Forensics

Forensics is a Division C chemistry event that involves identification of powders, polymers, fibers, and hair samples, blood serum and fingerprint analysis, and interpretation of chromatography. Given a scenario and some possible suspects, students will perform a series of tests. These tests, along with other evidence or test results will be used to solve a crime. This event is closely associated with the Division B event, Crime Busters.

Equipment
1 or 2 people per team. Eye protection #4. 50 minutes.

Students should bring:
 * Test tubes and test tube holders (or any devices in which they can perform the tests)
 * Droppers
 * Funnels and/or filter paper
 * pH or litmus paper
 * Spatulas, plastic spoons, and/or stirring rods
 * 9-volt conductivity meter (not AC current)
 * Thermometer
 * Flame test equipment (nichrome wire, cobalt blue glass, etc.)
 * Slides and cover slips
 * Hand lens
 * Writing instruments
 * A pencil and ruler (for chromatograms)
 * Paper towels
 * Metal tongs
 * A 8.5".11" two sided page of any notes containing information in any form from any source
 * Non-programmable calculator

Event proctors will provide: Event proctors may provide:
 * Iodine reagent
 * 2M HCl
 * 2M NaOH
 * Benedict's solution
 * Hot water bath
 * A Bunsen burner or something similar
 * A waste container
 * Chromatography materials
 * A wash bottle with distilled water
 * Other equipment (microscope, probes, etc.)
 * Candle & matches if fibers given
 * Differential density solutions or other method of determining density if plastics are given
 * Reagents to perform other tests

Topics Covered

 * Qualitative Analysis (powders)
 * Polymers
 * Chromatography/Spectroscopy
 * Fingerprint Analysis
 * DNA
 * Glass Analysis
 * Entomology
 * Spatters
 * Seeds and Pollen
 * Tracks and Soil
 * Blood
 * Bullet Striations

Qualitative Analysis
Methods of Identification:
 * Flame test
 * Tests with liquids: Iodine, Sodium Hydroxide, Hydrochloric Acid, Benedict's solution, Water, Ammonium Chloride
 * pH
 * conductivity
 * solubility in water

Hints
 * Try to use solubility
 * How they react with the chemicals provided
 * Utilize pH
 * Burn tests can be used if necessary, but are only effective with K, B, and Li compounds (because their color is really distinct).
 * Becoming familiar with the chemicals is the key to success. Memorizing properties and reactions of powders will greatly aid in their identification.

Polymers
Methods of Identification
 * Burn test (fibers and hair only)
 * Density in liquids--oil, water, alcohol, etc. (plastics)

Other Hints

 * Burn tests for fibers, when permitted, will usually be done with a small candle (Bunsen burners are too hot).
 * Burn tests on plastics will not be permitted at the event, but burn test results may be provided. If not, it is important to know densities and other identifying properties.
 * Common liquids used to test plastic densities include water, vegetable oil, isopropyl alcohol, and NaCL solution.