Difference between revisions of "Forensics"

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(Polymers)
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|2011tests=[http://scioly.org/wiki/2011_Test_Exchange#Forensics 2011]
 
|2011tests=[http://scioly.org/wiki/2011_Test_Exchange#Forensics 2011]
 
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==Description==
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Forensics is a chemistry event that involves identification of powders, polymers, fibers, and hair samples, blood serum and fingerprint analysis, and  interpretation of chromatography.
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'''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.
 
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.
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This event is closely associated with the [[Division B]] event, [[Crime Busters]].
  
 
==Equipment==
 
==Equipment==
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*Density in liquids--oil, water, alcohol, etc. (plastics)
 
*Density in liquids--oil, water, alcohol, etc. (plastics)
  
Hints
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==Other Hints==
 
*Burn tests for fibers, when permitted, will usually be done with a small candle (Bunsen burners are too hot).   
 
*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.
 
*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.

Revision as of 20:26, 20 June 2011


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. 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:

  • 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

Event proctors may provide:

  • 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.