1. Science Crime Busters
Division B

2. Sr. Research Biochemist University of Illinois
Andy Shaw
Sr. Research Biochemist
Merck & Co.
West Point, PA
Ph.D. in Chemistry
University of Illinois
7 years involvement with Science Olympiad
5 years State Event Supervisor
3 years Regional Event Supervisor
2005 National Event Supervisor
2006 Coaches Clinic Presenter

3. Event Parameters
A team of 2 students competes for 50 minutes to analyze crime scene evidence and write a summary of their analysis
Scoring:
Qualitative analysis: 50%
Physical evidence: 25%
Essay of the analysis: 25%

4. Rule Changes
Cheat Sheet!! – Students may bring handwritten notes on both sides of a 8.5 x 11 sheet of paper
Supervisors will not provide a list of unknowns
Changes to number of unknowns
Changes to polymers tested
Multiple pieces of physical evidence (fingerprints, DNA, shoe prints, tire treads, and spatters) will be tested

5. General Safety Precautions
Safety! Safety! Safety! Safety! Safety!
Bring and wear lab coat/apron that cover the knees, OSHA approved indirectly vented splash goggles (over the eyes), pants/skirt that cover the legs to the ankles (no shorts)
No open toed shoes
No tasting or touching chemicals

6. Equipment Provided by Student
Small containers/reaction plates
Wood splints or plastic spoons
pH paper
Forceps and microscope slides
Magnet
Hand lens
Paper towels
Pencils
NO CALCULATORS

7. Equipment Provided by Supervisor
Iodine solution
1 M HCl
Paper chromatography materials
chamber, solvent, paperclips, etc.
Waste container
Distilled water
Liquids for density test of polymers

8. Unknown Analysis Identify metals, liquids, and powders
Students should be familiar with common uses for each compound
Students should develop a strategy for identification (see flow charts)
Some mixtures of powders may be given

9. Liquid Identification
Observation
Odor
React w/I2 pH
Water
Colorless, Clear
None ~6
Ammonia
Cloudy, especially after shaking
Sharp, strong
~10
Hydrogen Peroxide
Colorless, Clear, Bubbles when shaken
Bubbles
Lemon Juice
Cloudy, yellowish
Light ~2
Rubbing Alcohol
Sweet
Vinegar
Strong
Bleach
Slightly Yellowish
Clears color
We will be looking at how you would test liquids. Although we are only going to look at six common liquids you might expect to find around the house, the methods for identifying the liquids are similar. The five liquids we will be learning to identify are water, vinegar, lemon juice, hydrogen peroxide ammonia, and rubbing alcohol.
The first test we will do is a simple matter of observing the solutions. Some of the solutions will all look the same at first. But if you look close you will notice a difference. Shake all of the liquid vials and see what happens.
The second test we will do is smell. This is an easy test and is one of the best at identifying the unknowns. But it is not as easy as it sounds. One thing a scientist does not want to do is put a chemical right under their nose and inhale. This is very dangerous. If the chemical is concentrated or a health hazard this can make you very sick or very dead. Therefore, what we do is hold the chemical container out in front of our faces by a few inches. Then we bring a hand toward our nose passing the hand over the top of the open container of the liquid. This will bring just enough of the vapors of the liquid to our noses to smell.
The last test we will do is to test the pH of the liquids. We do this by dipping the glass-stirring rod in the liquid and then touching the rod to a piece of pH paper. We then compare the color against the chart on the side of the vial the pH paper was in.
Here is a chart similar to the one you will fill out. Do your findings agree?

10. Liquid Identification Flow ChartNo
Yes
Cloudy?
pH~10?
Ammonia
pH~2?
Lemon Juice
Odor?
Rubbing Alcohol
Vinegar
Bubbles when shaken?
Hydrogen Peroxide
Water
Bleach
Sweet?
Most of the liquids are fairly straight forward to identify. But students should not get in the habit of using the process of elimination as a method of analyzing the liquids. On most of my crime scenes the same liquid is used more than once. It may be found at the crime scene and on one or more of the suspects. Students are then expected to use this evidence as a way of implicating or not implicating the suspect.
The most difficult identification is water or hydrogen peroxide. Hydrogen peroxide naturally decomposes into oxygen and water. It is easy to tell fresh hydrogen peroxide because if the vial or bottle is shaken, the decomposition reaction will be accelerated and the bubbles of oxygen will be easily seen. The spontaneous decomposition oxygen bubbles of older hydrogen peroxide will not be as easy to see. If the suspected hydrogen peroxide is mixed with the Iodine solution, the decomposition reaction will be catalyzed and the bubbles will be seen. If the hydrogen peroxide is even older, this may not work. If yeast is one of the powder unknowns, then the yeast can be mixed with the suspected hydrogen peroxide. The yeast will again catalyze the decomposition reaction. If the hydrogen peroxide is so old that all of the hydrogen peroxide has spontaneously decomposed, it is water, not hydrogen peroxide!

