Forensic science is the application of scientific techniques in collecting and analyzing physical evidence in criminal cases. 1 Forensic science has really advanced over the years. The first recorded application of medical knowledge to the solution of a crime was in a Chinese book, His Duan Yu (the washing away of wrongs), written in 1248. It contains a description of how to distinguish drowning and strangulation. These days, we have ways of telling whether the person was drowned intentionally or not and if their strangulation was accidental or a murder.
There are many branches to the world of forensic science. There are: firearms and tool mark identification, forensic psychiatry and profiling, criminal law, personal identification, forensic photography, and crime scene processing. These all require deferent scientists to do, because of how long it takes to do the work. A crime may have as many as ten forensic experts looking for evidence and examining it.
First let's look at firearm identification. Physical evidence has two main parts: class characteristics and individual characteristics.
"Class characteristics are characteristics that are common to a group of similar objects. For example, someone buys a p