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A measuring instrument is a device to measure a
physical quantity A physical quantity is a physical property of a material or system that can be quantified by measurement. A physical quantity can be expressed as a ''value'', which is the algebraic multiplication of a ' Numerical value ' and a ' Unit '. For examp ...
. In the
physical science Physical science is a branch of natural science that studies non-living systems, in contrast to life science. It in turn has many branches, each referred to as a "physical science", together called the "physical sciences". Definition Phys ...
s, quality assurance, and
engineering Engineering is the use of scientific method, scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompasses a broad rang ...
, measurement is the activity of obtaining and comparing
physical quantities A physical quantity is a physical property of a material or system that can be quantified by measurement. A physical quantity can be expressed as a ''value'', which is the algebraic multiplication of a ' Numerical value ' and a ' Unit '. For examp ...
of real-world objects and events. Established standard objects and events are used as units, and the process of measurement gives a number relating the item under study and the referenced unit of measurement. Measuring instruments, and formal
test method A test method is a method for a test in science or engineering, such as a physical test, chemical test, or statistical test. It is a definitive procedure that produces a test result. In order to ensure accurate and relevant test results, a test ...
s which define the instrument's use, are the means by which these relations of numbers are obtained. All measuring instruments are subject to varying degrees of instrument error and
measurement uncertainty In metrology, measurement uncertainty is the expression of the statistical dispersion of the values attributed to a measured quantity. All measurements are subject to uncertainty and a measurement result is complete only when it is accompanied by ...
. These instruments may range from simple objects such as
ruler A ruler, sometimes called a rule, line gauge, or scale, is a device used in geometry and technical drawing, as well as the engineering and construction industries, to measure distances or draw straight lines. Variants Rulers have long ...
s and
stopwatch A stopwatch is a timepiece designed to measure the amount of time that elapses between its activation and deactivation. A large digital version of a stopwatch designed for viewing at a distance, as in a sports stadium, is called a stop clock. ...
es to
electron microscope An electron microscope is a microscope that uses a beam of accelerated electrons as a source of illumination. As the wavelength of an electron can be up to 100,000 times shorter than that of visible light photons, electron microscopes have a ...
s and
particle accelerator A particle accelerator is a machine that uses electromagnetic fields to propel electric charge, charged particles to very high speeds and energies, and to contain them in well-defined particle beam, beams. Large accelerators are used for fun ...
s. Virtual instrumentation is widely used in the development of modern measuring instruments.


Time

In the past, a common time measuring instrument was the
sundial A sundial is a horological device that tells the time of day (referred to as civil time in modern usage) when direct sunlight shines by the apparent position of the Sun in the sky. In the narrowest sense of the word, it consists of a fl ...
. Today, the usual measuring instruments for time are
clock A clock or a timepiece is a device used to measure and indicate time. The clock is one of the oldest human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month and t ...
s and
watch A watch is a portable timepiece intended to be carried or worn by a person. It is designed to keep a consistent movement despite the motions caused by the person's activities. A wristwatch is designed to be worn around the wrist, attached ...
es. For highly accurate measurement of time an
atomic clock An atomic clock is a clock that measures time by monitoring the resonant frequency of atoms. It is based on atoms having different energy levels. Electron states in an atom are associated with different energy levels, and in transitions betw ...
is used.
Stopwatch A stopwatch is a timepiece designed to measure the amount of time that elapses between its activation and deactivation. A large digital version of a stopwatch designed for viewing at a distance, as in a sports stadium, is called a stop clock. ...
es are also used to measure time in some sports.


Energy

Energy is measured by an energy meter. Examples of energy meters include:


Electricity meter

An
electricity meter North American domestic analog electricity meter. Electricity meter with transparent plastic case (Israel) North American domestic electronic electricity meter An electricity meter, electric meter, electrical meter, energy meter, or kilowa ...
measures energy directly in
kilowatt-hour A kilowatt-hour ( unit symbol: kW⋅h or kW h; commonly written as kWh) is a unit of energy: one kilowatt of power for one hour. In terms of SI derived units with special names, it equals 3.6 megajoules (MJ). Kilowatt-hours are a common bi ...
s.


Gas meter

A
gas meter A gas meter is a specialized flow meter, used to measure the volume of fuel gases such as natural gas and liquefied petroleum gas. Gas meters are used at residential, commercial, and industrial buildings that consume fuel gas supplied by a g ...
measures energy indirectly by recording the volume of gas used. This figure can then be converted to a measure of energy by multiplying it by the
calorific value The heating value (or energy value or calorific value) of a substance, usually a fuel or food (see food energy), is the amount of heat released during the combustion of a specified amount of it. The ''calorific value'' is the total energy rele ...
of the gas.


Power (flux of energy)

A
physical system A physical system is a collection of physical objects. In physics, it is a portion of the physical universe chosen for analysis. Everything outside the system is known as the environment. The environment is ignored except for its effects on the ...
that exchanges energy may be described by the amount of energy exchanged per time- interval, also called power or
flux Flux describes any effect that appears to pass or travel (whether it actually moves or not) through a surface or substance. Flux is a concept in applied mathematics and vector calculus which has many applications to physics. For transport ...
of energy. *(see any measurement device for power below) For the ranges of power-values see:
Orders of magnitude (power) This page lists examples of the power in watts produced by various sources of energy. They are grouped by orders of magnitude from small to large. Below 1 W 1 to 102 W 103 to 108 W The productive capacity of electrical generators oper ...
.


Action

Action describes energy summed up over the time a process lasts (time
integral In mathematics, an integral assigns numbers to functions in a way that describes displacement, area, volume, and other concepts that arise by combining infinitesimal data. The process of finding integrals is called integration. Along with ...
over energy). Its
dimension In physics and mathematics, the dimension of a mathematical space (or object) is informally defined as the minimum number of coordinates needed to specify any point within it. Thus, a line has a dimension of one (1D) because only one coor ...
is the same as that of an
angular momentum In physics, angular momentum (rarely, moment of momentum or rotational momentum) is the rotational analog of linear momentum. It is an important physical quantity because it is a conserved quantity—the total angular momentum of a closed sy ...
. *A phototube provides a voltage measurement which permits the calculation of the quantized action (
Planck constant The Planck constant, or Planck's constant, is a fundamental physical constant of foundational importance in quantum mechanics. The constant gives the relationship between the energy of a photon and its frequency, and by the mass-energy equivalen ...
) of light. (See also
Photoelectric effect The photoelectric effect is the emission of electrons when electromagnetic radiation, such as light, hits a material. Electrons emitted in this manner are called photoelectrons. The phenomenon is studied in condensed matter physics, and solid stat ...
.)


Geometry


Dimensions (size)


Length (distance)

* Length, distance, or range meter For the ranges of length-values see:
Orders of magnitude (length) The following are examples of orders of magnitude for different lengths. __TOC__ Overview Detailed list To help compare different orders of magnitude, the following list describes various lengths between 1.6 \times 10^ metres and 10 ...


