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REFLECTION/DO NOW:
WATCH THE FOLLOWING VIDEO ON BLOOD SPATTER AND IDENTIFY SOME OF THE DIFFERENCES THAT CAN BE SEEN IN THE TYPES OF PATTERNS THAT ARE SEEN WITH SPATTER.
ESSENTIAL QUESTION: WHAT ARE THE TYPES OF BLOOD SPATTER PATTERN?
PASSIVE BLOOD
SPATTER
THESE PATTERNS ARE FORMED SOLELY DUE TO THE EFFECT OF GRAVITY
TRANSFER
BLOOD SPATTER
PATTERNS FORMED SIMILAR
TO A STAMP TRANSFERING INK TO ANOTHER SURFACE.
THE OBJECT WILL LEAVE BEHIND THE IMPRESSION IN BLOOD
REFLECTION:ANSWER THE FOLLOWING QUESTIONS COMPLETELY. THIS WILL BE TURNED IN FOR A QUIZ GRADE.
1.TAKE THE 6 PATTERNS (IE. SMEARS, POOLS, SPURTS, ETC) AND MATCH THEM INTO THE PROPER MAIN CATEGORIES (PASSIVE, TRANSFER OR PROJECTED)
2. THEN FOR EACH CATEGORY PROVIDE A DRAWING OR AN EXPAINATION OF HOW THIS PATTERN WOULD BE CREATED/CAUSED.
ESSENTIAL QUESTION: WHAT ARE THE TYPES OF BLOOD SPATTER PATTERN?
The six patterns of blood spatter fall into 3 main categories
THESE PATTERNS ARE DUE TO FORCES THAT ARE GREATER THAN THE FORCE OF GRAVITY.
3 Categories
of Blood
Spatter
PROJECTED
BLOOD SPATTER
ESSENTIAL QUESTION: WHAT ARE THE TYPES OF BLOOD SPATTER PATTERN?
THESE FORCES CAN RESULT FROM OUTSIDE THE BODY OR FROM INSIDE THE BODY AND ALLOW THE BLOOD TO TRAVEL IN A PATH OTHER THAN DUE TO GRAVITY
POOLS FORM AROUND A VICTIM WHO IS BLEEDING HEAVILY AND REMAINS IN ONE PLACE.
POOLS
IF THE BLEEDING VICTIM MOVES TO ANOTHER LOCATION, THERE MAY APPEAR TO BE DROPLETS OR SMEARING CONNECTING THE MULTIPLE LOCATIONS
ESSENTIAL QUESTION: WHAT ARE THE TYPES OF BLOOD SPATTER PATTERN?
ESSENTIAL QUESTION: How can drops help determine direction?
CAN BE LEFT BY A BLEEDING VICTIM AS HE OR SHE MOVES FROM ONE LOCATION TO ANOTHER
The shape of an individual drop of blood provides clues to the direction from where the blood originated.
TRAILS
DIRECTIONALITY
THE DROPLETS CAN VARY AND BE ROUND OR SMEARED OR EVEN APPEAR AS SPURTS.
THE POINT OF IMPACT OF THE DROP WILL BE DARKER THAN THE REST OF THE DROP AS IT WILL HAVE THE GREATEST VOLUME OF BLOOD
ESSENTIAL QUESTION: WHY DOES BLOOD ACT LIKE IT DOES?
THE DIRECTION OF FORCE IS ALWAYS IN THE DIRECTION TOWARD THE TAIL, OR SMALLER END OF THE SMEAR OR SPATTER
ESSENTIAL QUESTION: WHAT ARE THE TYPES OF BLOOD SPATTER PATTERN?
PROPERTIES
OF BLOOD
DROPLETS
ARE LEFT BY A BLEEDING VICTIM DEPOSITING BLOOD AS HE OR SHE TOUCHES OR BRUSHES OTHER OBJECTS, LIKE A WALL OR FURNITURE
SMEARS
ESSENTIAL QUESTION: WHAT ARE THE TYPES OF BLOOD SPATTER PATTERN?
THERE ARE 6 MAIN TYPES OF SPATTER PATTERN THAT WERE IDENTIFIED IN 1902
ESSENTIAL QUESTION: WHAT ARE THE TYPES OF BLOOD SPATTER PATTERN?
SPLASHES
THESE ARE SHAPED LIKE EXCLAMATION POINTS. THE SHAPE AND POSITION OF THIS PATTERN CAN HELP LOCATE THE POSITION OF THE VICTIM DURING THE ATTACK
ESSENTIAL QUESTION: HOW ARE BLOOD TYPING TESTS PERFORMED?
TYPES OF SPATTER PATTERN
ARTERIAL SPURTS/GUSHES
ESSENTIAL QUESTION: WHY DOES BLOOD ACT LIKE IT DOES?
THESE ARE PATTERNS THAT ARE OFTEN FOUND ON WALLS OR CEILINGS THAT ARE CAUSED BY THE PUMPING ACTION OF THE HEART
DROPS OF BLOOD CAN HELP DETERMINE THE HEIGHT AND ANGLE THE BLOOD FELL FROM.
