Blood Spatter Effect

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There are four phases of blood spatter impact, which one is the contact or collapse. This droplet makes contact with the target surface and collapses from the bottom up. The part of the blood drop, that have not yet collided with the surface, will remain as a sphere. Displacement is another phase of blood spatter impact, which the blood drop, collapses against the target surface and nearly all of the blood has moved from the center of the droplet, to the rim. The area of displacement phase, will remain the same size as the result bloodstain. (Blood Spatter, Properties of Blood). (Nod)The Dispersion phase occurs, when most of the blood is forced into the rim. The spines will continue to increase upward and in a direction opposite to the original…show more content…
The retraction phase, is the last phase from the effect of the surface tension attempting to pull the blood drop back. The forces trying to pull the blood drop apart are overcome by surface tension, resulting in the stain to be shaped in a circular and symmetrical position. If the forces pulled the blood drop away and overcome the surface tension, the blood drop will burst and will create irregular stain pattern. (Blood Spatter, Properties of Blood). (n.d) The force, velocity and blood drop size, the size and appearance of the bloodstain will depend on the force that was used to create them. When an item comes in contact with the blood, the force of the object moves the blood. At a crime scene, there could be evidence of low, medium or high velocity blood spatter or a combination of all the velocities. A low velocity force is the result of blood dripping from a person who is maybe still, walking, or running. Blood drops may be free falling and only moving due to the force of gravity. At low velocities forces, larger bloodstains are produced. In some cases low velocity bloodstains result in a weapon cast-off of blood dripping from a victim or…show more content…
Crime scene analysts can determine the direction in which the blood droplet traveled. The blood drop will remain consistent until it hit its point or surface. (Blood Spatter, Properties of Blood). (n.d)When the drop hits its target, the blood moves outwards during the collapse phase creating either an elliptical or circular stain. The long axis will provide an indication of the traveled distance of the blood drop. After the directionality of several bloodstains has been determined, an area or point of convergence may be established by simply drawing straight lines through the long axes of the bloodstains. (Blood Spatter, Properties of Blood). (n.d) the areas where these lines converge represents the relative location of the blood source in a two-dimensional perspective on the x-and y-axes. The area of origin or the location of the blood source in a three-dimensional perspective can also be determined. By establishing the impact angles of representative bloodstains and projecting their trajectories back to common axis, an approximate location of where the blood source was when it was impacted may be established. The angle of impact has a relationship between length and width of a bloodstain and the angle at which the droplet impacts on a

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