FORENSIC SEROLOGY: BLOOD SPATTER ANALYSIS (BSA)



FORENSIC SEROLOGY: BLOOD SPATTER ANALYSIS (BSA)Goals: by the end of these lessons, the students will have an overview understanding of how the blood pattern found at a crime scene may be used to reconstruct the crime. They will be able to conduct blood-spatter analysis in order to recreate events at a crime scene and describe the nature of the weapon mon Core Learning Standards:CCSS.ELA-Literacy.RST.11-12.9 Synthesize information from a range of sources (e.g., texts, experiments, simulations) into a coherent understanding of a process, phenomenon, or concept, resolving conflicting information when SS.ELA-Literacy.RST.11-12.7 Integrate and evaluate multiple sources of information presented in diverse formats and media (e.g., quantitative data, video, multimedia) in order to address a question or solve a LS-Writing 11-12.2: Write informative/explanatory texts to examine and convey complex ideas, concepts, and information clearly and accurately through the effective selection, organization, and analysis of content. CCLS-Speaking and Listening 11-12.3: Evaluate a speaker’s point of view, reasoning, and use of evidence and rhetoric, assessing the stance, premises, links among ideas, word choice, points of emphasis, and tone used. DAY 1AIM: What are some of the important crime scene facts which may be determined using blood spatter analysis? Do Now: In the SHOWTIME show DEXTER, Dexter is a blood-spatter expert. What does he do with the blood, and how is his work important in crime-scene reconstruction? Distribute vocabulary handout allow students 5 minutes to read the terms and go over any questions they might have.Go over PowerPoint presentation slides 1-7, with special emphasis on crime scene reconstruction. HOMEWORKRead about the Sam Sheppard case at truTV’s Crime Library.Write a one page summary on the Sam Sheppard case, following rubric directions.BLOOD-SPATTER VOCABULARYLines of Convergence- A two-dimensional view of the intersection of lines formed by drawing a line through the main axis of at least two drops of blood that indicates the general area of the source of the blood spatter.Point of Origin-A three-dimensional view formed using lines of convergence and angles of impact of at least two different drops of blood to identify the source and location of blood spatter.Satellite Drop of Blood- Secondary drop formed when some blood breaks free from the main contact drop of blood.Contact stain—bloodstains caused by contact between a wet blood-bearing surface and a second surface that may or may not have blood on itTransfer—an image is recognizable and may be identifiable with a particular objectSwipe—wet blood is transferred to a surface that did not have blood on itWipe—a non-blood-bearing object moves through a wet bloodstain, altering the appearance of the original stainAngle of impact—angle at which blood strikes a target surfaceBloodstain transfer—when a bloody object comes into contact with a surface and leaves a patterned blood image on the surfaceBackspatter—blood that is directed back toward the source of energyCast-off—blood that is thrown from an object in motionDAY 2AIM: What are some of the factors which affect the size and shape of a blood drop?DO NOW: Draw a blood-drop falling through the air towards the ground. Describe its shape.Go over PowerPoint presentation slides 8-23, with special emphasis on calculating angle of impact.VocabularyDirectionality—relates to the direction a drop of blood travels in space from its point of origin Terminal velocity—the greatest speed to which a free-falling drop of blood can accelerate in air. It is dependent upon the acceleration of gravity and the friction of the air against the blood—approximately 25.1 feet/second. High velocity—greater than 25 feet per second, usually 100 feet per second; gives a fine mist appearance Medium velocity—5 to 25 feet per second Low velocity—5 feet per second or lessDAY 3AIM: How do blood-spatter experts determine the source of the blood (directionality) based on impact angle?Do Now (10): 1. Watch the YouTube video “science of Murder: Blood Spatter”. Answer the following from what you learned in the last few days and from watching the video:Why are safety precautions important when handing real human blood?What is stringing and how is it important in reconstructing a crime?Compare your answer with your partnerVocabularyDirectionality—relates to the direction a drop of blood travels in space from its point of origin. Macabre- disturbing and horrifying because of involvement with or depiction of death and injury.ACTIVITY (20)Go over PowerPoint presentation slides 23-39, with special emphasis on blood spatter types. Exit Slip (10)Use the formula and your calculator to determine the angle of impact for the following drop. Compare your answer with that od your partner.DAY 4Area of Convergence-OR-Point of OriginAIM: How do Blood spatter analysts determine the location of the source of the blood?Do Now: Use the formula you learned in the previous lesson to calculate impact angle of a blood drop whenLength = 25 mmWidth = 15 mmNote: If you are not sure about the formula, or how to do it, check with your partnerACTIVITY:Slides 29-32Vocabulary: Area of convergence, point of originYou tube videowatch?v=3jFKZaSeNjgAfter watching the short video answer the following:1. Why do you think do they select certain blood drops?Do you see any advantages and disadvantages through the selection process? Exit Slip: Forensic investigations/area of convergence handoutWork in pairs: Predetermined groups based on cycle 2 gradesDAY 5AIM: How do blood spatter analysts categorize blood stains?Do Now: Use the formula you learned to find the angle of impact for the following drops:The width is 9mm and the length is 18mm2. The width is 1.5 cm and the length of the blood stain is 3.0cm3. The width is 1.73cm and the length is 2cmACTIVITY:Slides 33-41Vocabulary: passive, projectedExit Slip: Slide #41: Describe how the following bloodstains were producedDAY 6AIM: How do we use the right triangle and the law of tangents to determine the height of blood spatter?DO NOW: Describe how the following bloodstains were produced (i.e., low, medium, or high velocity spatter) . Please provide an explanation for your choices. SLIDE #41ACTIVITY:Slides 41-54Vocabulary: passive, projected3 problems in determining the point of originGOALS: The goal of this lesson is to:Review some important information discussed in class on BSAFeature the work of one prominent scientist in the field of BSAEncourage literacy in the classroomAIM: How do Brian Kennedy and other BP Analysts solve cases using blood spatter?DO NOW: Distribute article and group studentsDIFFERENTIATION: Students will be paired according performance in prior literacy activities and classroom observation.CLASS ACTIVITY: Students will read article on BPA and answer the questions on separate paper. Question 3 must also be answered in the student’s notebook, as it may be included in the unit exam.ASSESMENT: Pair work will be collected and graded. Misunderstandings will be dealt with during the following do now activity.List three important facts about BSA you learned this past week. ORWrite one sentence to describe the relationship between angle of impact and shape of the blood drop. ................
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