Area

*
Planimeter A planimeter, also known as a platometer, is a measuring instrument used to determine the area of an arbitrary two-dimensional shape. Construction There are several kinds of planimeters, but all operate in a similar way. The precise way in whic ...
For the ranges of area-values see: Orders of magnitude (area)


Volume

*
Buoyant weight Buoyancy (), or upthrust, is an upward force exerted by a fluid that opposes the weight of a partially or fully immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus the pr ...
(solids) *
Eudiometer A eudiometer is a laboratory device that measures the change in volume of a gas mixture following a physical or chemical change. Description Depending on the reaction being measured, the device can take a variety of forms. In general, it is s ...
,
pneumatic trough A pneumatic trough is a piece of laboratory apparatus used for collecting gases, such as hydrogen, oxygen and nitrogen.It is mainly made of glass or various fibres and are of various sizes.It was invented by Stephen Hales. Description Four ...
(gases) *
Flow measurement Flow measurement is the quantification of bulk fluid movement. Flow can be measured in a variety of ways. The common types of flowmeters with industrial applications are listed below: * a) Obstruction type (differential pressure or variable area) ...
devices (liquids) *
Graduated cylinder A graduated cylinder, also known as a measuring cylinder or mixing cylinder, is a common piece of laboratory equipment used to measure the volume of a liquid. It has a narrow cylindrical shape. Each marked line on the graduated cylinder represent ...
(liquids) *
Measuring cup A measuring cup is a kitchen utensil used primarily to measure the volume of liquid or bulk solid cooking ingredients such as flour and sugar, especially for volumes from about 50  mL (2  fl oz) upwards. Measuring cups are also use ...
(grained solids, liquids) *
Overflow trough Overflow may refer to: Computing and telecommunications * Integer overflow, a condition that occurs when an integer calculation produces a result that is greater than what a given register can store or represent * Buffer overflow, a situation wher ...
(solids) *
Pipette A pipette (sometimes spelled as pipett) is a laboratory tool commonly used in chemistry, biology and medicine to transport a measured volume of liquid, often as a media dispenser. Pipettes come in several designs for various purposes with dif ...
(liquids) If the mass density of a solid is known, weighing allows to calculate the volume. For the ranges of volume-values see: Orders of magnitude (volume)


Angle

* Circumferentor * Cross staff *
Goniometer A goniometer is an instrument that either measures an angle or allows an object to be rotated to a precise angular position. The term goniometry derives from two Greek words, Wikt:γωνία, γωνία (''gōnía'') 'angle' and Wikt:μέτρο ...
* Graphometer *
Inclinometer An inclinometer or clinometer is an instrument used for measuring angles of slope, elevation, or depression of an object with respect to gravity's direction. It is also known as a ''tilt indicator'', ''tilt sensor'', ''tilt meter'', ''slope ...
* Mural instrument * Protractor * Quadrant * Reflecting instruments ** Octant ** Reflecting circles **
Sextant A sextant is a doubly reflecting navigation instrument that measures the angular distance between two visible objects. The primary use of a sextant is to measure the angle between an astronomical object and the horizon for the purposes of cel ...
*
Theodolite A theodolite () is a precision optical instrument for measuring angles between designated visible points in the horizontal and vertical planes. The traditional use has been for land surveying, but it is also used extensively for building and ...


Orientation in three-dimensional space

See also the section about navigation below.


Level

*
Level (instrument) A level is an optical instrument used to establish or verify points in the same horizontal plane in a process known as levelling, and is used in conjunction with a levelling staff to establish the relative height levels of objects or marks. It is ...
* Laser line level *
Spirit level A spirit level, bubble level, or simply a level, is an instrument designed to indicate whether a surface is horizontal (level) or vertical ( plumb). Different types of spirit levels may be used by carpenters, stonemasons, bricklayers, oth ...


Direction

* Gyroscope


Mechanics

This includes basic quantities found in classical- and
continuum mechanics Continuum mechanics is a branch of mechanics that deals with the mechanical behavior of materials modeled as a continuous mass rather than as discrete particles. The French mathematician Augustin-Louis Cauchy was the first to formulate such ...
; but strives to exclude temperature-related questions or quantities.


Mass- or volume flow measurement

*
Gas meter A gas meter is a specialized flow meter, used to measure the volume of fuel gases such as natural gas and liquefied petroleum gas. Gas meters are used at residential, commercial, and industrial buildings that consume fuel gas supplied by a g ...
* Mass flow meter *
Metering pump A metering pump moves a precise volume of liquid in a specified time period providing an accurate volumetric flow rate. Delivery of fluids in precise adjustable flow rates is sometimes called metering. The term "metering pump" is based on the ap ...
*
Water meter Water metering is the practice of measuring water use. Water meters measure the volume of water used by residential and commercial building units that are supplied with water by a public water supply system. They are also used to determine flo ...


Speed or velocity (flux of length)

*
Airspeed indicator The airspeed indicator (ASI) or airspeed gauge is a flight instrument indicating the airspeed of an aircraft in kilometers per hour (km/h), knots (kn), miles per hour (MPH) and/or meters per second (m/s). The recommendation by ICAO is to use ...
*
LIDAR speed gun Lidar (, also LIDAR, or LiDAR; sometimes LADAR) is a method for determining ranges (variable distance) by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the receiver. It can also be ...
* Radar speed gun, a
Doppler radar A Doppler radar is a specialized radar that uses the Doppler effect to produce velocity data about objects at a distance. It does this by bouncing a microwave signal off a desired target and analyzing how the object's motion has altered the fr ...
device, using the
Doppler effect The Doppler effect or Doppler shift (or simply Doppler, when in context) is the change in frequency of a wave in relation to an observer who is moving relative to the wave source. It is named after the Austrian physicist Christian Doppler, ...
for indirect measurement of velocity. *
Speedometer A speedometer or speed meter is a gauge that measures and displays the instantaneous speed of a vehicle. Now universally fitted to motor vehicles, they started to be available as options in the early 20th century, and as standard equipment ...
*
Tachometer A tachometer (revolution-counter, tach, rev-counter, RPM gauge) is an instrument measuring the rotation speed of a shaft or disk, as in a motor or other machine. The device usually displays the revolutions per minute (RPM) on a calibrated analo ...
(speed of rotation) *
Tachymeter Tachymeter may refer to: *Tachymeter (survey) Tacheometry (; from Greek for "quick measure") is a system of rapid surveying, by which the horizontal and vertical positions of points on the earth's surface relative to one another are determine ...
* Variometer (rate of climb or descent) * Velocimetry (measurement of fluid velocity) For the ranges of speed-values see:
Orders of magnitude (speed) To help compare different orders of magnitude, the following list describes various speed levels between approximately 2.2  m/s and 3.0 m/s (the speed of light). Values in bold are exact. List of orders of magnitude for speed See also * ...