11. Metal Identification Metal Observations Mag- netic? Water HCl Aluminum
Gray, Dull, sometimes shiny No
No Reaction
Delayed reaction
Copper
Yellow or Brownish
Iron
Dark
Yes
Magnesium
Dull, Light metal
Delayed Tiny bubbles
Immediate violent reaction
Tin
Yellowish tinge
Little if any reaction
Zinc
Shiny, dense (heavy) metal no
Just as one can identify a liquid by it’s properties, one can also identify a metal by how it behaves. Of course we can not really use smell as a method of identification with a metal, but instead we can use how it reacts with other substances. We can not look at all of the metals. There just is not time. Forensic scientists may use many of these same techniques when they have to identify a metal found on a victim or a suspect. Many times they use these techniques in cases of hit and run drivers. Forensic scientists also have more sophisticated techniques available to be sure they have correctly identified the metal. Some metals are alloys, which means that they were melted to their liquid state and then two or more different metals were mixed together. When the alloy cools, it is actually a metal that has some of the properties of all the metals that were mixed together to make up the alloy. The properties of the alloy will be different depending on the proportions of the various metals mixed. Then it is important to find out, not only what the metal is, but the proportions of the metals that made up the alloy. Unfortunately this is very time consuming and we just do not have the time to do it.

12. Metal Identification Flow ChartNo
Yes
Very tiny bubbles
Magnetic?
Iron or an Iron Alloy
React w/water?
Magnesium
React w/acid?
Fast?
Zinc
Tin or a Tin Alloy
Aluminum
Yellowish?
Copper or a Copper Alloy

13. Qualitative Analysis Flow Chart

14. Qualitative Analysis Flow Chart

15. Polymers Name Densities/SP. GR. Polyvinylchloride 1.38 Polypropylene
Polycarbonate
High Density polyethylene
Low Density polyethylene
Polystyrene
Polyethyleneterephthalate
Polymethylmethacrylate
Densities/SP. GR.
1.38
0.90
1.20
0.95
0.92
1.05
1.37
1.16
Values are approximate

16. Densities of Common Solvents
Water
10% Salt Water
20% “ “
25% “ “
Saturated NaCl
50% Ethanol/water
70% Isopropanol
Mazola Oil
1.0g/ml
1.07
1.15
1.19
1.36
0.94
0.93
0.918
Source: Handbook of Chemistry and Physics

17. Chromatography Chromatography results may vary depending on solvent
For example, isopropanol vs. water
If solvent is provided, use it
Chromatography samples generally run slow and need to be run longer than students think (15-20 minutes)
Ink samples spotted on filter paper
Isopropanol as solvent
Suspects 3 & 6 computer ink matches computer printout found at scene

18. Fingerprint Analysis
At the Division B level, students are expected to match fingerprints, not to use whorl, loop, arch terminology or explain how prints are obtained

19. DNA Analysis
At the Division B level, students are expected to match the patterns of bands on a gel that simulates DNA sequencing

20. Hair Analysis
Taken from Science Olympiad website (on last slide).

21. At the Division B level, students are expected to match the prints
Boot Print Analysis
At the Division B level, students are expected to match the prints

22. X = implicated by evidence
Analysis of the Crime
What does each piece of evidence mean by itself?
How does all the evidence fit together?
Make a table:
Steven
Michael
Daniel
Josephine
Robert
Genevieve
Unknowns X
Chromato-graphy
DNA
Prints
X = implicated by evidence

23. Tips from the Supervisor
“A good note sheet is key”
Have a list of chemical reactions, fiber analysis, types of fingerprints, etc.
Time is a factor: 33% of teams finshed at regional, 10% finished at state
Students did best on the powder and fingerprint tests, and struggled on polymer and fiber analysis.
Practice running chromatography

24. Additional Resources
Visit the Science Crime Busters webpage at the Science Olympiad website:
This has many links to resources that are helpful in preparing for the event.
It also has links to places you can order fiber and polymer kits.