"Oh, how simple it would all have been had I been here before they came like a herd of buffalo and wallowed all over it." .
-A. Conan Doyle.
Forensic science is the combining of science with law. It is like a puzzle. You try to find different pieces of the puzzle that show you what happened. Forensic science is mainly used to investigate crimes such as assault, rape, kidnapping, robbery and murder. That is why protecting a crime scene is so important. There are many different techniques used in forensics.
Ballistics is the science that deals with the motion of objects and the conditions that affect the motion. It is used a lot today for criminal investigations that deal with firearms and bullets. When guns are made, they each have a unique spiral groove engraved into the gun barrel. When the gun is shot, the grooves leave imprints on the bullet called striations and no two guns make the same striations. Ballistic experts can determine if a bullet was shot from a particular gun by its striations. The barrel is not the only part of the gun that leaves identifying marks on the bullets. When a bullet is fired, its casing jerks back against the breech face of the gun. Any imperfection on the breech face gets impressed on the case head. Another factor in ballistics is impact. A bullet that strikes human bone or any hard object can have its shape altered. That is why it is more reliable to conduct tests with casings taken from a crime scene rather than just using regular bullets. A bullet consists of a casing with a soft metal cap holding the primer charge. When the bullet is struck by the firing pin, the primer inside ignites and shoots the bullet from the gun, leaving the case behind. Old black powder bullets used to leave distinctive marks on the hands of the person firing the weapon and around the wound of a person that was shot. A modern smokeless powder bullet leaves a residue on the hands of the person who fired the weapon that can only be detected by chemical testing.