Forensic science involves using scientific techniques for legal purposes, usually in criminal investigation and trial. Forensic science is a highly technical field, involving chemistry, biology, physics, metallurgy. and even engineering. Other fields that play part include geology. psychology, and social h science. Evidence, such as hair, fingerprints, or blood samples, is collected at the scene of the crime by forensic technicians. They try to match this evidence to a hopefully using a match to get a conviction. Then, suspect experienced forensic scientists, who often specialize in one forensic discipline, give the evidence in court as expert witness.