Science Crime Busters SCB

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Science Crime Busters (SCB) Forensics (FOR)
2010 Physical Science Chemistry

• Both of these events are 5 part events
• Qualitative analysis of unknown materials
• (Water quality testing)
• Chromatography
• Crime Scene Evidence
• Analysis

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Changes
Note sheet clarified Safety clothing
requirements Change in part bwater quality
testing Removal of hairs and fibers from part
d Tie breaker rule
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Part 0 Being Prepared

• Equipment
• Bring your kit. Bring everything allowed in
  your kit.
• Safety
• Lab coat, apron or other type of front torso,
  leg and arm protection
• Eyewear Science Olympiad is very clear that
  the team must wear Chemical/Splash resistant
  eyewear. Seal around the face, do not have
  direct vents. http//soinc.org/eye_protection
• Clothing
• Closed toe shoes
• Pants long skirts acceptable but not
  recommended, no capris
• Socks
• Covered arms (see above)
• NOTE SHEET
• www.soinc.org

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Part 1 Qualitative Analysis

• In the past, this has been the worst performance
  section. For SCB this part is 50 of the score
  (only 20 for FOR).
• How to do it
• Knowing what is in your kit, how to use it and
  what it tells you is very important. Get all
  the things and have them. That includes your
  note sheet.
• SCB mixtures use a magnifying glass at first
  to try to visually test.
• Many of the substances are translucentcrystals,
  seeing dissolution on a white plate is very hard.
  Try to acquire clear plastic or glass dished for
  your teams to work with.

http//sciencekit.com/plates-and230383B-spot-pla
tes/c/3286/
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Part 1 Qualitative Analysis

• How to prepare
• Method 1 Obtain all the potential chemicals
  form the list, use every technique available on
  each chemical and record the results. This can
  be a brute force table approach or be
  incorporates into a flow chart.
• Method 2 Steal a flow chart from the
  internet.
• Neither of these substitutes for the experience
  of seeing and interpreting the results that comes
  from practice.

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Part 1 Qualitative Analysis

• Resources
• Sciencekit.com and other supply houses sell
  chemicals and equipment, WSU, your local
  university or high school science department.
• Study materials on how to do tests
• FOR--http//soinc.org/sites/default/files/upload
  ed_files/qualhints.pdf
• http//soinc.org/sites/default/files/uploaded_file
  s/forensics/For_ForensicsQualReactions.pdf
• SCB-- http//soinc.org/sites/default/files/uploa
  ded_files/crimebusters/Individual20Solid_Nonmetal
  _analysis.pdf
• http//soinc.org/sites/default/files/uploaded_file
  s/crimebusters/Liquid_analysis.pdf

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Part 2 Water Quality Testing
Water quality testing WILL happen at
Nationals. We will not be doing Water Testing at
the Utah State Competition in SCB. We will be
replacing Water Testing at the Utah State
Competition in FOR (pending approval of the event
director) with Combination and Permutation
Probabilities Team will be asked to perform
simple probability statistics using combination
and permutation formulas and interpret the
results with respect to the crime scene
information given. Information about doing these
types of calculations can be found in most
Algebra test books. http//www.mathsisfun.com/comb
inatorics/combinations-permutations.html This is
in the Algebra II section of the Utah Core
Education Standards
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Part 2 Water Quality Testing

• How to do it
• Students will be expected to use their
  calculators and know the formulas (or have them
  in their notes) and do the calculations.
• We will ask the students to present their
  answers in a 1 in X format as it is the most
  common way to express probabilities in court.
• Students may be asked to interpret the
  significance of a piece of evidence using the 1
  in X probability they calculate. That is, they
  will be asked to compare their probability versus
  a population and rate whether it is strong or
  weak. (Example)
• How to prepare
• Lots of cards, coins, dice, ice cream scoops,
  license plates and other scenarios where you have
  combinations of things with and without respect
  to the order they occur in.

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Part 3 Paper Chromatography
This is a relatively simple experiment to perform
and interpret, yet is still the second most
poorly performed section. However, it is not the
most highly weighted experiment. How to do
it Lets give it a try. This is also about
visual and quantitative comparison of the spots
that are observed. SCByou will do strict visual
comparison of the patterns/colors obtained form
the test. FORyou may be asked to include
calculations of retention factors to prove your
point (spot distance/solvent distance)
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Part 3 Paper Chromatography
How to prepare http//www.yesmag.ca/projects/pap
er_chroma.html http//soinc.org/sites/default/file
s/uploaded_files/forensics/For_Chromatography2.pdf
Get some paper towels, filter paper, coffee
filters, absorbent art paper, something that is
going to wick water via capillary action. Get
cups, beakers Get pens (not gel pens), water
color paints, MMs, Kool-aid and do it.
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Part 4 Physical Evidence

• Many possibilities
• Blood spatter evidence
• Fingerprints
• Shoe/tires
• Fingerprints
• DNA
• Glass
• Entomology
• Seeds/pollen
• Blood type
• Bullet striations

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Part 4 Physical Evidence

• Fingerprints
• 3 pattern types (arch, loop, whorl) SCB
• Each has subtypes FOR
• Plain arch, tented arch
• Ulnar loop, radial loop
• Plain whorl, central pocket loop whorl, double
  loop whorl, accidental whorl
• Identify deltas, identify ridge flow
• Types of minutiae points
• Types of development

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Part 4 Physical Evidence

• Blood stains
• Blood stains identify their direction of
  travel
• Round/circular stains landed perpendicular to
  the surface
• Oval stains have a tail that points in their
  direction of travel, opposite their point of
  origin (asin T W/L)
• Size is relative to force (velocity)

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Part 4 Physical Evidence

• DNA
• Students must be able to interpret DNA
  separations to determine possible donors
• FOR students need to be able to discuss the PCR
  process
• Shoe/Tire
• Students must be able to match shoe and tire
  tracks based on pattern comparison and individual
  characteristics

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Part 4 Physical Evidence

• FOR Event only
• Seeds/Pollen
• Just need to look at pictures, visual
  comparisons
• Soil
• Wet and dry color comparison if allowed
• Bullet striations
• Just need to look at them again
• ABO blood typing
• Conceptually is very easy to accomplish with a
  few materials, we may do this this year
• Additionally, there is a place for blood cell
  species id based on visuals

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Part 4 Physical Evidence

• Glass
• Refractive index is the amount that light
  bends, you can do numerical comparisons
• Glass fractures do not cross other glass
  fractures, tells you which crack was there first
• High impact in glass cones out the exit side
• Entomology
• Insect arrival ordering, http//www.clt.uwa.edu.
  au/__data/page/112507/fse07_forensic_entomology.pd
  f

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Part 5 Analysis of the Crime
Most important part of the whole event Need to
leave plenty of time to write it up Who and
WHY!!!! Who and WHY NOT!!!! Criminal justice is
about proof, forensics is about identification
and the strength of the association Developed a
rubric to grade on neatness, grammar, spelling,
clarity of thought, correct associations, correct
conclusions are all a part of the
score. Practice two things evidence X has this
some level of significance person Y because
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Science is Fun
but only if you know something. The students
that enjoy the event the most and the ones that
come prepared. Otherwise it is 50 minutes of
frustration. Many of the activities in these
events are qualitative and descriptive, but are
also great ways of getting students to reason
through the logical processes of scientific
discovery (read problem solving)