Measuring instrument - wikipedia Measuring instrument Captain Nemo and Professor Aronnax contemplating measuring instruments in Twenty Thousand Leagues Under the Sea A Love Meter and Strength tester machine at a Framingham, Massachusetts rest stop. A measuring instrument is a device for measuring a physical quantity. In the physical sciences, quality assurance, and engineering, measurement is the activity of obtaining and comparing physical quantities 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 methods 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. Scientists, engineers and other humans use a vast range of instruments to perform their measurements. These instruments may range from simple objects such as rulers and stopwatches to electron microscopes and particle accelerators. Virtual instrumentation is widely used in the development of modern measuring instruments. Contents 1 Time 2 Energy 2.1 Electricity meter 2.2 Gas meter 3 Power ( flux of energy ) 4 Action 5 Mechanics 5.1 Length ( distance ) 5.2 Area 5.3 Volume 5.4 Mass - or volume flow measurement 5.5 Speed ( flux of length ) 5.6 Acceleration 5.7 Mass 5.8 Linear momentum 5.9 Force ( flux of linear momentum ) 5.10 Pressure ( flux density of linear momentum ) 5.11 Angle 5.12 Angular velocity or rotations per time unit 5.13 Torque 5.14 Orientation in three - dimensional space 5.14. 1 Level 5.14. 2 Direction 5.15 Energy carried by mechanical quantities, mechanical work 6 Electricity, electronics and electrical engineering 6.1 Electric charge 6.2 Electric current ( current of charge ) 6.3 Voltage ( electric potential difference ) 6.4 Electric resistance, electrical conductance ( and electrical conductivity ) 6.5 Electric capacitance 6.6 Electric inductance 6.7 Energy carried by electricity or electric energy 6.8 Power carried by electricity ( current of energy ) 6.9 Electric field ( negative gradient of electric potential, voltage per length ) 6.10 Magnetic field 6.11 Combination instruments 7 Thermodynamics 7.1 Amount of substance ( or mole number ) 7.2 Temperature 7.2. 1 Imaging technology 7.3 Energy carried by entropy or thermal energy 7.4 Entropy 7.4. 1 Entropy transfer 7.4. 2 Entropy content 7.4. 3 Entropy production 7.5 temperature coefficient of energy or `` heat capacity '' 7.6 specific temperature coefficient of energy or `` specific heat '' 7.7 Coefficient of thermal expansion 7.8 Melting temperature ( of a solid ) 7.9 Boiling temperature ( of a liquid ) 8 More on continuum mechanics 8.1 Density 8.2 Hardness of a solid 8.3 Shape and surface of a solid 8.4 Deformation of condensed matter 8.4. 1 Elasticity of a solid ( elastic moduli ) 8.4. 2 Plasticity of a solid 8.4. 3 Tensile strength, ductility or malleability of a solid 8.5 Granularity of a solid or of a suspension 8.6 Viscosity of a fluid 8.7 Optical activity 8.8 Surface tension of liquids 8.9 Imaging technology 9 More on electric properties of condensed matter, gas 9.1 Permittivity, relative static permittivity, ( dielectric constant ) or electric susceptibility 9.2 Magnetic susceptibility or magnetization 9.3 Substance potential or chemical potential or molar Gibbs energy 10 Sub-microstructural properties of condensed matter, gas 10.1 Crystal structure 10.2 Imaging technology, Microscope 11 Rays ( `` waves '' and `` particles '' ) 11.1 Sound, compression waves in matter 11.1. 1 Sound pressure 11.2 Light and radiation without a rest mass, non-ionizing 11.2. 1 Photon polarization 11.2. 2 Pressure ( current density of linear momentum ) 11.2. 3 Radiant flux 11.3 Radiation with a rest mass, particle radiation 11.3. 1 Cathode ray 11.3. 2 Atom polarization and electron polarization 11.4 Ionizing radiation 11.4. 1 Particle and ray flux 12 Identification and content 12.1 Substance content in mixtures, substance identification 12.1. 1 pH : Concentration of protons in a solution 12.1. 2 Humidity 13 Human senses and human body 13.1 Sight 13.1. 1 Brightness : photometry 13.1. 2 Color : colorimetry 13.2 Hearing 13.2. 1 Loudness in phon 13.3 Smell 13.4 Temperature ( sense and body ) 13.4. 1 Body temperature or core temperature 13.5 Circulatory system ( mainly heart and blood vessels for distributing substances fast ) 13.6 Respiratory system ( lung and airways controlling the breathing process ) 13.6. 1 Concentration or partial pressure of carbon dioxide in the respiratory gases 13.7 Nervous system ( nerves transmitting and processing information electrically ) 13.8 Musculoskeletal system ( muscles and bones for movement ) 13.8. 