flat ribbon q wool – hair; imbricate scales

Prep - Fibers n Microscopic Examination q silk – double ribbon q linen - bamboo

Prep - Fibers n Microscopic Examination q nylon - tri-lobe cross-section q polyester - round cross-section; delustering pits

Fibers – Burn Tests Burns No Asbestos Yes No Yes Self-Extinguishing 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 n Human q q Medullary index < 1/3 even distribution of pigment Hair Cross-Section Human Hairs

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

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

Prep - Hair n Other Stuff to Know q cuticle scale patterns n n n q coronal (crown like) imbricate (flat; think shingles) spinous (petals; think asparagus tips) medulla patterns (Nationals) n n n trace discontinuous uniserial ladder multiserial ladder amorphous (bubbly)

Prep - Chromatography n n How to "run" a chromatogram How to measure Rf

Prep - Chromatography n Typical chromatograms

Prep – Mass Consider affinity Spectroscopy area under curve % concentration n n

Optional - Fingerprints n arch n tented arch n loop q q radial ulnar

Optional - Fingerprints n whorl n central pocket n double loop accidental

Optional - Fingerprints n Minutia bifurcation q trifurcation q ridge q island q dot q delta q

Optional - Fingerprints n Detection powder q cyanoacrylate fuming q n n q iodine fuming n fats, oils porous surfaces noxious, corrodes surfaces n salts n amino acids kills living tissues n n q q amino acids, fatty acids, proteins non-porous surfaces silver nitrate ninhydrin n

Optional – DNA Chromatogram • PCR – DNA copy machine

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

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

Option - Spatter n n n Directionality Angle of Impact Droplet Size

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

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

Science Olympiad Forensics Event Hints, Tips, Things to Prep