Forensics

Description
Forensics is a 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.

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

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

Polymers:
 * Flame tests
 * Density

Fibers:
 * Flame tests
 * Check results with senses ( ie: smell)

Usually at competition, it's hard to do flame tests because you are given a candle or something similar, but Bunsen burner are rarely given. Though burn tests will give you the correct results for powders and fibers, they may not be allowed at some competitions, so you have to know other ways to identify them, such as density, color, or texture. The latter 2 work only for fibers because the polymers are all clear and feel like plastic.

Hints for identifying powders

 * 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.