Presentation on theme: "Lin Wozniewski firstname.lastname@example.org Crime Busters Lin Wozniewski email@example.com."— Presentation transcript:
1 Lin Wozniewski firstname.lastname@example.org Crime BustersLin Wozniewski
2 DisclaimerThis presentation was prepared using draft rules. There may be some changes in the final copy of the rules. The rules which will be in your Coaches Manual and Student Manuals will be the official rules
3 Safety Students must wear: Closed shoes Slacks or skirts that come to the anklesLab coat or lab apronIndirect vent or unvented chemical splash proof goggles. No impact glasses or visorgogs are permittedLong-Sleeved Shirt (if wearing a lab apron)Gloves are encouraged
4 Students can bringSpot plate, test tubes & rack, beakers, or something to do reactions inSpoon or something to get powders outForcepspH paperMagnetHand lens
5 Students Can Bring Something to stir the reagents Slide & cover slip PencilPaper towels1page of notes from any sourceA test tube brushA writing instrumentNothing else is allowed
6 Supervisors will provide UnknownsIodine Solution1 M HClDifferential Density materialsChromatography MaterialsWash bottle with Distilled or ROI waterCandle and matchesWaste Container
7 Supervisors may Provide MicroscopeOther reagents
8 Crime Scene Physical Evidence How to prepare students Resources Main FocusChemical AnalysisPolymersChromatographyCrime Scene Physical EvidenceHow to prepare studentsResources
9 How To Prepare Students Have students develop a dichotomous key for identifying chemicalsPractice identifying chemicals in as short a time as possible.Practice identifying powders mixed in groups of 2 & 3Practice identifying plasticsPractice identifying hairs (only human, dog, cat possible)Practice identifying fibers (only animal, vegetable, & synthetic possible)
10 How to Prepare Students Practice doing pen chromatogramsPractice doing juice chromatogramsPractice identifying fingerprintsPractice matching DNA chromatograms/electropherogramsTry a liquid Practice matching shoes & tires to their tracksspatter activityPractice using a waste container
11 Resources The National SO Website www.soinc.org To prepare students For Event SupervisorsFor Lesson Plans to use in the classroom
13 Time to PlayI have a crime for you to solve if you want to get your hands wet so that you will know what you are doing with your studentsI am prepared to show you how to do any of the tests with either knowns or unknownsWhat do you want to do? Some can work & I will help while others may have specific requests of me
14 Crime Let’s solve the crime Step one – read over crime Best to divide and conquerOne partner starts on chromatographyOne partner starts on Qualitative AnalysisPartner finishes chromatography & starts polymersShould finish in about 30 minutes and have remaining time to analyze.
15 Chromatography Used to separate mixtures into components Uses stationary (paper) and mobile (water) phasesDepends on affinity of molecules for the 2 phases for how fast molecule movesStrip or SheetDraw a line ~ 2 cm from bottom in pencilSpot on line. Use toothpick for liquids.Use pencil to label at top above spot.Put bottom only of paper in waterWait until water moves up ~ 3/4ths of paper.
16 Powder AnalysisNeed well thought out and practiced dichotomous scheme.Let’s go through our powder
17 Mixed Powder Analysis Can have 2 or 3 of the “*” powders mixed. Students have to be told which powders are mixed and how many powders are mixed.Lets try our mixed powder and see what is in it using the dichotomous key
19 Liquid Analysis Also need practiced dichotomous scheme Lets see what our liquid is
20 Metal Analysis Again need practiced dichotomous scheme Let us see what our metal is
21 Plastics A good dichotomous scheme needed here too. So what is our plastic?
22 Fiber AnalysisOnly need to know the difference between animal, vegetable, and synthetic fibersEasiest to identify with burn testAnimal shrivel in heatVegetable burnSynthetic melt.So what is our fiber?
23 Hair Analysis Only allowed to use Human, Dog, and Cat Best identified by looking at microscope.Human hair thickest, no distinct cuticleCat hair thinnest, distinct palm tree or braided cuticle.Dog hair in between thickness and in between cuticle.What type of hair was found at scene?
24 Soil Analysis Sand, Silt, Clay, and Loam Students allowed to touch soil to analyzeSand-large grains, does not ball in handClay-very small grains, forms ribbons in fingersSilt-medium grains, forms ball, but falls apartLoam-lots of organic material, blackWhat type of soil was found at scene?
25 Fingerprints Only need to know Whorl, Loop, and Arch Arch- hill-no deltasLoop – around the lake -1 deltaWhorl-target-2 deltasWhat type of fingerprint?
26 DNA Pretty picture matching Easy to make electropherograms Make rectangle with drawing programUse spray tool to spray in different width, density lines at various distances.
27 Tracks More pretty picture matching, but inverses. Bike tracks easy to get at a bike rodeoHave cookie sheet filled with sand,Take a picture of tire, run through sand, and take a picture of track.For footprints photo bottom of shoeStomp in cookie sheet of flourStomp onb lack construction paperPhotograph paper
28 Spatters NOT MEASURING ANGLES Should know if strait drop or angle Should know if spatter is high or lowI start with red finger paint, then mix in blue and green until correct shadeThen I dilute with water slowly until proper consistency.Students should put in eye dropper or use paint brush and drop straight 1 cm, 10 cm. 20 cm, etc.
29 Solve CrimeNow we will put all of the evidence together to solve the crime.It is the preponderance of evidence that is being looked forPlease remember that the perpetrator may be one of the suspects, more than one suspect, all of the suspects, or none of the suspects.