Forensic Photography And Crime Scene example essay topic

Forensic Science Forensic Science is the application of chemistry to the investigation of crime. It includes firearms and toolmark identification, forensic psychiatry and profiling, questioned document examination, criminal law, personal identification, forensic photography and crime scene processing. They analyze things like hair, fiber, body fluids, bullets, paint, soil, glass, shoe impressions, fingerprints, drugs, and plant material. Their work is not only limited to crimes against individuals, such as homicide, theft, fraud, and arson. Food adulteration, environmental pollution, use and distribution of unsafe chemicals, and dangerous working conditions are also some crimes against society that Forensic Chemists are involved in.

DNA is used in Forensic Chemistry by retrieving the genetic code from evidence left on a crime scene. DNA is material that determines eye color, hair color, stature, bone density and many other human and animal traits. DNA is a long but narrow string-like object and is constructed like a ladder that has been grabbed at both ends and twisted, creating the double helix shape. There are four bases that form the rungs of the ladder: Cytocene, Guanine, Thiamine and Adnine. They are always in pairs and always complement each other.

Cytocene is always paired with Guanine and Thiamine is always paired with Adnine. Each base forms half of the rung, meeting in the middle. When DNA replicates, is unzips down the middle, splitting the base pairs. The complementary bases now attach to the opened segments to make new DNA. Fingerprints are the classic means of establishing that a person was at the scene of a crime. Fingerprints are Friction ridges that contain rows of sweat pores.

Sweat mixed with other body oils and dirt produces fingerprints on smooth surfaces. There are three basic fingerprint patterns: Loops, Arches and Whorls. Everyone falls into one of these three patterns. These patterns are called minutae points. There are about thirty different types of minutae points, and no two people have the same types of minutae in the same number in the same places on their fingertips. This is the reason why our fingerprints are very unique.

Fingerprint experts use powders and chemicals to be able to see these prints. The visibility of a set of prints depends on the surface from which they " re lifted, but with the help of computer enhancement techniques that can project a complete pattern from very little fragments, and laser technology that can read almost invisible markings, fingerprint experts can retrieve identifiable prints from most surfaces. If there was a firearm or tool used in the scene scientists also use firearms and toolmark identification to retrieve more evidence. Firearms examination involves the finding of characteristics between firearm and projectile, projectile and target. This includes matching the gun that was fired to the bullet (s). Rifling gives the bullet a signature marking that is unique to the weapon that fired it.

Rifling consists of lands and groves that expand the soft lead into the lands and groves when the gunpowder in the cartridge is ignited. Microscopic scratches from the lands and grooves mark the bullet which makes it unique to a particular firearm. The scratch marks on the bullet match the scratch marks in the barrel of the gun that fired it, to the exclusion of all other weapons. The test-fired bullet is compared under a comparison microscope, side by side, to the bullet recovered from the crime scene. Toolmark identification involves the identifying characteristics between tools, such as a pry bar, and the object on which it is used, such as a doorframe. Also included in the category are explosives and imprint evidence.

There are three types of toolmark impressions: Compression, where a tool surface presses into a softer material; Sliding, in which a tool scrapes across a surface causing parallel scratches; and cutting, which is a combination of the above two types. All three types can yield class and individual characteristics. Frequently, the evidence that is most incriminating is so small that the perpetrator is oblivious to it. That's why we need forensic scientists. There are many other aspects to forensic science, but these are some of the major ones.

It's amazing what these people can do with such little they have.