Forensic science facts for kids
Forensic science (or forensics) is about collecting, preserving, and analyzing evidence at a place where a crime was committed. Samples commonly taken include fingerprints. People also look for other things that could be used, for example a few hairs (or pieces of skin). Samples like hair or skin can be use for DNA testing, which allows to tell the gender of the person the hair is from, amongst others. When someone is accused of committing the crime, these pieces of evidence can then be matched up. Then, if they are correct, the person is charged.
While some forensic scientists travel to the scene of the crime to collect the evidence themselves, others occupy a laboratory role, performing analysis on objects brought to them by other individuals. Others are involved in analysis of financial, banking, or other numerical data for use in financial crime investigation, and can be employed as consultants from private firms, academia, or as government employees.
In addition to their laboratory role, forensic scientists testify as expert witnesses in both criminal and civil cases and can work for either the prosecution or the defense.
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History
The ancient world lacked standardized forensic practices, which enabled criminals to escape punishment. Criminal investigations and trials relied heavily on forced confessions and witness testimony. However, ancient sources do contain several accounts of techniques that foreshadow concepts in forensic science developed centuries later.
The first written account of using medicine and entomology to solve criminal cases is attributed to the book of Xi Yuan Lu (translated as Washing Away of Wrongs), written in China in 1248 by Song Ci (宋慈, 1186–1249), a director of justice, jail and supervision, during the Song dynasty.
Song Ci introduced regulations concerning autopsy reports to court, how to protect the evidence in the examining process, and explained why forensic workers must demonstrate impartiality to the public. He devised methods for making antiseptic and for promoting the reappearance of hidden injuries to dead bodies and bones (using sunlight and vinegar under a red-oil umbrella); for calculating the time of death (allowing for weather and insect activity); described how to wash and examine the dead body to ascertain the reason for death. The book became the first form of literature to help determine the cause of death.
Methods from around the world involved saliva and examination of the mouth and tongue to determine innocence or guilt, as a precursor to the Polygraph test. In ancient India, some suspects were made to fill their mouths with dried rice and spit it back out. Similarly, in ancient China, those accused of a crime would have rice powder placed in their mouths. In ancient middle-eastern cultures, the accused were made to lick hot metal rods briefly. It is thought that these tests had some validity since a guilty person would produce less saliva and thus have a drier mouth; the accused would be considered guilty if rice was sticking to their mouths in abundance or if their tongues were severely burned due to lack of shielding from saliva.
In 16th-century Europe, medical practitioners in army and university settings began to gather information on the cause and manner of death. Ambroise Paré, a French army surgeon, systematically studied the effects of violent death on internal organs. Two Italian surgeons, Fortunato Fidelis and Paolo Zacchia, laid the foundation of modern pathology by studying changes that occurred in the structure of the body as the result of disease. In the late 18th century, writings on these topics began to appear. These included A Treatise on Forensic Medicine and Public Health by the French physician Francois Immanuele Fodéré and The Complete System of Police Medicine by the German medical expert Johann Peter Frank.
As the rational values of the Enlightenment era increasingly permeated society in the 18th century, criminal investigation became a more evidence-based, rational procedure − forced confessions was curtailed, and belief in witchcraft and other powers of the occult largely ceased to influence the court's decisions.
An article appearing in Scientific American in 1885 describes the use of microscopy to distinguish between the blood of two persons in a criminal case in Chicago.
Subdivisions
- Forensic accounting is the study and interpretation of accounting evidence
- Forensic anthropology is the application of physical anthropology in a legal setting, usually for the recovery and identification of skeletonized human remains.
- Forensic archaeology is the application of a combination of archaeological techniques and forensic science, typically in law enforcement.
- Computational forensics concerns the development of algorithms and software to assist forensic examination.
- Criminalistics applies various sciences to answer questions relating to examination and comparison of biological evidence, trace evidence, impression evidence (such as fingerprints, footwear impressions, and tire tracks), controlled substances, ballistics, firearm and toolmark examination, and other evidence in criminal investigations. In typical circumstances evidence is processed in a crime lab.
- Forensic dactyloscopy is the study of fingerprints.
- Digital forensics is the application of proven scientific methods and techniques in order to recover data from electronic / digital media. Digital Forensic specialists work in the field as well as in the lab.
- Forensic document examination or questioned document examination answers questions about a disputed document using a variety of scientific processes and methods. Many examinations involve a comparison of the questioned document, or components of the document, with a set of known standards. The most common type of examination involves handwriting, whereby the examiner tries to address concerns about potential authorship.
- Forensic DNA analysis takes advantage of the uniqueness of an individual's DNA to answer forensic questions such as paternity/maternity testing and placing a suspect at a crime scene.
- Forensic engineering is the scientific examination and analysis of structures and products relating to their failure or cause of damage.
- Forensic linguistics deals with issues in the legal system that requires linguistic expertise.
- Forensic pathology applies the medical methods and principles of pathology, including autopsy, to determine a cause of death or injury in the context of a legal inquiry.
- Forensic psychology is the study of the mind of an individual, using forensic methods. Usually it determines the circumstances behind a criminal's behavior.
- Forensic toxicology is the study of the effect of drugs and poisons on/in the human body.
- Forensic Podiatry is an application of the study of feet footprint or footwear and their traces to analyze scene of crime and to establish personal identity in forensic examinations.
Images for kids
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This is an example and explanation of extractor/ejector marks on casings.
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Apparatus for the arsenic test, devised by James Marsh
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Frontispiece from Bertillon's Identification anthropométrique (1893), demonstrating the measurements needed for his anthropometric identification system
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Fingerprints taken by William Herschel 1859/60
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Women clerical employees of the LA Police Department getting fingerprinted and photographed in 1928
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The popular fictional character Sherlock Holmes was in many ways ahead of his time in his use of forensic analysis.
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Alec Jeffreys invented the DNA profiling technique in 1984.
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See also
In Spanish: Criminalística para niños
