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Forensics 2006

Ensure safety in the forensics lab by wearing a lab coat, safety goggles, and proper attire. Follow guidelines for handling chemicals and utilize necessary equipment.

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Forensics 2006

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  1. Forensics2006

  2. Forensics and Safety • Safety! Safety! Safety! Safety! Safety! • Bring and wear lab coat/apron that cover the knees, OSHA approved indirectly vented splash goggles, pants/skirt that cover the legs to the ankles • No open toed shoes • No tasting or touching chemicals

  3. Test tubes/holder Droppers Funnels Filter Paper pH Paper Spatulas Stirring Rods Thermometer 9 Volt Conductivity Tester Flame Test Equipment E.g. flame spreader, nichrome wire Cobalt Blue Glass plate Metal Tongs Slides Students Bring to the Event!

  4. Lugol’s Solution 2M HCl 2M NaOH Benedict’s Solution Hot Water Bath Heat Source-Flame Testing Distilled Water Matches and Candle for Fabric Burn Tests A method that will permit differential density tests Candle/Matches for fiber burn tests Other Equipment that they choose to provide Supervisor’s Provides:

  5. The Competition • Qualitative Analysis of up to 5(R), 8(S/N) powders • Polymer testing of up to 3(R), 4(S), 5(N) • Fiber analysis of (2), 3(S), 4(N) • Hair samples of 2 (R), 3(S), 4(N) • Chromatography including IR. UV, & GC Spectrophotography • Serology of blood samples • Fingerprint Analysis • Analysis of the Crime

  6. Unknown Powders

  7. NaC2H3O2, NaCl, NaHCO3, Na2CO3, LiCl, KCl, Ca(NO3)2, CaSO4, CaCO3, Cornstarch, Glucose, Sucrose, MgSO4, H3BO3, NH4Cl Add water CaSO4, CaCO3, Cornstarch NaC2H3O2, NaCl, NaHCO3, Na2CO3, LiCl, KCl, Ca(NO3)2, Glucose, Sucrose, MgSO4, H3BO3, NH4Cl Insoluble Soluble pH paper AcidNH4Cl, H3BO3 Strong BaseNa2CO3 Weak BaseNaC2H3O2, NaHCO3 No ReactionNaCl, LiCl, KCl, Ca(NO3)2, MgSO4, Glucose, Sucrose Add NaOH Optional NH4Cl H3BO3 NH3 odor No odor

  8. Add HCl Add HCl Flame test CaCO3 CaSO4 Cornstarch Bubbles Solution above solid clarifies Cloudy, gelatinous NaHCO3 NaC2H3O2 Na2CO3 Bubbles No reaction Bubbles KCl Ca(NO3)2 LiCl NaCl, MgSO4 Glucose, Sucrose Lavender Purple Orange Red Yellow Yellow, Burned

  9. Add NaOH MgSO4 NaCl, Glucose, Sucrose Translucent precipitate No reaction Add Benedicts NaCl, Sucrose Glucose No reaction Orange precipitate Add Hot Water NaCl Sucrose Low solubility High solubility

  10. Polyethylene terphthalate High Density Polyethylene Polystyrene Low Density Polyethylene Polyvinyl Chloride Polypropylene Polymethyl-methacrylate Polycarbonate Unknown Polymers

  11. Name Polyvinylchloride Polypropylene Polycarbonate High Density polyethylene Low Density polyethylene Polystyrene Polyethyleneterephthalate Polymethylmethacrylate Symbol Resin Code PVC 3 PP 5 PC 7 HDPE 2 LDPE 4 PS 6 PETE 1 PMMA 7 Polymers

  12. Names Polyvinylchloride Polypropylene Polycarbonate High Density polyethylene Low Density polyethylene Polystyrene Polyethyleneterephthalate Polymethylmethacrylate Densities/SP. GR. 1.38 0.90 1.20 0.95 All of these are #s 0.92 approximate. 1.05 1.37 1.16 Polymers

  13. Water 10% Salt Water 20% “ “ 25% “ “ Saturated NaCl 50% Ethanol/water 70% Isopropanol Mazola Oil 1.0g/ml 1.07 1.15 1.19 Handbook of 1.36 Chemistry and 0.94 Physics 0.93 0.918 Densities of Common Solvents

  14. Polymer Scheme Unknown Polymers floats Add to water—Sp. Gr. 1.0 Add 46% Isopropanol—Sp. Gr. 0.94 floats sinks floats Add to Vegetable Oil—Sp. Gr. 0.92 Add to 10% NaCl solution—Sp.Gr. 1.07 sinks floats PP sinks PS HDPE LDPE Cont’d next page

  15. Polymer Scheme (contd.) Add to 10% NaCl solution—Sp.Gr. 1.07 sinks Add to saturated NaCl—Sp. Gr. 1.36 floats Add to 25% NaCl Sp. Gr. 1.19 floats sinks sinks PC PMMA PETE Burn test result- yellow flame PVC Burn test result- green flame

  16. Fiber Analysis Fabrics • Cotton----------------Burn Test,ash & lack of odor • Silk-------------------Burn Test & ash • Wool-----------------Burn Test/odor of burning hair • Nylon----------------Burn Test-melts first, heavy black smoke • Spandex ------------Same as nylon, but very elastic when pulled

  17. Hair Analysis • Human Medulla is fragmented if any at all Medulla index is less than 1/3 • Cat Medulla is interrupted Medulla index is ½ or greater • Dog Medulla is continuous Medulla index is ½ or greater Medulla Index = Diameter-medulla/ Diameter-hair shaft

  18. Hair Components • Hair Sample hair shaft medulla-continuous Medulla-fragmented

  19. Serology or Blood Testingbased upon slides, photographs, or simple chemical tests Human Blood has many chemical species in the fluid, but for the purpose of this activity only the following antibodies are important: A, B, AB, and O!

  20. Chromatography andSpectrophotometry Students need to: • Separate components of a mixture using PaperChromatography • Analyze, only gas chromatograms, UV and IR Spectrophotometry

  21. Fingerprints • Plain Arch • Tented Arch • Radial Loop • Ulnar Loop • Central Pocket Loop • Double Loop • Whorl • Accidential

  22. Definitions • Core-center or focal point of the print • Bifurcate-the splitting of a ridge into two. • Delta-another center or focal point of the fingerprint • Ridge count-number of ridges that either cross or touch an imaginary line usually connecting the core and delta

  23. Jack CairnsCO-Director National Science Olympiad Jcairnsc@aol.com 704 N. Bradford St. Dover, DE 19904

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