Bloodstain Pattern Analysis Part 2 Flashcards
bloodstain pattern analysis
the examination of the shapes, location, and distribution patterns of bloodstains, in order to provide an interpretation of the physical events that occurred at the crime scene
target surface
any surface (person, wall, object, etc.) that blood comes into contact with
what can a bloodstain analysis tell us?
-distsnce of blood source
-angle of impact of blood droplet
-determination of blood trail, their direction, and relative speed of motion
-nature of object used to cause the bloodshed, the # of blows involved, and relative location of person/objects
? of multiple blows
sequencing
to establish the position of a victim when reveing a ? impact
fatal
to corroborate or ? statements made by a suspect or witness
refute
to determine blood collection sites for DNA
DNA
types of fluid dynamics
cohesive forces, surface tension, viscosity
what is a cohesive force?
the attraction of like molecules to remain together as a unit
what is surface tension?
cohesive forces that cause a fluid to remain in the form of a sphere
what is viscosity?
the resistance of a fluid to flow freely
water = 1, blood = 3 to 6 times greater
size and force
force causes blood to break apart
the greater the force, the smaller the droplets
larger drops travel farther (tennis/ping pong ball)
size and distance
diameter of drop will increase with increased distance
shape of drop will change as
angle of impact increases
blood travels through the air as a
sphere
angle of impact
angle at which the blood drop hits the target surface as angle decreases the drop becomes more elongated