Acceleration

*
Accelerometer An accelerometer is a tool that measures proper acceleration. Proper acceleration is the acceleration (the rate of change of velocity) of a body in its own instantaneous rest frame; this is different from coordinate acceleration, which is acce ...


Mass

* Balance * Check weigher measures precise weight of items in a conveyor line, rejecting underweight or overweight objects. *
Inertial balance An inertial balance is a device that allows the measurement of inertial mass (as opposed to gravitational mass for a regular balance) that can be operated in the microgravity environment space where weight is negligible (e.g. in the Internationa ...
*
Katharometer The thermal conductivity detector (TCD), also known as a katharometer, is a bulk property detector and a chemical specific detector commonly used in gas chromatography. This detector senses changes in the thermal conductivity of the column eluent ...
*
Mass spectrometer Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a '' mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is u ...
s measure the
mass-to-charge ratio The mass-to-charge ratio (''m''/''Q'') is a physical quantity relating the ''mass'' (quantity of matter) and the ''electric charge'' of a given particle, expressed in units of kilograms per coulomb (kg/C). It is most widely used in the electro ...
, not the mass, of ionised particles. *
Weighing scale A scale or balance is a device used to measure weight or mass. These are also known as mass scales, weight scales, mass balances, and weight balances. The traditional scale consists of two plates or bowls suspended at equal distances from ...
For the ranges of mass-values see:
Orders of magnitude (mass) To help compare different Order of magnitude, orders of magnitude, the following lists describe various mass levels between 10−59 kilogram, kg and 1052 kg. The least massive thing listed here is a graviton, and the most massive thing ...


Linear momentum

* Ballistic pendulum


Force (flux of linear momentum)

*
Force gauge A force gauge (also called a force meter) is a measuring instrument used to measure forces. Applications exist in research and development, laboratory, quality, production and field environment. There are two kinds of force gauges today: mechanica ...
* Spring scale *
Strain gauge A strain gauge (also spelled strain gage) is a device used to measure strain on an object. Invented by Edward E. Simmons and Arthur C. Ruge in 1938, the most common type of strain gauge consists of an insulating flexible backing which supports ...
* Torsion balance * Tribometer


Pressure (flux density of linear momentum)

*
Anemometer In meteorology, an anemometer () is a device that measures wind speed and direction. It is a common instrument used in weather stations. The earliest known description of an anemometer was by Italian architect and author Leon Battista Alberti ...
(measures
wind speed In meteorology, wind speed, or wind flow speed, is a fundamental atmospheric quantity caused by air moving from high to low pressure, usually due to changes in temperature. Wind speed is now commonly measured with an anemometer. Wind spee ...
) *
Barometer A barometer is a scientific instrument that is used to measure air pressure in a certain environment. Pressure tendency can forecast short term changes in the weather. Many measurements of air pressure are used within surface weather analysis ...
used to measure the
atmospheric pressure Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1013.25 millibar ...
. *
Manometer Pressure measurement is the measurement of an applied force by a fluid (liquid or gas) on a surface. Pressure is typically measured in units of force per unit of surface area. Many techniques have been developed for the measurement of pressu ...
(see
Pressure measurement Pressure measurement is the measurement of an applied force by a fluid (liquid or gas) on a surface. Pressure is typically measured in units of force per unit of surface area. Many techniques have been developed for the measurement of press ...
and
Pressure sensor A pressure sensor is a device for pressure measurement of gases or liquids. Pressure is an expression of the force required to stop a fluid from expanding, and is usually stated in terms of force per unit area. A pressure sensor usually a ...
) *
Pitot tube A pitot ( ) tube (pitot probe) measures fluid flow velocity. It was invented by a French engineer, Henri Pitot, in the early 18th century, and was modified to its modern form in the mid-19th century by a French scientist, Henry Darcy. It ...
(measures
airspeed In aviation, airspeed is the speed of an aircraft relative to the air. Among the common conventions for qualifying airspeed are: * Indicated airspeed ("IAS"), what is read on an airspeed gauge connected to a Pitot-static system; * Calib ...
) * Tire-pressure gauge in industry and mobility For the ranges of pressure-values see: Orders of magnitude (pressure)


Angular velocity or rotations per time unit

*
Stroboscope A stroboscope, also known as a strobe, is an instrument used to make a cyclically moving object appear to be slow-moving, or stationary. It consists of either a rotating disk with slots or holes or a lamp such as a flashtube which produces b ...
*
Tachometer A tachometer (revolution-counter, tach, rev-counter, RPM gauge) is an instrument measuring the rotation speed of a shaft or disk, as in a motor or other machine. The device usually displays the revolutions per minute (RPM) on a calibrated analo ...
For the value-ranges of angular velocity see:
Orders of magnitude (angular velocity) Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or with the notation min−1) is a unit of rotational speed or rotational frequency for rotating machines. Standards ISO 80000-3:2019 defines a unit of rotation as the dimensio ...
For the ranges of frequency see: Orders of magnitude (frequency)


Torque

*
Dynamometer A dynamometer or "dyno" for short, is a device for simultaneously measuring the torque and rotational speed ( RPM) of an engine, motor or other rotating prime mover so that its instantaneous power may be calculated, and usually displayed by t ...
* Prony brake *
Torque wrench A torque wrench is a tool used to apply a specific torque to a fastener such as a nut, bolt, or lag screw. It is usually in the form of a socket wrench with an indicating scale, or an internal mechanism which will indicate (as by 'clicking' ...


Energy carried by mechanical quantities, mechanical work

* Ballistic pendulum, indirectly by calculation and or gauging


Electricity, electronics, and electrical engineering

Considerations related to
electric charge Electric charge is the physical property of matter that causes charged matter to experience a force when placed in an electromagnetic field. Electric charge can be ''positive'' or ''negative'' (commonly carried by protons and electrons respecti ...
dominate
electricity Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as describ ...
and
electronics The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons using electronic devices. Electronics uses active devices to control electron flow by amplification ...
. Electrical charges interact via a field. That field is called electric field.If the charge doesn't move. If the charge moves, thus realizing an electric current, especially in an electrically neutral conductor, that field is called
magnetic Magnetism is the class of physical attributes that are mediated by a magnetic field, which refers to the capacity to induce attractive and repulsive phenomena in other entities. Electric currents and the magnetic moments of elementary particles ...
. Electricity can be given a quality — a
potential Potential generally refers to a currently unrealized ability. The term is used in a wide variety of fields, from physics to the social sciences to indicate things that are in a state where they are able to change in ways ranging from the simple r ...
. And electricity has a substance-like property, the electric charge. Energy (or power) in elementary electrodynamics is calculated by multiplying the potential by the amount of charge (or current) found at that potential: potential times charge (or current). (See
Classical electromagnetism Classical electromagnetism or classical electrodynamics is a branch of theoretical physics that studies the interactions between electric charges and currents using an extension of the classical Newtonian model; It is, therefore, a classical fi ...
and
Covariant formulation of classical electromagnetism The covariant formulation of classical electromagnetism refers to ways of writing the laws of classical electromagnetism (in particular, Maxwell's equations and the Lorentz force) in a form that is manifestly invariant under Lorentz transformati ...
)


