14 December 2014
Blood and Guns
The world of Forensic Scientist is an amazing and fascinating place. There are so many aspects that go into forensic science but in this paper we are only covering bloodstain spatter patterns. Bloodstain spatter patterns are not solely used to solve crimes but I do feel it is one of the most important. Bloodstains never lie.
A bullet is traveling at its fastest speed when it leaves the barrel of the gun. Bullets traveling after firing is said to be using kinetic energy. Kinetic energy is the energy the bullet has due to its motion from the firing pin striking the gun powder causing an explosion that forced the bullet to discharge from the barrel. Now this ...view middle of the document...
This mixture even in reduced size is still to explosive and needs stabilizers added. Stabilizers commonly used are diphenylamine and potassium sulfate (Warlow 67).
When you fire a gun not all of the powder will burn up and the powder left behind will leave a residue on your clothing or skin if you have fired the weapon or were standing close to a fired weapon. This residue will also be on your target if you are close to your target. This can help forensic scientist determine how far away from the target you were standing upon firing your weapon (Warlow 69-70). To determine if residue is on an individual forensic personal will use a scanning electron microscope (71-72).
Each gun barrel has what we like to call a signature. This means that when a bullet is fired from that gun it will leave behind striations unique to that weapon. This signature is actually made of imperfections with in the barrel or marks that occur over time. When examining a gun for a bullet striations match they will perform a test fire and this test can be performed in many ways. From shooting into a bullet proof case filled with gelatin material to shooting a bullet into water, either way you must fire the bullet into a material that will quickly and safely slow the bullets kinetic energy to avoid accidents within the forensic lab (Warlow 72-73).
We have internal and external ballistics. Internal ballistics is only concerned with the bullet while it remains in the barrel (Warlow 65). External ballistics deals with the bullet from the time it leaves the barrel until it hits its final target. External ballistics has much more ground to cover than internal. External ballistics deals with the bullets flight path, weather conditions that may affect the pathway of the bullet, and that basic law of gravity. Items that did not burn completely up upon the firing of the weapon will also be discharge and looked at under external ballistics. Sometime you have coal and wood pieces that will fly into your target and cause damage depending on how close you are standing (Warlow 81).
Depending on what the bullet hit will depend on the damage that is done. The bullet will so receive damage itself causing it to be deformed and sometime disintegrate depending on the target. Damage to the human body varies depending on where the bullet penetrates. Muscle will offer more resistance to the bullet versus fatty tissue or an organ such as the liver. If a bullet penetrates your lungs it will cause them to collapse. Bullets have also been known to bounce off a person’s ribs. Depending on what clothes you are wearing, like a heavy thick sheep skin jacket will have a tendency to help slow down the bullet but won’t stop it from penetrating the human body. There is no set rules of what will happen when you are shot. The closer the range to the intended target the more damage you will do. This is one reason suicide via gunshot wounds are so big (Warlow 109).
Upon arrival at a crime scene you will need...