Forensic Metrology
Encyclopedia
Forensic metrology is metrology
, the science of measurement, as it applies to forensic sciences. Forensic laboratories
and criminalistic laboratories perform numerous measurements and tests to support both criminal and civil legal actions. Examples of forensic metrology include the measurement of blood or breath alcohol content, the quantification of controlled substance
s (both net weights and purity), and length measurements of firearm barrels
. The results of forensic measurements are used to determine if a person is charged with a crime or may be used to determine a statutory sentencing enhancement. Other examples of forensic metrology includes tests that measure if there is a presence of a substance (e.g., cocaine), latent print examination, questioned documents examination
, and DNA analysis.
Forensic measurements are all supported by reference standards which are traceable to the International System of Units
(SI) maintained by the International Bureau of Weights and Measures
, to natural constants, or to reference materials such as those provided by the United States' national metrology institute known as the National Institute of Standards and Technology
in Gaithersburg, Maryland
.
Examples of instruments and equipment used in forensic metrology include breathalyzer
s, balances & scales
, ruler
s, caliper
s, Gas chromotographers, and centrifuge
s.
Recent attention has been given to forensic metrology and metrological traceability as a result of an international effort to accredit forensic laboratories and criminalistic laboratories to the International Standards Organization 17025 requirements.
Metrology
Metrology is the science of measurement. Metrology includes all theoretical and practical aspects of measurement. The word comes from Greek μέτρον , "measure" + "λόγος" , amongst others meaning "speech, oration, discourse, quote, study, calculation, reason"...
, the science of measurement, as it applies to forensic sciences. Forensic laboratories
Laboratory
A laboratory is a facility that provides controlled conditions in which scientific research, experiments, and measurement may be performed. The title of laboratory is also used for certain other facilities where the processes or equipment used are similar to those in scientific laboratories...
and criminalistic laboratories perform numerous measurements and tests to support both criminal and civil legal actions. Examples of forensic metrology include the measurement of blood or breath alcohol content, the quantification of controlled substance
Controlled substance
A controlled substance is generally a drug or chemical whose manufacture, possession, or use are regulated by a government. This may include illegal drugs and prescription medications ....
s (both net weights and purity), and length measurements of firearm barrels
Gun barrel
A gun barrel is the tube, usually metal, through which a controlled explosion or rapid expansion of gases are released in order to propel a projectile out of the end at a high velocity....
. The results of forensic measurements are used to determine if a person is charged with a crime or may be used to determine a statutory sentencing enhancement. Other examples of forensic metrology includes tests that measure if there is a presence of a substance (e.g., cocaine), latent print examination, questioned documents examination
Questioned document examination
Questioned document examination is the forensic science discipline pertaining to documents that are in dispute in a court of law...
, and DNA analysis.
Forensic measurements are all supported by reference standards which are traceable to the International System of Units
International System of Units
The International System of Units is the modern form of the metric system and is generally a system of units of measurement devised around seven base units and the convenience of the number ten. The older metric system included several groups of units...
(SI) maintained by the International Bureau of Weights and Measures
International Bureau of Weights and Measures
The International Bureau of Weights and Measures , is an international standards organisation, one of three such organisations established to maintain the International System of Units under the terms of the Metre Convention...
, to natural constants, or to reference materials such as those provided by the United States' national metrology institute known as the National Institute of Standards and Technology
National Institute of Standards and Technology
The National Institute of Standards and Technology , known between 1901 and 1988 as the National Bureau of Standards , is a measurement standards laboratory, otherwise known as a National Metrological Institute , which is a non-regulatory agency of the United States Department of Commerce...
in Gaithersburg, Maryland
Gaithersburg, Maryland
Gaithersburg is a city in Montgomery County, Maryland, United States. The city had a population of 59,933 at the 2010 census, making it the fourth largest incorporated city in the state, behind Baltimore, Frederick, and Rockville...
.
Examples of instruments and equipment used in forensic metrology include breathalyzer
Breathalyzer
A breathalyzer or breathalyser is a device for estimating blood alcohol content from a breath sample...
s, balances & scales
Weighing scale
A weighing scale is a measuring instrument for determining the weight or mass of an object. A spring scale measures weight by the distance a spring deflects under its load...
, ruler
Ruler
A ruler, sometimes called a rule or line gauge, is an instrument used in geometry, technical drawing, printing and engineering/building to measure distances and/or to rule straight lines...
s, caliper
Caliper
A caliper is a device used to measure the distance between two opposing sides of an object. A caliper can be as simple as a compass with inward or outward-facing points...
s, Gas chromotographers, and centrifuge
Centrifuge
A centrifuge is a piece of equipment, generally driven by an electric motor , that puts an object in rotation around a fixed axis, applying a force perpendicular to the axis...
s.
Recent attention has been given to forensic metrology and metrological traceability as a result of an international effort to accredit forensic laboratories and criminalistic laboratories to the International Standards Organization 17025 requirements.