Forensic Science: Blood Spatter Across The Curriculum
Forensic Science: Blood SpatterAcross the CurriculumNSTA 2012Kathy Mirakovits (member IABPA)IB Physics, IB Biology & Forensic Science TeacherPortage Northern High School Portage, Michigankmirakovits@gmail.com
Physical Properties of Blood Blood has a fairly high surfacetension Blood is very viscous Blood tends to adhere toexternal surface Blood that falls from bodymoves as an oscillating spherehttp://www.ameslab.gov/mfrc/bpa videos Kathy Mirakovits, Forensic Science Educational Consulting. LLC
Physical Properties of Blood Size of spherical blood dropletdepends upon size of surfacefrom which it falls (largersurface more volume largerdroplet) Height of fall changes diameterof blood drop (closer toground smaller diameter) Blood reaches terminal velocityat approximately 7 feet anddiameter will not increase10 cm drop10 0cm drop Kathy Mirakovits, Forensic Science Educational Consulting. LLC
Physical Properties of Blood Spines—protrusions from the parent blood drop Satellite spatter—smaller droplets that leave parent drop and land near it Disruption of surface tension and cohesive properties of blood due totype of target surfaceSpinesAESatellite SpatterBFCG Kathy Mirakovits, Forensic Science Educational Consulting. LLCDH4
Your Turn Use the ‘Drip and Projected Blood’ Drip blood onto 2 surfaces notecards & cloth drip from 15 cm , 30 cm and 45 cm Discussion! Kathy Mirakovits, Forensic Science Educational Consulting. LLC
Bloodstain Pattern Categories Passive stains : move only underinfluence of gravity Spatter stains: arise from a force inaddition to gravity Altered stains: are physically orphysiologically changed Kathy Mirakovits, Forensic Science Educational Consulting. LLC
Passive BloodstainsVertical drips & Multiple DripsLarge volumeLarge amount of blood hitstarget at one timeFlowPrints (shoe, hand, hair, etc)etc)Natural movement of largeblood depositSwipeBloodied object leaves transferof blood showing motion Kathy Mirakovits, Forensic Science Educational Consulting. LLC7
Your Turn Vertical Drips Drip blood onto notecards from 60 cm, 75 cm and100 cm. Compare to the 15, 30 & 45 cm What can you do with this? Discussion! Try other stains: multiple drips, swipe, prints Discussion! Kathy Mirakovits, Forensic Science Educational Consulting. LLC
Spatter BloodstainsImpact Spatter Due to Blunt Force Result of bloodied object receiving a blowMust have blood on surface to create this type of patternFirst blow does not generally produce impact stainBloodstains are typically 11-4 mm in sizeImpact due to blunt force Kathy Mirakovits, Forensic Science Educational Consulting. LLC
Spatter Bloodstains Impact Spatter Due to Gunshot Bloodstains 1mmin length Misty appearanceImpact Dueto Gunshot Cast Off Linear pattern of blood leavingweapon such as knife, bat, or hand Kathy Mirakovits, Forensic Science Educational Consulting. LLCSimulating a CastOff Pattern
Spatter Bloodstains Arterial Large amount of blood underpressure Arc pattern Due to breach of major artery(carotid, femoral) Expirated Blood ejected with force fromrespiratory system Similar pattern to impact spatter,but may contain air bubbles Kathy Mirakovits, Forensic Science Educational Consulting. LLC
Altered Bloodstains Physiologically Altered Stains Insect activity—trails Addition of foreign (non(non-blood) material Physically Altered Stains Void—absence of blood where it should be Wipe—existing bloodstainaltered by secondary motion through itWipe Kathy Mirakovits, Forensic Science Educational Consulting. LLCVoids
“Stringing” a Bloodstain Pattern Kathy Mirakovits, Forensic Science Educational Consulting. LLC
Projectile Motion ActivityFind the Position of the Blood Source Blood in flight obeyslaws of gravity—gravity—aprojectile Use impact spatterdue to blunt forcetrauma Use trigonometry tolocate position ofsourceBlood cast onto a surface at an angle has anelliptical shape Kathy Mirakovits, Forensic Science Educational Consulting. LLC
Analyzing the Motion of a Blood DropletθAB(width) sinBC (length) 1ABCBABDroplet’sMotion VectorθAΘΘB Kathy Mirakovits, Forensic Science Educational Consulting. LLCC
Typical Blood ShapesAt Various Impact Angles100200300400500600700800900 Kathy Mirakovits, Forensic Science Educational Consulting. LLC
Simulating Angled Blood Drops Impact Angle ApparatusNotecardProtractorFront ViewClipboardTable Kathy Mirakovits, Forensic Science Educational Consulting. LLC
Your Turn Use the impact angle clipboard to make sampleangled bloodstains Remember the impact angle is 900 minus theangle of the clipboard! Example for a 30 degree impact angle set yourboard at 90-30 or 60 degrees. Drip blood at 30 cm from the board surface Count to 10 and let the board return to horizontal Try dripping at 300, 600 and 800 Discussion! Kathy Mirakovits, Forensic Science Educational Consulting. LLC