AGGLUTINATION
THE CLUMPING OF MOLECULES OR CELLS CAUSED BY AN ANTIGEN-ANITBODY REACTION
PROPERTIES
OF BLOOD
DROPLETS
OTHER PATTERNS SUCH AS SMEARS CAN TELL THE DIRECTION AND FORCE OF THE BLOW THAT CAUSED THE SPATTER
ESSENTIAL QUESTION: WHAT ARE THE TYPES OF BLOOD SPATTER PATTERN?
BLOOD FALLING DIRECTLY TP THE FLOOR AT 90 DEGREES WILL MAKE CIRCULAR DROPS, WITH SATELLITES.
ESSENTIAL QUESTION: WHAT IS BLOOD SPATTER?
PASSIVE FALL
IF A PERSON HAS THE PARTICULAR PROTEIN IN THEIR BLOOD CELLS, THE SAMPLE WILL CLUMP WHEN TESTED WITH THE ANTIGEN SERUM
In 1939 the meaning of the splatter pattern was first analyzed. It was first used in a criminal case in 1955 to exonerate a man accused of a violent crime
HISTORY OF
BLOOD SPATTER
THE FARTHER THE FALL FOR THE DROP THE LARGER THE CIRCLE AND THE MORE SATELLITES WILL OCCUR
ESSENTIAL QUESTION: WHAT ARE THE MAJOR BLOOD TYPES?
ESSENTIAL QUESTION: WHAT IS BLOOD SPATTER?
ESSENTIAL QUESTION: WHY DOES BLOOD ACT LIKE IT DOES?
ESSENTIAL QUESTION: WHAT ARE THE BASICS OF BLOOD SPATTER ANALYSIS?
It takes a grouping of blood stains to make a blood splatter pattern.
HISTORY OF
BLOOD SPATTER
WET BLOOD HAS MORE VALUE THAN DRIED BLOOD, BECAUSE MORE TEST CAN BE RUN ON IT.
When a wound is inflicted, a blood splatter pattern may be created.
ESSENTIAL QUESTION: WHY DOES BLOOD ACT LIKE IT DOES?
PROPERTIES
OF BLOOD
DROPLETS
Rh FACTOR IS ANOTHER BLOOD PROTEIN COMMONLY USED AS HUMANS EITHER HAVE THE PROTEIN OR DON'T HAVE IT
Blood Splatter Analysis
FOR EXAMPLE, ALCOHOL AND DRUG TEST CAN ONLY BE RUN ON WET BLOOD
Analysis of a splatter pattern can aid in determining the:
IF ANY BLOOD DOES ESCAPE COHESION IT WILL CREAT SECONDARY DROPLETS CALLED SATELLITES
ESSENTIAL QUESTION: WHAT ARE THE MAJOR BLOOD TYPES?
OTHER BLOOD PROTEINS USED IN BLOOD TYPING
PROPERTIES
OF BLOOD
DROPLETS
The pattern can help to reconstruct the events surrounding a shooting, stabbing, or beating.
ESSENTIAL QUESTION: HOW IS HUMAN BLOOD DIFFERENT THAN ANIMAL BLOOD?
ESSENTIAL QUESTION: WHY DOES BLOOD ACT LIKE IT DOES?
IF YOU DONT HAVE IT YOU ARE Rh - AND IF YOU HAVE IT YOU ARE Rh +. ABOUT 85% OF HUMANS ARE Rh +
ESSENTIAL QUESTION: HOW DO SCIENTISTS USE BLOOD EVIDENCE?
ESSENTIAL QUESTION: WHAT ARE THE BASICS OF BLOOD SPATTER ANALYSIS?
ESSENTIAL QUESTION: WHAY DOES BLOOD ACT LIKE IT DOES?
MOST VERTEBRATES HAVE ESSENTIALLY THE SAME BLOOD CELLS, WITH RED AND WHITE BLOOD CELLS AND PLATELETS.
WHY IS BLOOD TYPING COMMONLY USED IN CSI?
SINCE BLOOD IS COHESIVE AND FORCES ACT TO KEEP IT TOGETHER, DROPLETS RESITST FLATTENING EVEN AFTER HITTING A SURFACE (FIGURE 3)
BLOOD FORMS DROPLETS AS IT FALLS, DUE TO COHESION AND MOLECULES STICKING TOGETHER (FIGURE 1)
CAN BE ANALYZED TO DETERMINE BLOOD TYPE AND DNA, WHICH CAN BE MATCHED TO A GROUP OR INDIVIDUAL SUSPECTS
THE PATTERNS LEFT BY FALLING BLOOD, OR SMEARED BLOOD HELP THE CSI INETRPRET AND RECONSTRUCT WHAT HAPPENNED AT A CRIME SCENE
RELEVANCE OF BLOOD SPATTER
EVIDENCE
Given the frequency of different genes within a population, it is possible to determine the probability that a particular blood type will appear in a particular population or ethnicity/culture.