Electric charge

*
Electrometer An electrometer is an electrical instrument for measuring electric charge or electrical potential difference. There are many different types, ranging from historical handmade mechanical instruments to high-precision electronic devices. Modern e ...
is often used to reconfirm the phenomenon of contact electricity leading to triboelectric sequences. * Torsion balance used by
Coulomb The coulomb (symbol: C) is the unit of electric charge in the International System of Units (SI). In the present version of the SI it is equal to the electric charge delivered by a 1 ampere constant current in 1 second and to elementary ch ...
to establish a relation between charges and force, see above. For the ranges of charge values see: Orders of magnitude (charge)


Electric current (current of charge)

*
Ammeter An ammeter (abbreviation of ''Ampere meter'') is an instrument used to measure the current in a circuit. Electric currents are measured in amperes (A), hence the name. For direct measurement, the ammeter is connected in series with the circuit ...
* Clamp meter *
d'Arsonval galvanometer A galvanometer is an electromechanical measuring instrument for electric current. Early galvanometers were uncalibrated, but improved versions, called ammeters, were calibrated and could measure the flow of current more precisely. A galvanom ...
*
Galvanometer A galvanometer is an electromechanical measuring instrument for electric current. Early galvanometers were uncalibrated, but improved versions, called ammeters, were calibrated and could measure the flow of current more precisely. A galvano ...


Voltage Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge t ...
(
electric potential The electric potential (also called the ''electric field potential'', potential drop, the electrostatic potential) is defined as the amount of work energy needed to move a unit of electric charge from a reference point to the specific point in ...
difference)

* Oscilloscope allows quantifying time-dependent voltages *
Voltmeter A voltmeter is an instrument used for measuring electric potential difference between two points in an electric circuit. It is connected in parallel. It usually has a high resistance so that it takes negligible current from the circuit. An ...


Electric resistance The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is , measuring the ease with which an electric current passes. Electrical resistance shares some conceptual parallel ...
,
electrical conductance The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is , measuring the ease with which an electric current passes. Electrical resistance shares some conceptual parallel ...
, and
electrical conductivity Electrical resistivity (also called specific electrical resistance or volume resistivity) is a fundamental property of a material that measures how strongly it resists electric current. A low resistivity indicates a material that readily allows ...

*
Ohmmeter An analog ohmmeter An ohmmeter is an electrical instrument that measures electrical resistance (the opposition offered by a circuit or component to the flow of electric current). Multimeters also function as ohmmeters when in resistance-measu ...
* Time-domain reflectometer characterizes and locates faults in metallic cables by
runtime measurement Time of flight (ToF) is the measurement of the time taken by an object, particle or wave (be it acoustic, electromagnetic, etc.) to travel a distance through a medium. This information can then be used to measure velocity or path length, or as a w ...
s of electric signals. *
Wheatstone bridge A Wheatstone bridge is an electrical circuit used to measure an unknown electrical resistance by balancing two legs of a bridge circuit, one leg of which includes the unknown component. The primary benefit of the circuit is its ability to provide ...


Electric capacitance

*
Capacitance meter A capacitance meter is a piece of electronic test equipment used to measure capacitance, mainly of discrete capacitors. Depending on the sophistication of the meter, it may display the capacitance only, or it may also measure a number of other p ...


Electric inductance

*
Inductance meter An LCR meter is a type of electronic test equipment used to measure the inductance (L), capacitance (C), and resistance (R) of an electronic component. In the simpler versions of this instrument the impedance was measured internally and conve ...


Energy carried by electricity or electric energy

*
Electricity meter North American domestic analog electricity meter. Electricity meter with transparent plastic case (Israel) North American domestic electronic electricity meter An electricity meter, electric meter, electrical meter, energy meter, or kilowa ...


Power carried by electricity ( current of energy)

*
Wattmeter The wattmeter is an instrument for measuring the electric active power (or the average of the rate of flow of electrical energy) in watts of any given circuit. Electromagnetic wattmeters are used for measurement of utility frequency and audio ...


Electric field (negative

gradient In vector calculus, the gradient of a scalar-valued differentiable function of several variables is the vector field (or vector-valued function) \nabla f whose value at a point p is the "direction and rate of fastest increase". If the gr ...
of electric potential, voltage per length)

* Field mill


Magnetic field A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and t ...

See also the relevant section in the article about the
magnetic field A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and t ...
. *
Compass A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself with ...
*
Hall effect sensor A Hall effect sensor (or simply Hall sensor) is a type of sensor which detects the presence and magnitude of a magnetic field using the Hall effect. The output voltage of a Hall sensor is directly proportional to the strength of the field. ...
*
Magnetometer A magnetometer is a device that measures magnetic field or magnetic dipole moment. Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location. A compass is one such device, o ...
* Proton magnetometer *
SQUID True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting ...
For the ranges of magnetic field see: Orders of magnitude (magnetic field)


Combination instruments

*
Multimeter A multimeter is a measuring instrument that can measure multiple electrical properties. A typical multimeter can measure voltage, resistance, and current, in which case it is also known as a volt-ohm-milliammeter (VOM), as the unit is equipped w ...
, combines the functions of ammeter, voltmeter, and ohmmeter as a minimum. *
LCR meter An LCR meter is a type of electronic test equipment used to measure the inductance (L), capacitance (C), and resistance (R) of an electronic component. In the simpler versions of this instrument the impedance was measured internally and conver ...
, combines the functions of ohmmeter, capacitance meter, and inductance meter. Also called ''component bridge'' due to the
bridge circuit A bridge circuit is a topology of electrical circuitry in which two circuit branches (usually in parallel with each other) are "bridged" by a third branch connected between the first two branches at some intermediate point along them. The bridge ...
method of measurement.


Thermodynamics Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed by the four laws o ...

Temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied on ...
-related considerations dominate thermodynamics. There are two distinct thermal properties: A thermal potential — the temperature. For example: A glowing coal has a different thermal quality than a non-glowing one. And a substance-like property, — the
entropy Entropy is a scientific concept, as well as a measurable physical property, that is most commonly associated with a state of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodyna ...
; for example: One glowing coal won't heat a pot of water, but a hundred will. Energy in thermodynamics is calculated by multiplying the thermal potential by the amount of entropy found at that potential: temperature times entropy. Entropy can be created by friction but not annihilated.