1 power, work of muscles 13.9 metabolic system 13.10 Medical imaging 14 Meteorology 15 Navigation and surveying 16 Astronomy 17 Military 18 Uncategorized, specialized, or generalized application 18.1 Fictional devices 19 See also 20 Notes 21 References Time Watch, a time measurement device Main article : Time In the past, a common time measuring instrument was the sundial. Today, the usual measuring instruments for time are clocks and watches. For highly accurate measurement of time an atomic clock is used. Stop watches are also used to measure time in some sports. Energy Main article : Energy Energy is measured by an energy meter. Examples of energy meters include : Electricity meter An electricity meter measures energy directly in kilowatt hours. Gas meter A gas meter 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 of the gas. Power ( flux of energy ) Main article : Power ( physics ) A physical system that exchanges energy may be described by the amount of energy exchanged per time - interval, also called power or flux of energy. ( see any measurement device for power below ) For the ranges of power - values see : Orders of magnitude ( power ). Action Main article : Action ( physics ) Action describes energy summed up over the time a process lasts ( time integral over energy ). Its dimension is the same as that of an angular momentum. A phototube provides a voltage measurement which permits the calculation of the quantized action ( Planck constant ) of light. Also see photoelectric effect. Mechanics This includes basic quantities found in classical - and continuum mechanics ; but strives to exclude temperature - related questions or quantities. Length ( distance ) Length, distance, or range meter For the ranges of length - values see : Orders of magnitude ( length ) Area Planimeter For the ranges of area - values see : Orders of magnitude ( area ) Volume A measuring cup, a common instrument used to measure volume. Buoyant weight ( solids ) Overflow trough ( solids ) Measuring cup ( grained solids, liquids ) Flow measurement devices ( liquids ) Graduated cylinder ( liquids ) Pipette ( liquids ) Eudiometer, pneumatic trough ( gases ) 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 ) Mass - or volume flow measurement Gas meter Mass flow meter Metering pump Water meter Speed ( flux of length ) Airspeed indicator Radar gun, a Doppler radar device, using the Doppler effect for indirect measurement of velocity. LIDAR speed gun Speedometer Tachometer ( speed of rotation ) Tachymeter Variometer For the ranges of speed - values see : Orders of magnitude ( speed ) Acceleration Accelerometer Mass A pair of scales : An instrument for measuring mass in a force field by balancing forces. Balance Automatic checkweighing machines Katharometer Weighing scales Inertial balance Mass spectrometers measure the mass - to - charge ratio, not the mass. For the ranges of mass - values see : Orders of magnitude ( mass ) Linear momentum Ballistic pendulum Force ( flux of linear momentum ) Force gauge Spring scale Strain gauge Torsion balance Tribometer Measuring absolute pressure in an accelerated reference frame : The principle of a mercury ( Hg ) barometer in the gravitational field of the earth. Pressure ( flux density of linear momentum ) Anemometer ( used to determine wind speed ) Barometer used to measure the atmospheric pressure. Manometer see pressure measurement Pitot tube ( used to determine speed ) Tire - pressure gauge in industry and mobility For the ranges of pressure - values see : Orders of magnitude ( pressure ) See also : Timeline of temperature and pressure measurement technology Angle Circumferentor Cross staff Goniometer Graphometer Protractor Quadrant Reflecting instruments Octant Reflecting circles Sextant Theodolite Angular velocity or rotations per time unit Stroboscope Tachometer For the value - ranges of angular velocity see : Orders of magnitude ( angular velocity ) For the ranges of frequency see : Orders of magnitude ( frequency ) Torque Dynamometer de Prony brake Torque wrench Orientation in three - dimensional space See also the section about navigation below. Level Dumpy level Laser line level Spirit level Direction Gyroscope Energy carried by mechanical quantities, mechanical work Ballistic pendulum, indirectly by calculation and or gauging Electricity, electronics and electrical engineering See also : Electrical measurements Considerations related to electric charge dominate electricity and electronics. Electrical charges interact via a field. That field is called electric if the charge does n't move. If the charge moves, thus realizing an electric current, especially in an electrically neutral conductor, that field is called magnetic. Electricity can be given a quality -- a potential. 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 and its Covariant formulation of classical electromagnetism ) An instrument for detecting net charges, the electroscope. Electric charge Electrometer is often used to reconfirm the phenomenon of contact electricity leading to triboelectric sequences. Torsion balance used by Coulomb 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 ) This section needs more links to other articles to help integrate it into the encyclopedia. Please help improve this article by adding links that are relevant to the context within the existing text. ( November 2013 ) Ammeter Clamp meter Galvanometer D'Arsonval galvanometer Voltage ( electric potential difference ) Oscilloscope allows to quantify time depended voltages Voltmeter Electric resistance, electrical conductance ( and electrical conductivity ) Ohmmeter Time - domain reflectometer characterizes and locates faults in metallic cables by runtime measurements of electric signals. Wheatstone bridge Electric capacitance Capacitance meter Electric inductance Inductance meter Energy carried by electricity or electric energy Electric energy meter Electricity