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Science Crime Busters. Lin Wozniewski lwoz@iun.edu. Safety. Students must wear: Closed shoes Slacks or skirts that come to the ankles Sleeved shirts Lab coat or lab apron Indirect vent or unvented chemical splash proof goggles. No impact glasses or visorgogs are permitted.
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Science Crime Busters Lin Wozniewski lwoz@iun.edu
Safety • Students must wear: • Closed shoes • Slacks or skirts that come to the ankles • Sleeved shirts • Lab coat or lab apron • Indirect vent or unvented chemical splash proof goggles. No impact glasses or visorgogs are permitted
Students can bring • Spot plate or something to do reactions in • Spoon or something to get powders out • Forceps • pH paper • Magnet • Hand lens
Students Can Bring • Slide & cover slip • Pencil • Paper towels • 1 sheet of paper on which anything handwritten is acceptable. • A writing instrument • Nothing else is allowed
Supervisors will provide • Unknowns • Iodine Solution • 1 M HCl • Data Collection Device w/ probes • Chromatography Materials • Wash bottle with Distilled or ROI water • Waste Container • Microscope • Other Reagents
Main Focus • Chemical Analysis • Water Testing • Chromatography • Crime Scene Physical Evidence • How to prepare students • Resources
Qualitative Analysis • Liquids, except for water and hydrogen peroxide, can be ID by either looking at them or wafting them • Metals can ID by looking at them or putting a magnet by them, or seeing how fast they react with water & HCl • Single powders (event supervisors MUST tell the students which are mixtures and how many powders are present if any have more than two) can often be ID by a quick glance, or a test or two.
Water Testing • Students might need to test for heavy metals using a calibration graph and a colorimeter. • Students might need to test for specific ions using specific ion probes (such as Ammonium, Calcium, Nitrates, etc.) • Students might be asked to test for Dissolved Oxygen using a DO probe • Students might be asked to test for turbidity using a turbidity probe. • Students might be asked to test for Total Dissolved Solids (TDS) using a conductivity probe • Students may be asked to determine if a source of pollution is from a point or non-point source
Chromatography • At this level, the students can only be asked to do paper chromatography. • Students need to know how to spot both pens and juices • Students need to know how to do both strip and sheet chromatograms. • Students need to know to mark the line to spot on and the type of material with a pencil
“Fun” Forensic Physical Crime Scene Evidence • Students need to know the basic three types of fingerprints • Students need to be able to match pretty pictures of DNA • Students need to be able to match the positive and negative shoes/footprints and Tires/Tire Tracks
How To Prepare Students • Have students develop a dichotomous key for identifying chemicals • Practice identifying chemicals in as short a time as possible. • Practice identifying powders mixed in groups of 2 & 3 • Practice testing water • Practice doing pen chromatograms • Practice doing juice chromatograms
How to Prepare Students • Practice identifying fingerprints • Practice matching DNA chromatograms/electropherograms • Practice matching shoes & tires to their tracks • Try a liquid spatter activity • Practice using a waste container
Resources • The National SO Website www.soinc.org • http://mypage.iu.edu/~lwoz/socrime/index.htm
Questions? • Thank You