Amount of substance In chemistry, the amount of substance ''n'' in a given sample of matter is defined as the quantity or number of discrete atomic-scale particles in it divided by the Avogadro constant ''N''A. The particles or entities may be molecules, atoms, io ...
(or
mole number The mole, symbol mol, is the unit of amount of substance in the International System of Units (SI). The quantity amount of substance is a measure of how many elementary entities of a given substance are in an object or sample. The mole is define ...
)

:A physical quantity introduced in chemistry; usually determined indirectly. If mass and substance type of the sample are known, then atomic- or
molecular mass The molecular mass (''m'') is the mass of a given molecule: it is measured in daltons (Da or u). Different molecules of the same compound may have different molecular masses because they contain different isotopes of an element. The related quant ...
es (taken from a
periodic table The periodic table, also known as the periodic table of the (chemical) elements, is a rows and columns arrangement of the chemical elements. It is widely used in chemistry, physics, and other sciences, and is generally seen as an icon of ...
, masses measured by
mass spectrometry Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a '' mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is u ...
) give direct access to the value of the amount of substance. (See also
Molar mass In chemistry, the molar mass of a chemical compound is defined as the mass of a sample of that compound divided by the amount of substance which is the number of moles in that sample, measured in moles. The molar mass is a bulk, not molecula ...
.) If specific molar values are given, then the amount of substance of a given sample may be determined by measuring volume, mass, or concentration. See also the subsection below about the measurement of the boiling point. *
Gas collecting tube The characterization gas collecting tube describes an oblong gas-tight container with one valve at either end. Usually such a container has a gauged volume, has a cylindrical shape and is made of glass. Gas collecting tubes are used for science- ...
gases


Temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied on ...

* Electromagnetic spectroscopy *
Galileo thermometer A Galileo thermometer (or Galilean thermometer) is a thermometer made of a sealed glass cylinder containing a clear liquid and several glass vessels of varying density. The individual floats rise or fall in proportion to their respective densit ...
*
Gas thermometer A gas thermometer is a thermometer that measures temperature by the variation in volume or pressure of a gas. Volume Thermometer This thermometer functions by Charles's Law. Charles's Law states that when the temperature of a gas increases, so d ...
principle: relation between temperature and volume or pressure of a gas (
gas laws The gas laws were developed at the end of the 18th century, when scientists began to realize that relationships between pressure, volume and temperature of a sample of gas could be obtained which would hold to approximation for all gases. Boyl ...
). **
Constant pressure gas thermometer Constant or The Constant may refer to: Mathematics * Constant (mathematics), a non-varying value * Mathematical constant, a special number that arises naturally in mathematics, such as or Other concepts * Control variable or scientific const ...
** Constant volume gas thermometer *
Liquid crystal thermometer A liquid crystal thermometer, temperature strip or plastic strip thermometer is a type of thermometer that contains heat-sensitive (thermochromic) liquid crystals in a plastic strip that change colour to indicate different temperatures. Liquid cry ...
* Liquid thermometer principle: relation between temperature and volume of a liquid (
coefficient of thermal expansion Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions. Temperature is a monotonic function of the average molecular kinetic ...
). **
Alcohol thermometer The alcohol thermometer or spirit thermometer is an alternative to the mercury-in-glass thermometer and has similar functions. Unlike the mercury-in-glass thermometer, the contents of an alcohol thermometer are less toxic and will evaporate qu ...
**
Mercury-in-glass thermometer The mercury-in-glass or mercury thermometer was invented by physicist Daniel Gabriel Fahrenheit in Amsterdam (1714). It consists of a bulb containing mercury attached to a glass tube of narrow diameter; the volume of mercury in the tube is much ...
*
Pyranometer A pyranometer is a type of actinometer used for measuring solar irradiance on a planar surface and it is designed to measure the solar radiation flux density (W/m2) from the hemisphere above within a wavelength range 0.3 μm to 3 μm. The name pyran ...
principle: solar radiation flux density relates to surface temperature (
Stefan–Boltzmann law The Stefan–Boltzmann law describes the power radiated from a black body in terms of its temperature. Specifically, the Stefan–Boltzmann law states that the total energy radiated per unit surface area of a black body across all wavelengths ...
) *
Pyrometer A pyrometer is a type of remote-sensing thermometer used to measure the temperature of distant objects. Various forms of pyrometers have historically existed. In the modern usage, it is a device that from a distance determines the temperature of ...
s principle: temperature dependence of spectral intensity of light (
Planck's law In physics, Planck's law describes the spectral density of electromagnetic radiation emitted by a black body in thermal equilibrium at a given temperature , when there is no net flow of matter or energy between the body and its environment. A ...
), i.e. the color of the light relates to the temperature of its source, range: from about −50 °C to +4000 °C, note: measurement of
thermal radiation Thermal radiation is electromagnetic radiation generated by the thermal motion of particles in matter. Thermal radiation is generated when heat from the movement of charges in the material (electrons and protons in common forms of matter) is ...
(instead of
thermal conduction Conduction is the process by which heat is transferred from the hotter end to the colder end of an object. The ability of the object to conduct heat is known as its ''thermal conductivity'', and is denoted . Heat spontaneously flows along a te ...
, or thermal convection) means: no physical contact becomes necessary in temperature measurement ( pyrometry). Also note: thermal space resolution (images) found in
thermography Infrared thermography (IRT), thermal video and/or thermal imaging, is a process where a thermal camera captures and creates an image of an object by using infrared radiation emitted from the object in a process, which are examples of infrared ...
. *
Resistance thermometer Resistance thermometers, also called resistance temperature detectors (RTDs), are sensors used to measure temperature. Many RTD elements consist of a length of fine wire wrapped around a heat-resistant ceramic or glass core but other constructi ...
principle: relation between temperature and electrical resistance of metals (platinum) (
electrical resistance The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is , measuring the ease with which an electric current passes. Electrical resistance shares some conceptual parallel ...
), range: 10 to 1,000 kelvins, application in physics and industry *
Solid thermometer Solid is one of the four fundamental states of matter (the others being liquid, gas, and plasma). The molecules in a solid are closely packed together and contain the least amount of kinetic energy. A solid is characterized by structural ri ...
principle: relation between temperature and length of a solid (
coefficient of thermal expansion Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions. Temperature is a monotonic function of the average molecular kinetic ...
). **
Bimetallic strip A bimetallic strip is used to convert a temperature change into mechanical displacement. The strip consists of two strips of different metals which expand at different rates as they are heated. The different expansions force the flat strip to be ...
*
Thermistor A thermistor is a type of resistor whose resistance is strongly dependent on temperature, more so than in standard resistors. The word thermistor is a portmanteau of ''thermal'' and ''resistor''. Thermistors are divided based on their conduction ...
s principle: relation between temperature and electrical resistance of ceramics or polymers, range: from about 0.01 to 2,000 kelvins (−273.14 to 1,700 °C) *
Thermocouple A thermocouple, also known as a "thermoelectrical thermometer", is an electrical device consisting of two dissimilar electrical conductors forming an electrical junction. A thermocouple produces a temperature-dependent voltage as a result of th ...
s principle: relation between temperature and voltage of metal junctions ( Seebeck effect), range: from about −200 °C to +1350 °C *
Thermometer A thermometer is a device that measures temperature or a temperature gradient (the degree of hotness or coldness of an object). A thermometer has two important elements: (1) a temperature sensor (e.g. the bulb of a mercury-in-glass thermomete ...
*
Thermopile A thermopile is an electronic device that converts thermal energy into electrical energy. It is composed of several thermocouples connected usually in series or, less commonly, in parallel. Such a device works on the principle of the thermoele ...
is a set of connected
thermocouple A thermocouple, also known as a "thermoelectrical thermometer", is an electrical device consisting of two dissimilar electrical conductors forming an electrical junction. A thermocouple produces a temperature-dependent voltage as a result of th ...
s * Triple point cell used for calibrating thermometers.


