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Science Crime Busters

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  1. Science Crime Busters Lin Wozniewski lwoz@iun.edu

  2. 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

  3. Students can bring • Spot plate or something to do reactions in • Spoon or something to get powders out • Forceps • pH paper • Magnet • Hand lens

  4. 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

  5. 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

  6. Main Focus • Chemical Analysis • Water Testing • Chromatography • Crime Scene Physical Evidence • How to prepare students • Resources

  7. 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.

  8. 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

  9. 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

  10. “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

  11. 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

  12. 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

  13. Resources • The National SO Website www.soinc.org • http://mypage.iu.edu/~lwoz/socrime/index.htm

  14. Questions? • Thank You