meter Power carried by electricity ( current of energy ) Wattmeter Electric field ( negative gradient of electric potential, voltage per length ) Field mill Magnetic field See also the relevant section in the article about the magnetic field. Compass Hall effect sensor Magnetometer Proton magnetometer SQUID For the ranges of magnetic field see : Orders of magnitude ( magnetic field ) Combination instruments Multimeter, combines the functions of ammeter, voltmeter and ohmmeter as a minimum. LCR meter, combines the functions of ohmmeter, capacitance meter and inductance meter. Also called component bridge due to the bridge circuit method of measurement. Thermodynamics Temperature - 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 ; for example : One glowing coal wo n't heat a pot of water, but a hundred will. Energy in thermodynamics is calculated by multipying 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 ( or mole number ) A physical quantity introduced in chemistry ; usually determined indirectly. If mass and substance type of the sample are known, then atomic - or molecular masses ( taken from a periodic table, masses measured by mass spectrometry ) give direct access to the value of the amount of substance. See also the article about molar masses. 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 gases Temperature Electromagnetic spectroscopy Galileo thermometer Gas thermometer principle : relation between temperature and volume or pressure of a gas ( Gas laws ). constant pressure gas thermometer constant volume gas thermometer Liquid crystal thermometer liquid thermometer principle : relation between temperature and volume of a liquid ( Coefficient of thermal expansion ). Alcohol thermometer Mercury - in - glass thermometer Pyranometer principle : solar radiation flux density relates to surface temperature ( Stefan -- Boltzmann law ) Pyrometers principle : temperature dependence of spectral intensity of light ( Planck 's law ), 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 ( instead of thermal conduction, or thermal convection ) means : no physical contact becomes necessary in temperature measurement ( pyrometry ). Also note : thermal space resolution ( images ) found in Thermography. Resistance thermometer principle : relation between temperature and electrical resistance of metals ( platinum ) ( Electrical resistance ), range : 10 to 1,000 kelvins, application in physics and industry solid thermometer principle : relation between temperature and length of a solid ( Coefficient of thermal expansion ). Bi-metallic strip Thermistors 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 ) Thermocouples principle : relation between temperature and voltage of metal junctions ( Seebeck effect ), range : from about − 200 ° C to + 1350 ° C Thermometer Thermopile is a set of connected thermocouples Triple Point cell used for calibrating thermometers. Imaging technology Thermographic camera uses a microbolometer for detection of heat - radiation. See also Temperature measurement and Category : Thermometers. More technically related may be seen thermal analysis methods in materials science. For the ranges of temperature - values see : Orders of magnitude ( temperature ) Energy carried by entropy or thermal energy An active calorimeter lacking a temperature measurement device. This includes thermal capacitance or temperature coefficient of energy, reaction energy, heat flow... 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 measures the 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 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 thermocouples to determine current density or flux 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 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 '' 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 Melting temperature ( of a solid ) Thiele tube Kofler bench Differential Scanning Calorimeter gives melting point and enthalpy of fusion. 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 of a solvent. See also thermal analysis, Heat. More on continuum mechanics 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 viscoelastic behavior. Furthermore, fluid mechanics, where liquids, gases, plasmas and in - betweens like supercritical fluids are studied. Density This refers to 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 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 interferometer Laser produced speckle pattern analysed. Resonant frequency and Damping Analyser ( RFDA ) Tribometer Deformation of condensed matter Strain gauge all below 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 of a solid Cam plastometer Plastometer Measurement results ( a ) brittle ( b ) ductile with breaking point ( c ) ductile without breaking point. Tensile strength, ductility or malleability of a solid Universal Testing Machine Granularity of a solid or of a suspension Grindometer Viscosity of a fluid Rheometer Viscometer Optical activity Polarimeter Surface tension of liquids Tensiometer Imaging technology 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 Category : Materials science, materials science. More on electric properties of condensed matter, gas The electrochemical