Determining the Cause of Different Patterns of Blood Spatter

1. Determining the Cause of Different Patterns of Blood Spatter Heather Anne Yeakel

2. Rationale • 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

3. Research • 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

4. Hypothesis • If a fist, plank of wood, and bat impact a sponge, then their spatter patterns will be both numerically and visually different

5. Materials • 1 Card Board Box • 1 Sponge • 1 Bat • 1 Plank of Wood • 1 Human Fist • 1 Measurement Grid (3cm) • White Paper • Fake Blood • 44 g of Corn Starch • 80 mL water • 160 mL Corn Syrup • Red Food Coloring • Green Food Coloring

6. Procedure • 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

7. Variables • Independent Variable • Weapon used to strike sponge • Dependant Variable • Spatter pattern created by weapon • Constant Variable • Set up of the box

8. Photos

9. Average Number of Spatters

10. Data

11. Standard Deviation

12. T-TEST Results

13. Conclusion • 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

14. Sources of Error • Force of impact • Angle of impact • The amount of blood soaked in the sponge • The place where the sponge was struck

15. Refrences • Akin, L. L. (2004, May 23). Directional Analysis of Blood Spatter at Crime and Accident Scenes for the Private Investigator. Retrieved from http://www.akininc.com/‌PDFs/‌Directional%20Analysis%20for%20PI’s%20condensed.pdf • "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/forensic-science/
blood-spatter> • Choosing A Baseball Bat. (n.d.). Retrieved 2008, from http://www.baseball-bats.net • Crime Scene Reconstruction and Blood Spatter Analysis. (n.d.). Retrieved October 8, 2011, from http://www.angelfire.com/‌sc3/‌cjrp/‌csr.html • Ely, Catten. “The Forensic Practice of Blood Spatter Interpretation.” suite 101. N.p., 14 June 2000. Web. 30 Jan. 2012. <http://archive.suite101.com/‌article.cfm/‌crime_stories/‌34498>. • Interpreting Blood Stain Patterns. (n.d.). Retrieved from Crime Scene Forensics LLC website: http://www.crimescene-forensics.com/‌Blood_Stains.html • Lerner, E. K. L., Lerner, B. W., & Cengage, G. (2006). Blood Spatter. Retrieved October, 2011, from http://www.enotes.com/‌forensic-science/ • Nelson, B. (2011, January 3). Blood Spatter. Retrieved from Deviant Crimes website: http://www.deviantcrimes.com/‌bloodspatter.htm • Nowack, L., Collins, R., Li, G., Carter, A., Illes, M., Gorman, V., . . . Stotesbury, T. (2011, 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 http://www.clt.uwa.edu.au/‌__data/‌page/‌112508/‌fsb05.pdf