BLOOD SAMPLES
PROPERTIES
OF BLOOD
DROPLETS
ESSENTIAL QUESTION: WHAT IS BLOOD MADE OF?
PROPERTIES
OF BLOOD
DROPLETS
THIS ALSO WILL RESULT IN THE ROUND SHAPE OF THE DROPLET ITSELF
MOST INVERTEBRATES HAVE AN OPEN CIRCULATORY SYSTEM THAT HAS ONLY ONE TYPE F CELL IN THE "BLOOD".
AS A RESULT GRAVITY ACTS ON DROPLETS AS THEY FALL AND MAKES THE DROPLET LONGER THAN IT IS WIDE. (FIGURE 2)
ESSENTIAL QUESTION: WHAT ARE THE MAJOR BLOOD TYPES?
VERTEBRATES
VS. INVERTEBRATES
CAN BE ANALYZED TO GIVE CLUES TO THE LOCATION OF A CRIME, MOVEMENT OF A VICTIM, AND TYPE OF WEAPON USED
BLOOD DROPLETS
Blood typing is quicker and less expensive than DNA profiling.
DIFFERENCES BETWEEN VERTEBRATES RANGE FROM THE TYPE OF ANTIGENS TO WHAT THE MATURE RED BLOOD CELLS LOOK LIKE.
BLOOD SPATTER
CAN BE ANALYZED TO DETERMINE PATTERNS THAT GIVE INVESTIGATORSCLUES TO HOW A CRIME MIGHT HAVE HAPPENNED
WHY IS BLOOD TYPING COMMONLY USED IN CSI?
THE CLOSER THE ANIMALS ARE IN TERMS OF ANCESTORS, THE LESS DIFFERENCES THERE ARE
ESSENTIAL QUESTION: WHAT IS BLOOD MADE OF?
It produces class evidence but can still link a suspect to a crime scene or exclude a suspect.
Whole blood carries cells and plasma—the fluid with hormones, clotting factors, and nutrients.
EACH BLOOD CELL PERFORMS A DIFFERENT IMPORTANT FUNCTION
Composition of Blood
ESSENTIAL QUESTION: WHAT ARE THE MAJOR BLOOD TYPES?
THERE ARE 4 MAJOR TYPES:
WHAT ARE THE FREQUENCIES OF BLOOD TYPE IN THE HUMAN POPULATION?
Red blood cells carry oxygen to the body’s cells and carbon dioxide away.
REFLECTION/DO NOW:
ANSWER THE FOLLOWING QUESTIONS USING YOUR NOTES AND IN COMPLETE SENTENCES.
1. WHY IS BLOOD TYPE CONSIDERED "CLASS EVIDENCE"?
2. HOW IS THIS DIFFERENT THAN
DNA PROFILING?
White blood cells fight disease and foreign invaders and, alone, contain cell nuclei.
Composition of Blood
IN YOUR NOTES ANSWER THE FOLLOWING QUESTION:
WHICH BLOOD CELLS CONTAIN DNA AND WHY?
PLASMA IS SIMILAR TO SALT WATER IN COMPOSITION AND CONTAINS:
Platelets aid in blood clotting and the repair of damaged blood vessels.
ESSENTIAL QUESTION: HOW CAN BLOOD BE USED AT A CRIME SCENE?
ESSENTIAL QUESTION: WHAT ARE THE MAJOR BLOOD TYPES?
YOUR BLOOD TYPE IS BASED ON THE PROTEINS THAT ARE FOUND IN YOUR BLOOD
How do you get your blood type?
THESE PROTEINS ARE FOUND IN THE MEMBRANE OF YOUR RED BLOOD CELLS
Blood typing can provide class evidence; whereas DNA profiling can provide individual evidence.
The antigens in the ABO system are the most common antigens found on red blood cells.
• A persons red blood cell may possess either only A antigens and B antigens both classes A and B (type AB) or neither class A or B antigens (O).
• People who are type A tolerate their own class A antigens but produce antibodies against B antigens. This causes red blood cells to clump together.
• Type B people produce antibodies against class A antigens,
• Type AB produce neither class A or B antigens, and type O produce antibodies against both class A and class B antigens.
Methods for detecting blood
HISTORY
AND INTRO TO
BLOOD
A blood spatter pattern can give information about the truthfulness of an account by a witness or a suspect.
Characteristics of Saliva and Semen
It also can provide information about the origin of the blood, the angle and velocity of impact, and type of weapon used.
ESSENTIAL QUESTION: HOW CAN BLOOD BE USED AT A CRIME SCENE?
Titanium dioxide
BLOOD HAS BEEN STUDIED FOR 1000S OF YEARS AND ADVANCEMENTS HAVE LED TO IT BEING ONE OF THE BEST FORENSIC TOOLS
Types of bloodstains
Luminol
Problems with presumptive test
Altered stains
Types of bloodstains
Flows