# Shared Flashcard Set

## Details

FRSC 511 Midterm
BPA/SIR Rancourt
55
Criminology
02/13/2020

Term
 How much blood do you need to lose to die from blood loss?
Definition
 40%
Term
 How much blood does the average male have in his body?
Definition
 5-6L of blood
Term
 How much blood does the average female have in her body?
Definition
 4-5L of blood
Term
 Define Bloodstain Pattern Analysis
Definition
 It is the examination of the shapes, locations, and distribution patterns of bloodstains, in order to provide an interpretation of the physical events that occurred at the crime scene
Term
 In BPA, what is the target surface?
Definition
 Any surface that blood comes into contact with
Term
 What can blood stain analysis tell us?
Definition
 Direction of travel of the blood; distance of blood source to target surface; angle of impact of blood droplet; Determination of blood trail, their direction, and relative speed of motion; nature of the object used to cause the bloodshed, the number of blows involved, and relative location of persons and objects; sequencing of multiple blows; position of a victim during the fatal impact; corroborate or refute statements; establish order of certain events; determine blood collection sites for DNA
Term
 Define Cohesive Forces in BPA
Definition
 The attraction of like molecules to remain together as a unit
Term
 Define surface tension for BPA
Definition
 The cohesive forces that cause a fluid to remain in the form of a sphere.
Term
 Define viscosity for BPA
Definition
 The resistance of a fluid to flow freely.
Term
 What is the difference in viscosity between water and blood?
Definition
 Blood is 3-6 times greater than water
Term
 The [blank] the force, the [blank] the droplets
Definition
 greater, smaller
Term
 larger drops travel [blank]
Definition
 Farther
Term
 What causes blood to break apart?
Definition
 Force
Term
 With increased distance, what will happen to the diameter of the drop stain?
Definition
 It will increase
Term
 Diameter of drop will [blank] with [blank] distance
Definition
 increase, increased
Term
 What shape does blood travel through air in?
Definition
 Sphere
Term
 As the angle of impact decreases, what happens to the stain?
Definition
 It elongates
Term
 Define angle of impact
Definition
 angle at which the blood drop hits the target surface
Term
 What dimensions are used to determine the angle of impact?
Definition
 Length and width of stain
Term
 textured target surfaces will affect [blank] and [blank] of drop
Definition
 size, shape
Term
 Which end of the stain tells the directionality?
Definition
 The tail of the drop points to the direction of travel
Term
 If there is no tail, how does one determine the directionality of the stain?
Definition
 Look for the greatest edge of disruption
Term
 Define cast-off
Definition
 where a smaller droplet is cast from a parent drop at impact
Term
 Name the types of bloodstain patterns
Definition
 Drip stain, impact, projected stain, expirated, cast-off, arterial spurting / gushing, transfer, swipe, wipe
Term
 Describe the drip stain
Definition
 A bloodstain resulting from a falling drop that formed due to gravity, forms a generally circular stain
Term
 Describe impact bloodstain patterns
Definition
 A bloodstain pattern resulting from an object striking liquid blood. Forms a pattern where the stains radiate outward
Term
 What causes a projected bloodstain pattern?
Definition
 The ejection of a volume of blood under pressure
Term
 What creates a cast-off pattern?
Definition
 blood drops are released from an object due to its motion
Term
 True or False: Cast-off patterns are only of the 2nd and subsequent blows.
Definition
 True
Term
 What is an expirated pattern?
Definition
 a pattern resulting from blood forced by airflow out the nose, mouth, or a wound
Term
 True or False: With a cast-off pattern you may have two directions.
Definition
 True, toward and away from the victim
Term
 What causes an arterial spurt pattern and what is it characterized by?
Definition
 it is blood exiting the body due to pressure from a breach artery and characterized by large volume stains; may see rise and fall like the heart beat
Term
 What causes a transfer pattern?
Definition
 caused by contact between a blood-bearing surface and another surface
Term
 What is a swipe pattern?
Definition
 A stained object moves over an unstained surface. Blood transferred from a bloody object to a non bloody object with motion.
Term
 How do you tell directionality with a swipe pattern?
Definition
 Look for feathered edges for directionality
Term
 What is a wipe pattern?
Definition
 An altered bloodstain pattern resulting from an object moving through a pre-existing wet bloodstain
Term
 What is a perimeter stain?
Definition
 An altered stain that consists of the peripheral characteristics of the original stain. Previously known as a skeleton stain
Term
 What is a void in BPA?
Definition
 The absence of blood in an otherwise continuous bloodstain. basically something was there during the blood letting event, but since moved since the analysis
Term
 How do you document bloodstain patterns?
Definition
 Notes, photos, sketch
Term
 What is the orientation photograph?
Definition
 It is the equivalent of the midrange photograph and establishes the pattern to a fixed feature
Term
 What is the distribution photo / pattern photo?
Definition
 with a scale and the lens plane parallel to the surface with blood it shows the overall pattern
Term
 What is the difference between a distribution photo and the close up photo?
Definition
 The distribution photo is of the entire pattern. The close up is of individual stains within the pattern
Term
 What should sketches of bloodstain patterns include?
Definition
 placement of the patterns, descriptions of the patterns, any measurements: dimension of the overall pattern, W and L of individual stains, Horizontal and vertical measurement of individual stains
Term
 What are some things that should be documented in the notes for bloodstains?
Definition
 environmental conditions, handedness of suspect and victim, physical description of individuals, blood on suspects and victims, color of stains, degree of dampness of stains, location of patterns, description of patterns, items collected or moved
Term
 What are some safety precautions when working with bloodstains?
Definition
 treat all blood as a possible infectious material, wear latex gloves, wear face mask, shoe protection if possible, report exposures to supervisor, no pens or pencils in mouth
Term
 How is area of convergence determined.
Definition
 By taking a ruler down the center of the stains and drawing a line till the many of the test stains converge to an area on the wall.
Term
 How is the angle of impact calculated?
Definition
 Measuring the length and the width, dividing the width by the length, and then taking the inverse sine. plus or minus 5 degree error okay.
Term
 What is the area of origin
Definition
 it is the point of impact in the 3rd Dimension calculated with the angle of impact, stringing, and the area of convergence
Term
 What is the area of convergence?
Definition
 It is the point in 2 dimensions where the stains converge, measured through the long axis of the stain.
Term
 In shooting trajectory what shapes of holes may you see?
Definition
 Circular, oval, non-descript, rectangular
Term
 What does a circular hole indicate?
Definition
 90 degree impact angle
Term
 What does an oval bullet hole indicate?
Definition
 impact angle less than 90 degrees
Term
 What does a non-descript bullet hole indicate?
Definition
 impact angle made by a damaged projectile
Term
 What does a rectangular bullet hole indicate?
Definition
 Impact angle made by a tumbling projectile
Term
 True or False: You must have at least two defects to determine the angles.
Definition
 True, otherwise the dowel could be at any angle
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