LengthMeasure onlythe ellipse ofthe stain—stain—not the tail.widthMeasure only theround part of thestain—stain—not thespines.spinesMathematics ofBloodstains Measure width &length of bloodstain todetermine impact angle. Kathy Mirakovits, Forensic Science Educational Consulting. LLC19
Calculating Impact Angles Impact Angle (θ(θ) (sin-1) width/length Practice Sheet. Blood Drop A: W/L 0.9cm/2cm270Blood Drop B: W/L 1.2cm/1.9cm 390Blood Drop C: W/L 0.7cm/2cm200 Kathy Mirakovits, Forensic Science Educational Consulting. LLC
Area of ConvergenceArea or Region of Convergence21Area or Region ofConvergence53Steps to Determine Area or Region of Convergence1. Contruct Ray Through Long Axis of Each StainLeading Away From Satellite or Spines2. Locate Area or Region of Convergence43. The Center of that Area is Working Point for Origin Kathy Mirakovits, Forensic Science Educational Consulting. LLCFSW 1998
Finding the Third DimensionTan(θ ) P / DP Tan(θ ) * DPBlood dropletθFrom Area of ConvergenceD Kathy Mirakovits, Forensic Science Educational Consulting. LLC
Impact Angles1. 2/5Finding the Third Dimension24072. 1.5/4 2203. 1/3P D (Tan θ)1. 4.9 cm2002. 6.1 cm4. 2/4.5 2605. 3/63006. 2/43007. 1/41403. 5.3 cm325. 4.2 cmTan θ P/D4D (point to stain)1. 11 cm2. 15 cm4. 4.5 cm6. 5.6 cm67. 5.1 cm5Conclusion:1The source was 4.2to 6.1 cm above thePoint of Convergence3. 14.5 cm4.9.3 cm5. 7.3 cm6. 9.7 cm7. 20.6 cmPoint ofConvergence
Supplies for ActivitiesBlood Spatter Kits from Wards Natural Science Introduction to Blood Spatter Analysis: 36 V 0047 Advanced Techniques in Blood Spatter Analysis. 36 V 0048 Simulated Drip & Projected Blood. 37 V 5310 Simulated Transfer Blood. 37V5311 Kathy Mirakovits, Forensic Science Educational Consulting. LLC
Thank You—You—Questions? Contact Information: Kathy d.com Forensic Science Workshops Summer 2012Atlanta, GAJune 1212-15Portland, ORJune 2626-29LTU (Southfield, MI) July 99-13IUPUI (Indianapolis) July 1717-20Portage, MIJuly 3030-Aug 3 Textbook? www.crcpress/com Kathy Mirakovits, Forensic Science Educational Consulting. LLC
Forensic Science Workshops Summer 2012Forensic Science Workshops Summer 2012 Atlanta, GA Atlanta, GA June 12 June 12June 12- ---15115515 Portland, ORPortland, OR June 26 June 26June 26- ---29229929 LTU (Southfield, MI) LTU (Southfield, MI) July 9 July 9July 9- ---13113313
1 Forensic Science: Fundamentals & Investigations, Chapter 8 Blood Spatter o 1894 – Pitoroski wrote earliest reference to blood spatter analysis. o 1939—spatter patterns first analyzed by Balthazard (speed of blood influences shape of the stain) o Blood may spatter when a wound is inflicted o Blood spatter pattern—a grouping of blood stains o Patterns help to reconstruct the events
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blood‐spatter evidence tells a different story than the witness’s account of the incident. Lesson Activities In this activity, students analyze blood spatter in three dimensions. By noting the shape of the droplet of blood, the direction in which the blood was moving can be determined.
May 09, 2014 · May 09, 2014 · Blood Spatter Labs You will be creating sample drop patterns using single drops and multiple drops. We will also investigate the effect of motion and the angle of impact on blood spatter. This can be messy! Be very careful to keep the blood on the paper and not on yourself, the table, or floor.
Forensic science is the application of science to law. Any science can be applied into a legal situation, but some of the commonest forensic sciences include forensic biology, forensic chemistry, and forensic toxicology. The word forensic in today’s world simply
The Center for the Future of Forensic Science at BGSU offers unparalleled experiential learning to forensic science students and a gateway to advanced training and cutting edge forensic science research for practicing forensic scientists, forensic science technicians, crime scene investigators, and other law enforcement professionals.
The Center for the Future of Forensic Science at BGSU offers unparalleled experiential learning to forensic science students and a gateway to advanced training and cutting edge forensic science research for practicing forensic scientists, forensic science technicians, crime scene investigators, and other law enforcement professionals.
educators, forensic science practitioners, and members of professions associated with forensic science about their conceptions of forensic science knowledge, practice, and identity. This outcome of the methodology has been the proposition of critical features relating to the nature of forensic science. These critical features have become the basis
