Forensic Science Unit 6 - Norfolk Public Schools

[Pages:34]Forensic Science Unit 6

Blood Spatter

Packet #4

May 18th-June 5th

Ms. Wines

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.



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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

This is the TAIL

ANGLE of IMPACT - the _____________ angle formed between the ________________ of the blood drop and the plane of the surface it ______________.

________________________

get _________ angle of droplet from W and L 4

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. 7

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