Imaging technology

*
Thermographic camera Infrared thermography (IRT), thermal video and/or thermal imaging, is a process where a thermal camera captures and creates an image of an object by using infrared radiation emitted from the object in a process, which are examples of infrared ...
uses a microbolometer for detection of heat radiation. See also
Temperature measurement Temperature measurement (also known as thermometry) describes the process of measuring a current local temperature for immediate or later evaluation. Datasets consisting of repeated standardized measurements can be used to assess temperature tren ...
and :Thermometers. More technically related may be seen
thermal analysis Thermal analysis is a branch of materials science where the properties of materials are studied as they change with temperature. Several methods are commonly used – these are distinguished from one another by the property which is measured: * ...
methods in materials science. For the ranges of temperature-values see: Orders of magnitude (temperature)


Energy In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of hea ...
carried by
entropy Entropy is a scientific concept, as well as a measurable physical property, that is most commonly associated with a state of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodyna ...
or
thermal energy The term "thermal energy" is used loosely in various contexts in physics and engineering. It can refer to several different well-defined physical concepts. These include the internal energy or enthalpy of a body of matter and radiation; heat, ...

This includes
thermal mass In building design, thermal mass is a property of the mass of a building that enables it to store heat and provide inertia against temperature fluctuations. It is sometimes known as the thermal flywheel effect. The thermal mass of heavy structura ...
or temperature coefficient of energy, reaction energy,
heat flow Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy (heat) between physical systems. Heat transfer is classified into various mechanisms, such as thermal conduction, ...
, ... Calorimeters are called passive if gauged to measure emerging energy carried by entropy, for example from chemical reactions. Calorimeters are called active or heated if they heat the sample, or reformulated: if they are gauged to fill the sample with a defined amount of entropy. *Actinometer heating power of radiation. *Constant-temperature calorimeter, phase change calorimeter for example an ice calorimeter or any other calorimeter observing a phase change or using a gauged phase change for heat measurement. *Constant-volume calorimeter, also called bomb calorimeter *Constant-pressure calorimeter, enthalpy-meter, or coffee cup calorimeter *Differential scanning calorimetry, Differential Scanning Calorimeter *Reaction calorimeter :See also Calorimeter or Calorimetry


Entropy

Entropy is accessible indirectly by measurement of energy and temperature.


Entropy transfer

Phase change calorimeter's energy value divided by absolute temperature give the entropy exchanged. Phase changes produce no entropy and therefore offer themselves as an entropy measurement concept. Thus entropy values occur indirectly by processing energy measurements at defined temperatures, without producing entropy. *Constant-temperature calorimeter, phase change calorimeter *Heat flux sensor uses thermopiles (which are connected
thermocouple A thermocouple, also known as a "thermoelectrical thermometer", is an electrical device consisting of two dissimilar electrical conductors forming an electrical junction. A thermocouple produces a temperature-dependent voltage as a result of th ...
s) to determine current density or
flux Flux describes any effect that appears to pass or travel (whether it actually moves or not) through a surface or substance. Flux is a concept in applied mathematics and vector calculus which has many applications to physics. For transport ...
of entropy.


Entropy content

The given sample is cooled down to (almost) absolute zero (for example by submerging the sample in liquid helium). At absolute zero temperature any sample is assumed to contain no entropy (see Third law of thermodynamics for further information). Then the following two active calorimeter types can be used to fill the sample with entropy until the desired temperature has been reached: (see also Thermodynamic databases for pure substances) *Constant-pressure calorimeter, enthalpy-meter, active *Constant-temperature calorimeter, phase change calorimeter, active


Entropy production

Processes transferring energy from a non-thermal carrier to heat as a carrier do produce entropy (Example: mechanical/electrical friction, established by Benjamin Thompson, Count Rumford). Either the produced entropy or heat are measured (calorimetry) or the transferred energy of the non-thermal carrier may be measured. *calorimeter *(any device for measuring the work which will or would eventually be converted to heat and the ambient temperature) Entropy lowering its temperature—without losing energy—produces entropy (Example: Heat conduction in an isolated rod; "thermal friction"). *calorimeter


Temperature coefficient of energy or "heat capacity"

Concerning a given sample, a proportionality factor relating temperature change and energy carried by heat. If the sample is a gas, then this coefficient depends significantly on being measured at constant volume or at constant pressure. (The terminiology preference in the heading indicates that the classical use of heat bars it from having substance-like properties.) *Constant-volume calorimeter, bomb calorimeter *Constant-pressure calorimeter, enthalpy-meter


Specific temperature coefficient of energy or "specific heat capacity"

The temperature coefficient of energy divided by a substance-like quantity (amount of substance, mass, volume) describing the sample. Usually calculated from measurements by a division or could be measured directly using a unit amount of that sample. For the ranges of specific heat capacities see: Orders of magnitude (specific heat capacity)


Coefficient of thermal expansion

*Dilatometer *
Strain gauge A strain gauge (also spelled strain gage) is a device used to measure strain on an object. Invented by Edward E. Simmons and Arthur C. Ruge in 1938, the most common type of strain gauge consists of an insulating flexible backing which supports ...


Melting point, Melting temperature (of a solid)

*Differential scanning calorimetry, Differential Scanning Calorimeter gives melting point and enthalpy of fusion. *Kofler bench *Thiele tube


Boiling point, Boiling temperature (of a liquid)

*Ebullioscope a device for measuring the boiling point of a liquid. This device is also part of a method that uses the effect of boiling point elevation for calculating the
molecular mass The molecular mass (''m'') is the mass of a given molecule: it is measured in daltons (Da or u). Different molecules of the same compound may have different molecular masses because they contain different isotopes of an element. The related quant ...
of a solvent. See also Thermal analysis, Heat.


More on

continuum mechanics Continuum mechanics is a branch of mechanics that deals with the mechanical behavior of materials modeled as a continuous mass rather than as discrete particles. The French mathematician Augustin-Louis Cauchy was the first to formulate such ...

This includes mostly instruments which measure macroscopic properties of matter: In the fields of solid-state physics; in condensed matter physics which considers solids, liquids, and in-betweens exhibiting for example viscoelasticity, viscoelastic behavior. Furthermore, fluid mechanics, where liquids, gases, plasma (physics), plasmas, and in-betweens like supercritical fluids are studied.


