What Cannot be determined by blood spatter?
Which of the following CANNOT be determined by observing blood spatter? The DNA of the victim. The position of the assailant at the time of the spatter.
Which is more likely to be deposited on the object or person creating the impact?
Forward spatter is projected outward and away from the source. Back spatter is more likely to be deposited on the object or person creating the impact. It is created when an object blocks the deposition of blood spatter onto a target surface or area.
What are the 4 types of passive bloodstains?
Passive bloodstains can be further subdivided to include drops, drip patterns, pools, and clots.
- Passive Bloodstain. Passive Bloodstain on a rough surface (such as wood or concrete)
- Projected Bloodstain. Projected Bloodstain, possibly a Cast-Off Pattern or a HVIS.
- Transfer Bloodstain.
How does the velocity of impact change the blood stain pattern?
When blood is impacted, droplets are dispersed through the air. When these droplets strike a surface, the shape of the stain changes depending on the angle of impact, velocity, distance travelled and type of surface impacted.
What are the two most common methods for documenting blood patterns?
The most frequently use tools for collecting bloodstain evidence is high-resolution photography because it provides quality presentations for subsequent courtroom testimony and allows for outside analysis by other experts. Other methods used for evidence documentation is by note taking, sketching, and video recording.
What factors affect blood spatter patterns?
The appearance of these blood patterns is affected by the forcefulness of the impact, the volume of blood impacted, the surface characteristics of the blood source, the characteristics of the surface the blood is deposited on, and what is impacting into the blood to put it in flight (Fig.
What are the six types of blood spatter patterns?
Terms in this set (35)
- Angle of impact. The acute angle formed between the direction of a blood drop and the plane of the surface it strikes.
- Arterial Spurting (or gushing) pattern.
- Back Spatter.
- Blood Spatter Analysis.
- Bloodstain.
- Cast-off pattern.
- Contact stain.
- Direction of flight.
What shape does a passive drop of blood at a 90 degree angle have?
When a droplet of blood strikes a surface perpendicular (90 degrees) the resulting bloodstain will be circular.
What is a satellite drop of blood?
satellite spatter. small drops of blood that break off from the parent spatter when the parent droplet strikes a target surface. blood spatter. a random distribution of blood stains that vary in size and that may be produced by a variety of mechanisms.
What blood stain pattern is created when blood is released or thrown from a blood bearing object?
Cast-Off Pattern
Why do blood drops not fly straight through the air?
The spherical shape is caused by the surface tension of the blood. Surface Tension causes the blood drop to pull itself in; both horizontally and vertically. The blood drop will settle into a spherical shape, as a result of the surface tension.
What is the fastest free falling blood can travel?
-the ration of the density of blood to the density (mass of the same unit volume) of water. –free falling blood will fall at a speed of 25.1 plus or minus 0.5 feet per second. -like all liquids, blood is held together by cohesive force producing a skin like surface resistant to penetration or separation.
What qualifies as a projected bloodstain?
Projected bloodstains are created when an exposed blood source is subjected to an action or force, greater than the force of gravity. The size, shape, and number of resulting stains will depend, primarily, on the amount of force utilized to strike the blood source.
What happens to the bloodstain pattern as the number of drops of blood increases?
The diameter of a bloodstain will increase as the distance that the blood drop falls increases until the acceleration of the drop remains constant and terminal velocity is reached. At terminal velocity the resulting stain size remains constant.
Do drop sizes affect this velocity?
How does the size of the source object/body part influence the size of a falling blood drop? Small drops have a lower terminal velocity and reach it after a short distance. The larger the drop the larger the terminal velocity.
What is the chemical that can be used to detect blood even if it has been cleaned up?
Fluorescein
What is the difference between forward spatter and back spatter?
Forward spatter is blood that travels away from the source in the same direction as the force that caused the spatter. Back spatter is blood directed back toward the source of the force that cause the spatter. Back spatter is more likely to be deposited on the object or person who was creating the impact.
What is blood spatter evidence?
(Courtesy of NFSTC) Bloodstain pattern analysis (BPA) is the interpretation of bloodstains at a crime scene in order to recreate the actions that caused the bloodshed. Analysts examine the size, shape, distribution and location of the bloodstains to form opinions about what did or did not happen.
Why is it called blood spatter and not splatter?
To spatter means to scatter small particles of a substance. A spatter is the pattern of drops that result from spattering. To splatter means to scatter large particles of a substance. A splatter is the pattern of drops that result from splattering.
What type of spatter creates the largest blood droplets?
LOW VELOCITY IMPACT: SPATTER THAT PRODUCES THE LARGEST BLOOD DROPLETS. PARENT DROP: DROP OF BLOOD THAT CASTS OFF A WAVE OR SATELLITE SPATTER. PLASMA: FLUID PORTION OF BLOOD, OBTAINED BY CENTRIFUGING A SAMPLE OF WHOLE BLOOD. COMPOSED OF 90% WATER, 10% METABOLITES.
What can dried blood tell an expert?
Patterns of drying help analysts determine how long an assault went on, detect whether it took place all at once or in stages, and nail down possible crime scene contamination [source: Wonder].
What component of the blood spatter indicates the direction of spray?
What component of the blood spatter indicates the direction of spray? The head of the bloodstain.
What is the original drop of blood that casts or gives off a satellite or wave called?
Parent Drop
What type of evidence is blood type?
Examples of class evidence include blood type, fibers, and paint. Individual Characteristics are properties of physical evidence that can be attributed to a common source with a high degree of certainty. Examples of individual evidence include anything that contains nuclear DNA, toolmarks, and fingerprints.
Which kind of blood stain develops due to gravity?
Drip Stain
What is a wipe pattern?
A wipe pattern is “An altered bloodstain pattern resulting from an object moving through a pre-existing wet bloodstain.”