Criminalistics: Area of Convergence and Area of Origin
1. Explain the terms area of convergence and area of origin and explain what each term reveals to an investigator.
The area of convergence of an impact spatter pattern is the area the individual stains emanated from on a two-dimensional plane. The area of origin of a bloodstain pattern in three-dimensional space may represent the position of the victim or suspect when the stain-producing event took place. These areas can determine and reveal to an investigator the direction of force, angle of impact, and areas of origin. An area of origin determination should be calculated whenever possible. And also transfer patterns, created when an object with blood on it makes simple contact with surface, may reveal the shape or texture characteristics of the object. Because the direction of flows originating from either a single drop or a large amount of blood is caused by gravity, the direction of a pattern may suggest the original position of the surface when the flow was formed. 2. Explain the difference between forward spatter and back spatter and identify which is more likely to be deposited on the object of the person creating the impact.
Forward Spatter is Blood which travels in the same direction as the source of energy or force which caused the spatter. Sometimes back spatter is also known as blowback spatter. Whenever an object strikes the victim at a speed greater than 100 feet per second, high velocity blood spatter is the result. This kind of spatter tends to be very small and measures less than 1 mm in diameter. This spatter tends to be mist-like as though you took a spray bottle of red paint and sprayed a mist of paint on the wall. A speeding bullet could create a high velocity blood spatter pattern. Only around entrance and exit wounds do these patterns show up. Blood acts a bit differently whether the bullet is entering the body or leaving. Back spatter refers to spatter associated with an entrance wound. Sometimes back spatter is also known as blowback
The area of convergence of an impact spatter pattern is the area the individual stains emanated from on a two-dimensional plane. The area of origin of a bloodstain pattern in three-dimensional space may represent the position of the victim or suspect when the stain-producing event took place. These areas can determine and reveal to an investigator the direction of force, angle of impact, and areas of origin. An area of origin determination should be calculated whenever possible. And also transfer patterns, created when an object with blood on it makes simple contact with surface, may reveal the shape or texture characteristics of the object. Because the direction of flows originating from either a single drop or a large amount of blood is caused by gravity, the direction of a pattern may suggest the original position of the surface when the flow was formed. 2. Explain the difference between forward spatter and back spatter and identify which is more likely to be deposited on the object of the person creating the impact.
Forward Spatter is Blood which travels in the same direction as the source of energy or force which caused the spatter. Sometimes back spatter is also known as blowback spatter. Whenever an object strikes the victim at a speed greater than 100 feet per second, high velocity blood spatter is the result. This kind of spatter tends to be very small and measures less than 1 mm in diameter. This spatter tends to be mist-like as though you took a spray bottle of red paint and sprayed a mist of paint on the wall. A speeding bullet could create a high velocity blood spatter pattern. Only around entrance and exit wounds do these patterns show up. Blood acts a bit differently whether the bullet is entering the body or leaving. Back spatter refers to spatter associated with an entrance wound. Sometimes back spatter is also known as blowback