Forensic Science Unit 6 - npsk12.com...Forensic Science Unit 6 Blood Spatter Packet #4 May 18th-June...
Transcript of Forensic Science Unit 6 - npsk12.com...Forensic Science Unit 6 Blood Spatter Packet #4 May 18th-June...
Forensic Science Unit 6
Blood Spatter
Packet #4 May 18th-June 5th Ms. Wines
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Assignments:
1. Forensic Files: The Wilson Murder, Analysis Worksheet
2. Blood Spatter Notes: Continued
3. Crime Case Studies
a. Case Study #1
b. Case Study #2
4. Bloodstain Practice
5. Lab #8 Distance Falling v. Surface Texture (Optional)
6. Lab #9 Direction of Travel and Angle of Impact
7. Three ‘Messy’ Blood Spatter Experiment (Optional)
8. Case Study: Unconvincing Circumstantial Evidence; Worksheet
9. Blood Detection Notes
10. It’s No Use Trying to Hide Blood … Worksheet
11. Forensic Files: Naked Justice; Questions
12. Case Study: Which Neighbor is a Killer? Worksheet
13. Case Study: The Death of Tammy’s Parrot Questions
14. Bloodstain Pattern Analysis Lab Quiz
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FORENSIC FILES: The Wilson Murder
Instructions: Watch Forensic Files The Wilson Murder, and complete the Forensic Files analysis
worksheet. https://www.youtube.com/watch?v=VXHFSHqwLmQ
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Blood Spatter Notes-Continued
Instructions: Take NOTES. Notes are available on google classroom under Unit 6-Blood Spatter 2
Spatter Pattern and type of Wound
• _______ Velocity Impact (______ ft/sec) –
_________-mist spatter pattern
• Size of Droplets – less than 1 mm
– Ex. _________________________
• ___________-Velocity Impact (_____ ft/sec)
– Size – 1-4 mm
– Ex. – ________________, _________________
• ___________-Velocity Impact (______ ft/sec)
– Size – 4 to 6 mm
– Ex – blunt object impact (_______________,
_____________, etc)
Point of origin Angle of Impact
Examination of Directionality of Blood
• Shape provides clues to ______________________ from which blood
____________________
– _________________ drop (width _____ length) – fell straight
down
• Typical of dripping ____________ (passive)
– ______________ drop (width _____ length) – possible to determine direction blood was
_____________
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• When blood comes into contact with another surface, it adheres or
__________ to it
– Point of impact may appear ___________ and _____________
than rest of drop of blood spatter
• ___________________ – keeps blood moving in direction it was traveling
– As droplet moves ________ from source, it _______________ and may produce a
thinner, ______________-like appearance
• ________ points in direction of blood’s movement
• ____________________ or _____________________ drops may appear in
_____________ of moving droplet of blood
ANGLE of IMPACT - the _____________ angle formed between the ________________ of the blood
drop and the plane of the surface it ______________.
This is the TAIL
________________________
get _________ angle of droplet from W and L
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Angle of Impact (AOI) Calculations
• accurately measuring the ________ and __________ of a bloodstain, the impact angle can be
calculated using the SIN ____________ below:
AOI = SIN-1 W / L
• W – Width of blood drop
• L – Length of blood drop
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Lines of Convergence
• ____________ of source can be determined if there
are at least ___________ drops of blood spatter.
• ______________________________ – found by
drawing straight lines down the long axis of blood
spatter and noting where they ______________
• __________ view of the location of the source
Point of Origin
• lies at a point in space _______________ the point of convergence.
o Measurement of the impact angle allows for translation of the 2-D image
(__________________) into a 3-D one (_______________).
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1. First measure the ______________ from ________ blood stain along its central axis to the
POC (distance = y)
2. Then take the TAN of the ______________ AOI.
3. Third, __________________ the TAN of the AOI by the _________________.
4. Measure that ____________ from the floor up the ________________________ axis and you
will arrive at the Point of Origin (PO)
FORMULA: PO = TAN (AOI) x y
1. Falling directly to floor @ ________________ angle will produce circular drops, with secondary
satellites being more produced in the surface hit is textured. – known as a ______________ fall.
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2. _________________ spurts or gushes typically found on walls or _____________ are caused by
the pumping actions of the __________.
3. Splashes are shaped like exclamation points. The shape and position of
the spatter pattern can help locate the position of the victim at the time
of attack.
4. Smears are left by the bleeding victim depositing blood as he or she touches or
brushes against furniture or walls.
5. Trails of blood can be left by a bleeding victim as he or she
moves from one location to another. The droplets could be
round or smeared or even appear as spurts.
6. Pools of blood form around a victim who is bleeding heavily and remains in one
place.
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Bloodstain Practice Instructions: Complete the worksheet
1. Calculate the angler of impact for the bloodstains below:
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Below is lab #8 it is not required for you to do, however you may find it enjoyable and this a hands on
activity may give you a better understanding of Blood Spatter Analysis. Encourage a family member to
help you. Additionally, be innovative on how to complete the lab and creating your own “blood like
substance.
Below are other recipes to create fake blood; especially since the instructions ask for paint and you may
not have paint. This recipe calls for materials you may have in your kitchen.
FAKE BLOOD YIELD: Makes about 1 cup
INGREDIENTS
• 3/4 cup corn syrup • 1/4 cup water • 1/2 teaspoon red food coloring • 5 drops blue food coloring • 2 drops green food coloring • 1 tablespoon corn starch
PREPARATION
In a small bowl, whisk together the corn syrup and water. Add the red, blue, and green food colorings and whisk until well combined. Whisk in the corn starch and let the liquid sit for 10 minutes to thicken.
