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

Students Bring to the Event! 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

Supervisor’s Equipment/Materials 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

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

Unknown Powders NaC 2 H 3 O 2 NaClNaHCO 3 Na 2 CO 3 LiClKCl Ca(NO 3 ) 2 CaSO 4 CaCO 3 CornstarchSucroseGlucose MgSO 4 H 3 BO 3 NH 4 Cl

NaC 2 H 3 O 2, NaCl, NaHCO 3, Na 2 CO 3, LiCl, KCl, Ca(NO 3 ) 2, CaSO 4, CaCO 3, Cornstarch, Glucose, Sucrose, MgSO 4, H 3 BO 3, NH 4 Cl CaSO 4, CaCO 3, Cornstarch NaC 2 H 3 O 2, NaCl, NaHCO 3, Na 2 CO 3, LiCl, KCl, Ca(NO 3 ) 2, Glucose, Sucrose, MgSO 4, H 3 BO 3, NH 4 Cl Add water InsolubleSoluble pH paper Strong Base Na 2 CO 3 Weak Base NaC 2 H 3 O 2, NaHCO 3 No Reaction NaCl, LiCl, KCl, Ca(NO 3 ) 2, MgSO 4, Glucose, Sucrose Acid NH 4 Cl, H 3 BO 3 NH 4 ClH 3 BO 3 Add NaOH NH 3 odorNo odor Optional

Add HCl CaCO 3 CaSO 4 Cornstarch BubblesSolution above solid clarifies Cloudy, gelatinous Flame testAdd HCl NaHCO 3 NaC 2 H 3 O 2 Na 2 CO 3 No reactionBubbles KClCa(NO 3 ) 2 LiClNaCl, MgSO 4 Glucose, Sucrose Lavender Purple OrangeRedYellowYellow, Burned

Add NaOH NaCl, Glucose, SucroseMgSO 4 Translucent precipitate No reaction Add Benedicts GlucoseNaCl, Sucrose Orange precipitate No reaction Add Hot Water NaClSucrose High solubilityLow solubility

Fiber Analysis Cotton Burn Test and lack of odor Wool Burn Test/odor of burning hair Synthetic-----Melts

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

Polymers Name Polyvinylchloride Polypropylene Polycarbonate High Density polyethylene Low Density polyethylene Polystyrene Polyethyleneterephthalate Polymethylmethacrylate Symbol Resin Code PVC3 PP5 PC7 HDPE2 LDPE4 PS6 PETE1 PMMA7

Polymers Names Polyvinylchloride Polypropylene Polycarbonate High Density polyethylene Low Density polyethylene Polystyrene Polyethyleneterephthalate Polymethylmethacrylate Densities/SP. GR All of these are #s 0.92 approximate

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

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

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

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

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

Jack Cairns CO-Director National Science Olympiad 704 N. Bradford St. Dover, DE