Definition

Definition: The study of evidence discovered at a crime scene and used in a court of law.
Context: The author of the Sherlock Holmes stories, Sir Arthur Conan Doyle, was also responsible for furthering the work of forensic science by applying the principles of fingerprinting and firearm identification to criminal investigation work.

Forensic science is any science used for the purposes of the law, and therefore provides impartial scientific evidence for use in the courts of law, and in a criminal investigation and trial. Forensic science is a multidisciplinary subject, drawing principally from chemistry and biology, but also from physics, geology, psychology, social science, etc.

In a typical criminal investigation crime-scene investigators, sometimes known as scene-of-crime officers, will gather material evidence from the crime scene, victim and/or suspect. Forensic scientists will examine these materials to provide scientific evidence to assist in the investigation and court proceedings, and thus work closely with the police. Senior forensic scientists, who usually specialize in one or more of the key forensic disciplines, may be required to attend crime scenes or give evidence in court as impartial expert witnesses.

Examples of forensic science include the use of gas chromatography to identify seized drugs, DNA profiling to help identify a murder suspect from a bloodstain found at the crime scene, and laser Raman spectroscopy to identify microscopic paint fragments.

From examining hair follicles in a lab to scouring a crime scene looking for left behind clues, forensics is a big part of the crime world. It happens every day. It can be a little complicated but great minds have found true suspects. It revolves around evidence. That can include:

Type	Image	Description
Blood samples		Common sense..the blood left behind at a crime scene will reveal a person's blood type and possibly their identity.
Fingerprints		They are sorted into different categories and therefore reduce the number of suspects.
Footprints/Shoe prints		Strangely enough, footprints and shoe prints in sand and soft ground can tell about a person's shoe size and what type of shoe they wear. From there, they narrow down the number of people who have bought those type of shoes.
Hair Follicles		A single hair strand left at the scene can show a person's DNA, which is one of a kind, and could tell you everything about a person.
Vehicles		Sometimes the car at the scene of the crime will try to be hidden, but when found, can be traced by a license number and the make and model to the person who purchased the vehicle.
Dust, dirt, etc	N/A	Dirt and dust could provide DNA also.
Semen, body fluids	N/A	These important clues, especially in assault cases will determine directly who a criminal is, simply by DNA.
Little things such as cigarette buds, candy wrappers, etc		This is also a good clue to DNA evidence.

You may be wondering what DNA is, after reading about it in the above diagram. DNA is a long fiber, like a hair, only thinner and longer. It is made from two strands that stick together with a slight twist. It looks like this:

A revolution has occurred in the last few decades that explains how DNA makes us look like our parents and how a faulty gene can cause disease. This revolution opens the door to curing illness, both hereditary and contracted. The door has also been opened to an ethical debate over the full use of our new knowledge. In the end, curiosity is the reason to learn about DNA. Fittingly, curiosity is the driving force behind science itself.