Realistic Fake Blood
The Spruce Crafts / Rain Blanken
For a realistic look, the blood needs to have more color than pure red. A corn syrup base gives this recipe a good thickness, but it is also sticky.
Mix Together
• 2 tbsp Corn syrup • 4 drops of red food coloring • 1 tsp cocoa mix
COMPLETE LAB #9
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The lab below is not required for you to do, however you may find it enjoyable and this a hands on
activity may give you a better understanding of Blood Spatter Analysis. Encourage a family member to
help you. Additionally, be innovative on how to complete the lab and creating your own “blood like
substance. There are additional recipes to make fake blood listed on page 11 of this packet.
THIS LAB IS MESSY SO COMPLETE IN AN AREA THAT HAS EASY CLEAN UP,AND USE PAPER TO COVER FOR
PROTECTION. ADDITIONALLY, WEAR ATTIRE THAT IS DARK IN COLOR OR YOU DO NOT MIND STAINING.
The conversion for meters to feet is 1 meter = 3.28084 feet. If you do not have a protractor you can use
the link provide below to make a paper protractor (for angles do your best and estimate). https://www.google.com/search?q=making+a+protractor&rlz=1C1CHBF_enUS895US896&oq=making+a+protractor&aqs=chrome..69i57j0l7.79
78j0j7&sourceid=chrome&ie=UTF-8#kpvalbx=_K227XryMFdLL1QGrp5iQCg38
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Instructions: Read the following Case Study and complete the worksheet that follows
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Blood Detection
Instructions: Take NOTES. Notes are available on google classroom under Unit 6-
Luminol
o Used to find ___________ blood & ___________ stains.
o _____________ in the dark on contact with blood.
o The Luminol test for blood was developed by ______________________ of Germany in ______.
o Luminol is sensitive in the parts per ________________ range even for blood __________ old.
Thus, If you have ____ drop of blood in 999,999 drops of _______, Luminol will glow!!
Drawbacks
o Luminol ______ up blood during its reaction and thus ______________ ________________!
o Other popular crime scene materials like ____________ and ___________ react – Further blood
testing is a __________!
The glow of _________ fades quickly, but the glow of ___________ lasts longer.
____________ can tell if they have blood or something else.
Phenolphthalein
• Phenolphthalein is an ___________________ compound with the formula _________________
• Physical: White Powder, _______________ in water, __________________ in alcohol.
• Chemical: Acid/base indicator, laxative.
• Human blood pH 7.35 (acid or base?)
• In-
pH 8.2-12 (__________)
* it turns colorless in acidic solutions and pink in basic
solutions.
This link shows a Phenolphthalein Test:
https://www.youtube.com/watch?v=ZvhN9DDm9iI
Hydrogen peroxide
• What do you use Hydrogen peroxide on/for?
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• Why the bubbles?
______________________________________________________________________________
______________________________________________________________________________
Leucomalachite green
Malachite green is an organic compound that is used as a dyestuff and controversially as an
____________________________ in aquaculture. Malachite green is traditionally used as a ______ for
materials such as silk, leather, and paper.
Below is a link to further describe Leucomalachite green
https://www.youtube.com/watch?v=9_fsHnkn02U
This link shows a Leucomalachite green Test:
https://www.youtube.com/watch?v=HMvmEED5YTM
Benzidine
• Used in making Dyes and ____________________ blood stains
• Benzidine has been linked to _______________ and ____________________ cancer
Below is a link to further describe Benzidine:
https://www.youtube.com/watch?v=z9osQAM9rjk
This link shows a Benzidine Test:
https://www.youtube.com/watch?v=nWbPhP4OYiM
All of these are presumptive test, meaning the analysis of “a sample to establish one of the following:
1. The sample is definitely not a certain substance.
2. The sample probably is the substance.
For example, the Kastle–Meyer test ‘(Phenolphthalein Test)’ will show either that a sample is not blood or that the sample is probably blood but may be a less common substance. Further chemical tests are needed to prove that the substance is blood.
Confirmatory tests are the tests required to confirm the analysis. Confirmatory tests cost more than simpler presumptive tests so presumptive tests are often done to see if confirmatory tests are necessary.” https://en.wikipedia.org/wiki/Presumptive_and_confirmatory_tests
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Instructions: Read and complete the Worksheet-It’s No Use Trying to Hide Blood (pages 23 and 24)
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FORENSIC FILES: Naked Justice
Instructions: Watch Forensic Files Naked Justice and answer the following questions.
https://www.youtube.com/watch?v=kDUdOAzK06U
1. What did investigators use to determine how far away the gun was when it was fired?
2. Where is the gun usually found when people shoot themselves?
3. True or false: The blood in Leann’s palm is consistent with a self inflicted gunshot.
4. True or false: People who have just fired a gun should have gunshot residue on their hands.
5. True or false: Phenolphthalein is a type of chemical test to identify blood.
6. What was found on Mick’s shirt cuff?
7. True or false: High velocity blood spatter can be created when a gunshot wound hits an area with blood and the fine mist of blood blows back toward the gun
8. What did investigators use to find where Leann was when she was shot?
9. Why couldn’t the wound be self-inflicted?
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Instructions: Read the following Case Study and complete the worksheet that follows
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Instructions: Read the following Case Study and answer the related questions.
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