Bloodstain pattern analysis {with 100% Verified Solutions}

Define bloodstain pattern analysis correct answers the study and analysis of bloodstains at a known or suspected crime scene with the purpose of drawing conclusions about the nature, timing and other details of the crime. It is one of the several specialties of forensic science. The use of bloodstains as evidence is not new Define cohesive and disruptive forces and provide examples of each correct answers Cohesive - blood sticks to these surfaces very well and tends to hold its shape. Disruptive - blood does not stick to these surfaces very well and does not hold its shape How did investigators previously view how blood droplets interact with a target surface correct answers Typically they just took it as it was. There were no further investigations to try to determine the physics of the situation, the angle of impact nor what type of spatter it actually was (low, medium or high velocity) What is the current understanding of droplets interact with a target surface and how do know this correct answers It's based completely off of the cohesiveness of the surface the blood interacts with. Since different surfaces have different levels of cohesiveness and there are various disruptive forces at play, blood droplets will behave differently List the five mechanisms of blood pattern types correct answers Type of Stain, Bloodshed Events, Patterns, How it's collected, Who/Where/When Collected. How long does it take for a droplet to achieve a Spherical shape correct answers This is really a trick question as it depends on a few things: humidity level, "thickness" of the blood, cohesive factors as well as the surface the blood falls on List the four impact phases of a droplet correct answers Contact/Collapse, Displacement, Dispersion, Retraction What is the motion of the blood droplets in the first phase correct answers The droplet contacts the target surface and collapses from the bottom up. The part of the drop that has not yet collided with the surface remains as part of the sphere. As the collapse occurs, the blood that has come in contact with the surface is forced outward creating a rim. The rim gets bigger as more of the droplet comes in contact with the surface and more blood is forced into the rim. What is the motion of the droplet in phase 4 correct answers The last phase results from the effect of surface tension attempting to pull the droplet back. If the forces trying to pull the droplet apart are overcome by surface tension, the resulting stain will be reasonably circular and symmetrical in shape. If the forces pulling the droplet apart overcome the surface tension, the droplet will 'burst' and create an irregular stain pattern.