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Forensics

Forensics . 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.

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Forensics

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  1. Forensics

  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 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 Various Solutions that can be used for density testing with polymers e.g. saltwater, alcohol, corn oil, or other similar materials Other Equipment that they choose to give Supervisor’s Equipment/Materials

  5. The Competition • Qualitative Analysis of up to 6 powders • Polymer testing of up to 4 polymers • Fiber analysis • Chromatography including IR. UV, & GC Spectrophotometry • 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. Fiber Analysis • Cotton---------Burn Test and lack of odor • Wool----------Burn Test/odor of burning hair • Synthetic-----Melts

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

  12. 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

  13. 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

  14. 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

  15. 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

  16. 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

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

  18. 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

  19. Jack CairnsCO-Director National Science Olympiad Jcairnsc@aol.com 704 N. Bradford St. Dover, DE 19904 302-734-4600

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