Density

This refers to particle density (particle count), particle density of fluids and compact(ed) solids like crystals, in contrast to bulk density of grainy or porous solids. *Aerometer liquids *Dasymeter gases *
Gas collecting tube The characterization gas collecting tube describes an oblong gas-tight container with one valve at either end. Usually such a container has a gauged volume, has a cylindrical shape and is made of glass. Gas collecting tubes are used for science- ...
gases *Hydrometer liquids *Pycnometer liquids *Resonant frequency and damping analyser (RFDA) solids For the ranges of density-values see: Orders of magnitude (density)


Hardness of a solid

*Durometer


Shape and surface of a solid

*Holographic interferometry, Holographic interferometer *Laser produced speckle pattern analysed. *Resonant frequency and damping analyser (RFDA) * Tribometer


Deformation (engineering), Deformation of condensed matter

*
Strain gauge A strain gauge (also spelled strain gage) is a device used to measure strain on an object. Invented by Edward E. Simmons and Arthur C. Ruge in 1938, the most common type of strain gauge consists of an insulating flexible backing which supports ...
all below


Elasticity (physics), Elasticity of a solid (elastic moduli)

*Resonant frequency and damping analyser (RFDA), using the impulse excitation technique: A small mechanical impulse causes the sample to vibrate. The vibration depends on elastic properties, density, geometry, and inner structures (lattice or fissures).


Plasticity (physics), Plasticity of a solid

*Cam plastometer *Plastometer


Tensile strength, ductility, or malleability of a solid

*Universal testing machine


Granularity of a solid or of a suspension (chemistry), suspension

*Grindometer


Viscosity of a fluid

*Rheometer *Viscometer


Optical activity

*Polarimetry, Polarimeter


Surface tension of liquids

*Tensiometer (surface tension), Tensiometer


Imaging technology

*Tomography, Tomograph, device and method for non-destructive analysis of multiple measurements done on a geometric object, for producing 2- or 3-dimensional images, representing the inner structure of that geometric object. *Wind tunnel This section and the following sections include instruments from the wide field of :Materials science, materials science.


More on electric properties of condensed matter, gas


Permittivity, relative static permittivity, (dielectric constant), or electric susceptibility

*Capacitor Such measurements also allow to access values of dipole#Molecular dipoles, molecular dipoles.


Magnetic susceptibility or magnetization

*Gouy balance For other methods see the section in the article about magnetic susceptibility#Experimental methods to determine susceptibility, magnetic susceptibility. See also :Electric and magnetic fields in matter


Substance potential or chemical potential or molar Gibbs energy

Phase (matter), Phase conversions like changes of state of matter, aggregate state, chemical reactions or nuclear reactions transmuting substances, from reactants into product (chemistry), products, or diffusion through membrane (selective barrier), membranes have an overall energy balance. Especially at constant pressure and constant temperature, molar energy balances define the notion of a substance potential or chemical potential or molar Gibbs energy, which gives the energetic information about whether the process is possible or not - in a closed system. Energy balances that include entropy consist of two parts: A balance that accounts for the changed entropy content of the substances, and another one that accounts for the energy freed or taken by that reaction itself, the Gibbs energy change. The sum of reaction energy and energy associated to the change of entropy content is also called enthalpy. Often the whole enthalpy is carried by entropy and thus measurable calorimetrically. For standard conditions in chemical reactions either molar entropy content and molar Gibbs energy with respect to some chosen zero point are tabulated. Or molar entropy content and molar enthalpy with respect to some chosen zero are tabulated. (See Standard enthalpy change of formation and Standard molar entropy) The substance potential of a redox chemical reaction, reaction is usually determined electrochemistry, electrochemically current-free using reversible cells. *Redox electrode Other values may be determined indirectly by calorimetry. Also by analyzing phase-diagrams.


Sub-microstructure, microstructural properties of condensed matter, gas

*Infrared spectroscopy *Neutron detector *Radio frequency spectrometers for nuclear magnetic resonance and electron paramagnetic resonance *Raman spectroscopy


Crystal structure

*An X-ray tube, a sample scattering the X-rays and a photographic plate to detect them. This constellation forms the scattering instrument used by X-ray crystallography for investigating crystal structures of samples. Amorphous solids lack a distinct pattern and are identifiable thereby.


Imaging technology, microscope

*Electron microscope **Scanning electron microscope **Transmission electron microscope *Optical microscope uses reflectiveness or refractiveness of light to produce an image. *Scanning acoustic microscope *Scanning probe microscopy, Scanning probe microscope **Atomic force microscope (AFM) **Scanning tunneling microscope (STM) *Focus variation *X-ray microscope (See also Spectroscopy and List of materials analysis methods.)


Rays ("waves" and "subatomic particle, particles")


Sound, compression waves in matter

Microphones in general, sometimes their sensitivity is increased by the reflection- and concentration principle realized in acoustic mirrors. *Laser microphone *Seismometer


Sound pressure

*Microphone or hydrophone properly gauged *Shock tube *Sound level meter


Light and radiation without a rest mass, non-ionizing radiation, non-ionizing

*Antenna (radio) *Bolometer measuring the energy of incident electromagnetic radiation. *Camera *EMF meter *Interferometer used in the wide field of interferometry *Microwave power meter *Optical power meter *Photographic plate *Photomultiplier *Phototube *Radio telescope *Spectrometer *Terahertz time-domain spectroscopy, T-ray detectors (for lux meter, see the section about human senses and human body) See also :Optical devices


Photon polarization

*Polarizer


Pressure (current density of linear momentum)

*Nichols radiometer


Radiant flux

The measure of the total power of light emitted. *Integrating sphere for measuring the total radiant flux of a light source


Radiation with a rest mass, particle radiation


Cathode rays

*Crookes tube *Cathode-ray tube, a phosphor-coated anode


Atom polarization and electron polarization

*Stern–Gerlach experiment


Ionizing radiation

Ionizing radiation includes rays of "particles" as well as rays of "waves". Especially X-rays and gamma rays transfer enough energy in non-thermal, (single-) collision processes to separate electron(s) from an atom.


Particle and ray

flux Flux describes any effect that appears to pass or travel (whether it actually moves or not) through a surface or substance. Flux is a concept in applied mathematics and vector calculus which has many applications to physics. For transport ...

*Bubble chamber *Cloud chamber *Dosimeter, a technical device realizes different working principles. *Geiger counter *Ionisation chamber *Microchannel plate detector *Photographic plate *Photostimulable phosphor plate *Proportional counter *Scintillation counter, Lucas cell *Semiconductor detector


Identification and content

This could include chemical substances, rays of any kind, elementary particles, and quasiparticles. Many measurement devices outside this section may be used or at least become part of an identification process. For identification and content concerning chemical substances, see also Analytical chemistry, List of chemical analysis methods, and List of materials analysis methods.


