What defines a passive bloodstain? Passive stains include
drops, flows and pools, and typically result from gravity acting on an injured body
. Transfer stains result from objects coming into contact with existing bloodstains and leaving wipes, swipes or pattern transfers behind such as a bloody shoe print or a smear from a body being dragged.
What are the 4 types of passive bloodstains?
- Passive. a. formed from the force of gravity acting alone. b. subdivided (drops, drip patterns, pools, clots) c. oozing or gushes from the body, dripping finger or arm, drops from a knife.
- Transfer. a. wet bloody surface comes in contact with a secondary surface. b. wipe, smudge, swipe or smear. c. …
- Projected blood spatter.
What defines a passive bloodstain quizlet?
What is the only force acting on a passive blood stain?
What qualifies as a projected bloodstain?
What is a passive drop and what is its shape?
Passive drops will
vary in shape and size depending on the volume of blood and the surface texture, but will generally be circular
. A bloodstain pattern which results from blood dripping into blood.
What shape are passive blood drops?
Passive Bloodstain Patterns. The fluid dynamics of dropping blood are responsible for the stains or patterns produced. The surface tension of the liquid blood causes the blood drops produced from a blood source to be
spherically shaped
.
How are passive drops formed?
Passive Drop (Bleeding) — Bloodstain drop(s) created or formed
by the force of gravity acting along
. Perimeter Stain — A bloodstain that consists of only its outer periphery, the central area having been removed by wiping or flaking after liquid blood has partially or completely dried.
What are the 3 types of blood stains?
Bloodstains are classified into three basic types:
passive stains, transfer stains and projected or impact stains
.
What are the 6 types of blood spatter?
There are seven bloodstain categories: (1) passive bloodstain; (2) projected bloodstains; (3) impact spatter; (4) cast-off bloodstains; (5) arterial gush or spurt bloodstains; (6) wipe bloodstain patterns; and (7) transfer bloodstains.
What four forces act on a blood droplet?
- Viscosity.
- Surface Tension.
- Droplet Flight Dynamics.
- The 4 Phases of Impact.
- Phase 1: Contact and Collapse.
- Phase 2: Displacement.
- Phase 3: Dispersion.
- Phase 4: Retraction.
What type of bloodstain is created when an object moves through an existing stain?
Wipe Pattern
– A bloodstain pattern created when an object moves through an existing stain, removing and/or altering its appearance.
What is the relationship between passive blood drop diameter and height?
As the distance of the fall increases, the diameter of the bloodstain will increase until it reaches a maximum diameter
. The maximum diameter for the bloodstain occurs after the drop has fallen approximately 1.8 m (6 ft). The volume of the drop of blood also affects the diameter of the bloodstain.
What is a drip stain blood?
Drip Stain –
A bloodstain resulting from a falling drop that formed due to gravity
. Drip Trail – A bloodstain pattern resulting from the movement of a source of drip stains between two points. Edge Characteristic – A physical feature of the periphery of a bloodstain.
How would a forensic investigator categorize this blood stain?
From what may appear to be a random distribution of bloodstains at a crime scene, analysts can categorize the stains by
gathering information from spatter patterns, transfers, voids and other marks that assist investigators in recreating the sequence of events that occurred after bloodshed
.
What is a skeletonized bloodstain?
A bloodstain pattern that can arise if a blood drop is allowed to partially dry and is then wiped
. Since the blood tends to be thinner at the edge of the drops, this portion dries first, leaving liquid in the middle.
What do fall droplets indicate?
When an object with blood on it touches one that does not have blood on it this produces?
What shape do blood droplets form when dropped vertically what factors lead to this formation?
What does the shape of a spatter stain determine?
Analysts can tell
the direction of the impacting object
by the shape of the spatter (tails point in the direction of motion). Counting the arcs can also show the minimum number of blows delivered. Arterial spray -‐ refers to the spurt of blood released when a major artery is severed.
What shape does blood have in flight?
What weapon causes transfer of blood?
High velocity blood spatter:
High velocity blood spatter is usually caused by
a gunshot
, it can also be caused by other objects too if enough force is exerted. The force of the blood hitting a surface for high velocity blood spatter is over 100 feet per second.
Which of the following is formed when blood collects on a level undisturbed surface?
What is the most common type of bloodstain pattern found at a crime scene?
The most common type of bloodstain pattern found at a crime scene is
impact spatter
. The pattern occurs when an object impacts the source of the blood. Spatter projected outward and away from the source, such as an exit wound, is called forward spatter.
What are two phases of bloodstain pattern interpretation?
Bloodstain pattern analysis is performed in two phases:
pattern analysis and reconstruction
.
What is a drag blood pattern?
Transfer Stains:
These occur by objects or surroundings coming into contact with the blood
. These can be drag marks, cloth patterns, shoe/footprints, handprints, fingerprints, wipes and swipes. Projected/Impact stains: These occur by the blood that travelled in the air.
What are the 4 basic types of blood?
What is stippling and internal muzzle staining?
Stippling
.
Burns or gunpowder on a victims skin from a gunshot at close range
.
Internal muzzle staining
.
When explosive gases from a gunshot cause blood to be pulled into the muzzle of a gun
.
What is a parent drop?
What are the 4 phases of impact?
What do cohesive forces do in blood droplets?
Cohesion is a force that acts within a drop of blood (or any liquid) that
gives the liquid certain properties such as surface tension
. It allows molecules within the blood drop to resist separation and causes a blood drop to form a distinctive tear shape characteristic of this force (see Fig. 8.2).
What are 5 things that blood spatter can tell us?
What is it called when blood dries?
During the
coagulation (clotting) process
, fibrin strands are formed creating a solid structure of the blood, the clot. During drying water evaporates from the blood pool until only the solid matter, mainly red blood cells (RBC’s), remains.
Which type of spatter is likely to be deposited on the object or person creating the impact?
Back spatter
is more likely to be deposited on the object or person creating the impact.
What are the four types of passive blood stains?
- Passive. a. formed from the force of gravity acting alone. b. subdivided (drops, drip patterns, pools, clots) c. oozing or gushes from the body, dripping finger or arm, drops from a knife.
- Transfer. a. wet bloody surface comes in contact with a secondary surface. b. wipe, smudge, swipe or smear. c. …
- Projected blood spatter.
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
.
