Determining the Cause of Different Patterns of Blood Spatter

Report
Heather Anne Yeakel
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To further understand the field of forensic
science with regard to blood spatter
To discover whether or not weapons that
cause blunt force trauma would create
different patterns of blood spatter
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Blood spatter and the reasons spatter
patterns differ was researched
Specifically, high, medium, and low velocity
spatter and the different causes of these
spatters
Blunt force trauma weapons mainly cause
medium velocity spatter, that was researched
further
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If a fist, plank of wood, and bat impact a
sponge, then their spatter patterns will be
both numerically and visually different
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1 Card Board Box
1 Sponge
1 Bat
1 Plank of Wood
1 Human Fist
1 Measurement Grid (3cm)
White Paper
Fake Blood
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44 g of Corn Starch
80 mL water
160 mL Corn Syrup
Red Food Coloring
Green Food Coloring
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Fake blood was created according to the
recipe on the materials slide
For each trial a sponge was soaked in the
blood solution and then placed in a
cardboard box lined with white paper
The weapons were used to strike the sponge
This was done three times with each weapon
and the paper was changed between each
trial
The spatters were then analyzed using a grid
system and the data was recorded
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Independent Variable
◦ Weapon used to strike sponge
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Dependant Variable
◦ Spatter pattern created by weapon
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Constant Variable
◦ Set up of the box
Average Number of Blood Spatter
Fist
Wood
Bat
Back
0.02
11.41
20.2
Front Right
1.47
4.41
22.7
Front Left
0.85
14.27
18.13
Right Side
2.37
5.92
18.44
Left Side
7.57
23.07
21.14
Average Number of Blood Spatter
Left Side
Right Side
Bat
Front Left
Wood
Front Right
Fist
Back
0
5
10
15
20
25
Standard Deviation
Fist
Wood
Bat
Back
0.17
22.94
20.05
Front Right
6.48
6.38
19.93
Front Left
12.37
24.4
17.14
Right Side
3.47
8.36
21.04
Left Side
2.35
18.86
14.89
P VALUES
Back Fist/ Back Wood
8.64E-17
Back Fist/ Back Bat
9.78E-50
Back Wood/ Back Bat
4.10E-07
Right Side Fist Right Side Wood
4.11E-06
Right side Fist/ Right Side Bat
2.55E-38
Right Side Wood/ Right Side Bat
4.80E-30
Left Side Fist/ Left Side Wood
1.55E-23
Left Side Fist/ Left Side Bat
3.78E-43
Left Side Wood/ Left Side Bat
8.11E-03
Right Front Fist/ Right Front Wood
7.28E-04
Right Front Fist/ Right Front Bat
1.53E-12
Right Front Wood/ Right Front Bat
4.04E-09
Left Front Fist/ Left Front Wood
3.56E-08
Left Front Fist/ Left Front Bat
4.52E-10
Left Front Wood/ Left Front Bat
0.50935217
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A fist, a plank of wood, and a bat created
different blood spatter patterns both visually
and numerically
If further experimentation was to be done a
device should be created to guide the weapon
to the sponge to ensure the weapons impact
the sponge at the same angle
To further expand on this topic this
experiment could be preformed with weapons
that create high velocity spatter
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Force of impact
Angle of impact
The amount of blood soaked in the sponge
The place where the sponge was struck
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Akin, L. L. (2004, May 23). Directional Analysis of Blood Spatter at Crime and Accident Scenes
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"Blood Spatter." World of Forensic Science. Ed. K. Lee Lerner and Brenda Wilmoth Lerner. Gale
Cengage, 2006. eNotes.com. 2006. 18 Oct, 2011 <http://www.enotes.com/forensicscience/
blood-spatter>
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Crime Scene Reconstruction and Blood Spatter Analysis. (n.d.). Retrieved October 8, 2011, from
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2000. Web. 30 Jan. 2012. <http://archive.suite101.com/article.cfm/crime_stories/34498>.
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http://www.crimescene-forensics.com/Blood_Stains.html
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from http://www.enotes.com/forensic-science/
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http://www.deviantcrimes.com/bloodspatter.htm
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November 3). Computer Analysis of Blood Stain Patterns on Angled Surfaces [Informative
Journal ]. Retrieved from http://www.iabpa.org/JBPA%20Sept%202011.pdf
Reynolds, M. (n.d.). Blood Spatter. Forensic Investigations. Retrieved from
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