Chemical substance, Substance content in mixtures, substance identification

*Carbon dioxide sensor *Chromatography, chromatographic device, gas chromatograph separates mixtures of substances. Different velocities of the substance types accomplish the separation. *Colorimeter (chemistry), Colorimeter absorbance, and thus concentration *Gas detector *Gas chromatography-mass spectrometry, Gas detector in combination with mass spectrometer, *Mass spectrometry, mass spectrometer identifies the chemical composition of a sample on the basis of the mass-to-charge ratio of charged particles. *Nephelometer or turbidimeter *Oxygen sensor (= lambda sond) *Refractometer, indirectly by determining the refractive index of a substance. *Smoke detector *Ultracentrifuge, separates mixtures of substances. In a force field of a centrifuge, substances of different densities separate.


pH: Concentration of protons in a solution

*pH meter *Saturated calomel electrode


Humidity

*Hygrometer the density of water in air *Lysimeter the balance of water in soil


Sense, Human senses and human body


Visual perception, Sight


Brightness: photometry (optics), photometry

Photometry is the measurement of light in terms of its perceived brightness to the human eye. Photometric quantities derive from analogous radiometry, radiometric quantities by weighting the contribution of each wavelength by a luminosity function that models the eye's spectral sensitivity. For the ranges of possible values, see the orders of magnitude in: Orders of magnitude (illuminance), illuminance, Orders of magnitude (luminance), luminance, and Orders of magnitude (luminous flux), luminous flux. *Photometers of various kinds: **Lux meter for measuring illuminance, i.e. incident luminous flux per unit area **Luminance meter for measuring luminance, i.e. luminous flux per unit area and unit solid angle **Light meter, an instrument used to set exposure (photography), photographic exposures. It can be either a lux meter (incident-light meter) or a luminance meter (reflected-light meter), and is calibrated in photographic units. *Integrating sphere for collecting the total luminous flux of a light source, which can then be measured by a photometer *Densitometer for measuring the degree to which a photographic material reflects or transmits light


Color: colorimetry

*Tristimulus colorimeter for quantifying colors and calibrating an imaging workflow


Radar brightness: radiometry

Synthetic-aperture radar, Synthetic Aperture Radar (SAR) instruments measure radar brightness, radar cross-section, Radar Cross Section (RCS), which is a function of the reflection (physics), reflectivity and moisture of imaged objects at wavelengths which are too long to be perceived by the human eye. Black pixels mean no reflectivity (e.g. water surfaces), white pixels mean high reflectivity (e.g. urban areas). Colored pixels can be obtained by combining three gray-scaled images which usually interpret the polarization (waves), polarization of electromagnetic waves. The combination R-G-B = HH-HV-VV combines radar images of waves sent and received horizontally (HH), sent horizontally and received vertically (HV) and sent and received vertically (VV). The calibration of such instruments is done by imaging objects (calibration targets) whose radar brightness is known.


Hearing


Loudness in phon

*Headphone, loudspeaker, sound pressure gauge, for measuring an equal-loudness contour of a human ear. *Sound level meter calibrated to an equal-loudness contour of the human auditory system behind the human ear.


Smell

*Olfactometer, see also Olfaction#Quantifying olfaction in industry, Olfaction.


Temperature (sense and body)


Normal human body temperature, Body temperature or core temperature

*Medical thermometer, see also infrared thermometer


Circulatory system (mainly heart and blood vessels for distributing substances fast)

Blood-related parameters are listed in a blood test. *Electrocardiogram, Electrocardiograph records the electrical activity of the heart *Glucose meter for obtaining the status of blood sugar. *Sphygmomanometer, a blood pressure meter used to determine blood pressure in medicine. See also :Blood tests


Respiratory system (lung and airways controlling the breathing process)

*Spirometer


Concentration or partial pressure of carbon dioxide in the respiratory gases

*Capnography, Capnograph


Nervous system (nerves transmitting and processing information electrically)

*Electroencephalography, Electroencephalograph records the electrical activity of the brain


Musculoskeletal system (muscles and bones for movement)


Power (physics), power, mechanical work, work of muscles

*Exercise machine, Ergometer


Metabolism, metabolic system

*Body fat meter


Medical imaging

*Computed tomography *Magnetic resonance imaging *Medical ultrasonography *Radiology *Tomography, Tomograph, device and method for non-destructive analysis of multiple measurements done on a geometric object, for producing 2- or 3-dimensional images, representing the inner structure of that geometric object. See also: :Physiological instruments and :Medical testing equipment.


Meteorology

See also :Meteorological instrumentation and equipment.


Navigation and surveying

See also :Navigational equipment and :Navigation. See also Surveying instruments.


Astronomy

*Radio astronomy, Radio antenna *Telescope See also Astronomical instruments and :Astronomical observatories.


Military

Some instruments, such as telescopes and sea navigation instruments, have had military applications for many centuries. However, the role of instruments in military affairs rose exponentially with the development of technology via applied science, which began in the mid-19th century and has continued through the present day. Military instruments as a class draw on most of the categories of instrument described throughout this article, such as #Navigation, navigation, #Astronomy, astronomy, optics, and imaging, and the kinetics of moving objects. Common abstract themes that unite military instruments are seeing into the distance, seeing in the dark, knowing an object's geographic location, and knowing and controlling a moving object's path and destination. Special features of these instruments may include ease of use, speed, reliability (statistics), reliability, and accuracy.


Uncategorized, specialized, or generalized application

*Actograph measures and records animal activity within an experimental chamber. *Densitometer measures light transmission through processed photographic film or transparent material or light reflection from a reflective material. *Force platform measures ground reaction force. *Gauge (engineering) A highly precise measurement instrument, also usable to calibration, calibrate other instruments of the same kind. Often found in conjunction with defining or applying standard (technical), technical standards. *Gradiometer any device that measures spatial variations of a
physical quantity A physical quantity is a physical property of a material or system that can be quantified by measurement. A physical quantity can be expressed as a ''value'', which is the algebraic multiplication of a ' Numerical value ' and a ' Unit '. For examp ...
. For example, as done in gravity gradiometry. *Parking meter measures time a vehicle is parked at a particular spot, usually with a fee. *Postage meter measures postage used from a prepaid account. *S meter measures the signal strength processed by a communications receiver. *Sensor, hypernym for devices that measure with little interaction, typically used in technical applications. *Spectroscope is an important tool used by physicists. *SWR meter check the quality of the match between the antenna (radio), antenna and the transmission line. *Universal measuring machine measures geometric locations for inspecting tolerance (engineering), tolerances.


Alphabetical listing


See also

*:Instrument-making corporations *Data logger measuring devices *History of measurement *History of weights and measures *Instrumentation *List of measuring devices *List of physical quantities *List of sensors *Metrology *Pocket comparator *Sensor or detector *Timeline of temperature and pressure measurement technology *Wikipedia:WikiProject Physics/Worklist of central experiments


Notes

The alternate spelling "metre, -metre" is never used when referring to a measuring device.


References


External links

* {{Authority control Measuring instruments, Metrology