Measurement is the determination of the size or magnitude of something. Measurement is not limited to physical quantities, but can extend to quantifying almost any imaginable thing such as degree of uncertainty, consumer confidence, or the rate of increase in the fall in the price of beanie babies.
- "A measurement is a comparison to a standard." -- William Shockley
Metrology is the study of measurement.
A metric is a standard for measurement. The quantification of phenomena through the process of measurement relies on the existence of an explicit or implicit metric, which is the standard to which the measure is referenced. If I say I am '5', I am indicating a measurement without conveying an applicable standard. I may mean I am 5 years old, 5 feet high, or 5-time world raquetball champion.
Measuring physical quantities accurately is important in science, engineering and commerce.
For example, the unit for length might be a well-known person's foot, and the length of a boat can be given as the number of times that person's foot would fit the length of the boat.
Laws to regulate measurement were originally developed to prevent fraud. However, units of measurement are now generally defined on a scientific basis, and are established by international treaties.
The history of measurements is a topic within the History of Science and Technology. The meter was standardized as the unit for length after the French revolution, and has since been adopted throughout most of the world. The United States and the UK are in the process of converting to the SI system. This process is known as metrication.
Systems of measurement:
- Imperial units
- SI system, also known as the metric system
- Chinese units
Some important physical quantities include:
- the speed of light
- the fine-structure constant
- the charge of an electron
In economics, a unit of account is a basis for measuring a market.
See also:
- Weights and measures
- Historical weights and measures
- Timeline of time measurement technology
- Timeline of temperature and pressure measurement technology
- Dimensional analysis
- Dimensionless number
- conversion of units
- orders of magnitude
- league
External Links
- There is A Dictionary of Units of Measurement of all kinds at http://www.unc.edu/~rowlett/units/index.html