Measurement

thumb|upright|Four measuring devices having metric calibrations Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events. In other words, measurement is a process of determining how large or small a physical quantity is as compared to a basic reference quantity of the same kind. The scope and application of measurement are dependent on the context and discipline. In natural sciences and engineering, measurements do not apply to nominal properties of objects or events, which is consistent with the guidelines of the Internat

thumb|upright=1.05|A modern instrument for geodetic measurements using satellites

thumb|The National Institute of Standards and Technology|NIST-4 [[Kibble balance, which is used to measure weight via electric current and voltage. With this instrument, the measurement of mass is no longer dependent on a defined mass standard and is instead dependent on natural physical constants.]] Metrology is the scientific study of measurement. It establishes a common understanding of units, crucial in linking human activities. Modern metrology has its roots in the French Revolution's political motivation to standardise units in France when a length standard taken from a natural source wa

An error (from the Latin , meaning 'to wander') is an inaccurate or incorrect action, thought, or judgement.

Quantity or amount is a property that includes numbers and quantifiable phenomena such as mass, time, distance, heat, angle, and information. Quantities can commonly be compared in terms of "more", "less", or "equal", or by assigning a numerical value multiple of a unit of measurement. Quantity is among the basic classes of things along with quality, substance, change, and relation. Some quantities are such by their inner nature (as number), while others function as states (properties, dimensions, attributes) of things such as heavy and light, long and short, broad and narrow, small and great,

reference values for temperature and pressure

ratio of a distance on the map to the corresponding distance on the ground

thumb|Situations often arise wherein a decision must be made when the results of each possible choice are uncertain.

method of writing numbers, especially very large or small ones

thumb|right|240px|The field of ergonomics employs anthropometry to optimize human interaction with equipment and workplaces.

alt=A set of number blocks. The blocks 1, 2, and 3 are in the foreground; six other blocks can be seen in the background|thumb|Number blocks, which can be used for counting Counting is the process of determining the number of elements of a finite set of objects; that is, determining the size of a set. The traditional way of counting consists of continually increasing a (mental or spoken) counter by a unit for every element of the set, in some order, while marking (or displacing) those elements to avoid visiting the same element more than once, until no unmarked elements are left; if the counte

thumb|An expendable dropsonde used to capture weather data. The telemetry consists of sensors for pressure, temperature, and humidity and a wireless transmitter to return the captured data to an aircraft. thumb|300px|A saltwater crocodile with a GPS-based satellite transmitter attached to its head for tracking Telemetry is the in situ collection of measurements or other data at remote points and their automatic transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Greek roots tele, 'far off', and metron, 'measure'. Systems that need external instr

In measurement technology and metrology, calibration is the comparison of measurement values delivered by a device under test with those of a calibration standard of known accuracy. Such a standard could be another measurement device of known accuracy, a device generating the quantity to be measured such as a voltage, a sound tone, or a physical artifact, such as a meter ruler.

collection of units of measurement and rules relating them to each other

thumb|upright=1.5|Comparison of photometric and radiometric quantities Radiometry is a set of techniques for measuring electromagnetic radiation, including visible light. Radiometric techniques in optics characterize the distribution of the radiation's power in space, as opposed to photometric techniques, which characterize the light's interaction with the human eye.

measure comparing the level of a searched signal to the level of background noise

auxiliary scale of a measurement device, that aids to increase measurement precision

classification that describes the nature of information within the numbers assigned to variables

measure of probability that a specific process will take place in a collision of two particles

analysis of the relationships between different physical quantities by identifying their base quantities and units of measure

symbol placed before units of digital information to indicate multiplication by a power of two

Reproducibility, closely related to replicability and repeatability, is a major principle underpinning the scientific method. For the findings of a study to be reproducible means that results obtained by an experiment or an observational study or in a statistical analysis of a data set should be achieved again with a high degree of reliability when the study is replicated. There are different kinds of replication but typically replication studies involve different researchers using the same methodology. Only after one or several such successful replications should a result be recognized as sci

drinking vessel

parameter characterizing the dispersion of quantity values of a measurand

thumb|Chromaticity Diagram of the LCH color space

small tumbler

statistic expressing the amount of random sampling error in a survey's results

set of pseudo units to describe small values of miscellaneous dimensionless quantities

published ISO standard series

thumb|180px|Gold dinar of Umayyad Caliph [[Abd al-Malik ibn Marwan, minted at Damascus, Syria in AH 75 (697/698 CE), having a weight of almost 1 mithqāl (5 grams)]]

In physics, an observable is a physical property or physical quantity that can be measured. In classical mechanics, an observable is a real-valued "function" on the set of all possible system states, e.g., position and momentum. In quantum mechanics, an observable is described by a linear operator. For example, these operators might represent submitting the system to various electromagnetic fields and eventually reading a value.

technique of measuring animal feed contents

international standard

Refractometry is the analytical method of measuring substances' refractive index (one of their fundamental physical properties) in order to, for instance, assess their composition or purity. A refractometer is the instrument used to measure refractive index ("RI"). Although refractometers are best known for measuring liquids, they are also used to measure gases and solids, such as glass and gemstones.

for a given analytical procedure, concentration or quantity derived from the smallest measure that can be detected with reasonable certainty

Turbidimetry (the name being derived from turbidity) is the process of measuring the loss of intensity of transmitted light due to the scattering effect of particles suspended in it. Light is passed through a filter creating a light of known wavelength which is then passed through a cuvette containing a solution. A photoelectric cell collects the light with a spectrophotometer or a photometer, which passes through the cuvette. A measurement is then given for the amount of absorbed light.

method for a test in science or engineering; definitive procedure that produces a test result; technical operation or procedure that consists of determination of characteristics of a given product,process or service according to a specified procedure

flat-bottomed drinking glass

systems design and implementation with a view to maximising service

unit of volume with different values

unit of measurement adopted by convention for a base quantity

A device used to make non-contact vibration measurement of a surface using a beam of light.

system of quantities based on seven base quantities: length, mass, time, electric current, thermodynamic temperature, amount of substance, and luminous intensity

measure of frequency stability in clocks and oscillators

quantity of process intensivity (mathematics)

systematic collection of information about a forested area for assessment or analysis

Chronostasis (from Greek , , 'time' and , , 'standing') is a type of temporal illusion in which the first impression following the introduction of a new event or task-demand to the brain can appear to be extended in time. For example, chronostasis temporarily occurs when fixating on a target stimulus, immediately following a saccade (i.e., quick eye movement). This elicits an overestimation in the temporal duration for which that target stimulus (i.e., postsaccadic stimulus) was perceived. This effect can extend apparent durations by up to half a second and is consistent with the idea that the

analyzing a real-world object or environment to collect data on its shape and possibly its appearance (e.g. colour)

The cross-sectional area of tree stems usually reported as the sum of all trees within a stand on a relative area basis

method to measure velocities in fluid

an animal's bite force per body mass, measured in newtons per kilogram

quantification of bulk fluid movement

parameter quantifying the uncertainty of a perturbed orbital solution for a minor planet

optical method of measuring fluid flow

qualitative or quantitative procedure designed to detect presence of, or quantify, a chemical compound or group

Porosimetry is an analytical technique used to determine various quantifiable aspects of a material's porous structure, such as pore diameter, total pore volume, surface area, and bulk and absolute densities.

the sampling frequency of a digital audio device

Morphometric measurement used in herpetology

standards used to check the quality and metrological traceability of products