cell : A device for measuring substance potentials. Permittivity, relative static permittivity, ( dielectric constant ) or electric susceptibility Capacitor Such measurements also allow to access values of molecular dipoles. Magnetic susceptibility or magnetization Gouy balance For other methods see the section in the article about magnetic susceptibility. See also the Category : Electric and magnetic fields in matter Substance potential or chemical potential or molar Gibbs energy Phase conversions like changes of aggregate state, chemical reactions or nuclear reactions transmuting substances, from reactants to products, or diffusion through 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 reaction is usually determined electrochemically current - free using reversible cells. Redox electrode Other values may be determined indirectly by calorimetry. Also by analyzing phase - diagrams. See also the article on electrochemistry. Sub-microstructural properties of condensed matter, gas Infrared spectroscopy Neutron detector Radio frequency spectrometers for Nuclear magnetic resonance and for 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 identifyable thereby. Imaging technology, microscope Electron microscope Transmission electron microscope Optical microscope uses reflectiveness or refractiveness of light to produce an image. Scanning acoustic microscope Scanning probe microscope Atomic force microscope ( AFM ) Scanning electron microscope Scanning tunneling microscope ( STM ) Focus variation X-ray microscope See also the article on spectroscopy and the list of materials analysis methods. Rays ( `` waves '' and `` 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 A device for unmixing sun - light : the prism. The electromagnetic spectrum Light and radiation without a rest mass, non-ionizing Antenna ( radio ) Bolometer measuring the energy of incident electromagnetic radiation. Camera EMF meter Interferometer used in the wide field of Interferometry Optical power meter Microwave power meter Photographic plate Photomultiplier Phototube Radio telescope Spectrometer T - ray detectors ( for lux meter see the section about human senses and human body ) See also Category : 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 A Cathode ray tube. Radiation with a rest mass, particle radiation Cathode ray Crookes tube Cathode ray tube, a phosphor coated anode Atom polarization and electron polarization Stern -- Gerlach experiment Another visualization of the electromagnetic spectrum. 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. A cloud chamber detecting alpha - rays. Particle and ray flux Bubble chamber Cloud chamber Dosimeter, a technical device realizes different working principles. Geiger counter Microchannel plate detector Photographic plate Photostimulable phosphors Scintillation counter, Lucas cell Semiconductor detector proportional counter ionisation chamber Identification and content This could include chemical substances, rays of any kind, elementary particles, 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 especially its List of chemical analysis methods and the List of materials analysis methods. Substance content in mixtures, substance identification Carbon dioxide sensor chromatographic device, gas chromatograph separates mixtures of substances. Different velocites of the substance types accomplish the separation. Colorimeter ( measures absorbance, and thus concentration ) gas detector Gas detector in combination with mass spectrometer, 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 measures the density of water in air Lysimeter measures the balance of water in soil Human senses and human body This section may require cleanup to meet Wikipedia 's quality standards. The specific problem is : non-standard section titles Please help improve this section if you can. ( February 2013 ) Vitruvian Man by Leonardo da Vinci, Gallerie dell'Accademia, Venice ( 1485 - 90 ) Sight Brightness : photometry Photometry is the measurement of light in terms of its perceived brightness to the human eye. Photometric quantities derive from analogous 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 : illuminance, luminance, and 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 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 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 the article about olfaction. Temperature ( sense and body ) 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. 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 Category : Blood tests Respiratory system ( lung and airways controlling the breathing process ) A spirometer, inhaling into pipe a fills volume b, the rest balances forces. Spirometer Concentration or partial pressure of carbon dioxide in the respiratory gases Capnograph Nervous system ( nerves transmitting and processing information electrically ) Electroencephalograph records the electrical activity of the brain Musculoskeletal system ( muscles and bones for movement ) power, work of muscles Ergometer metabolic system Body fat meter Medical imaging An echocardiogram processed into a three dimensional representation. Computed tomography Magnetic resonance imaging Medical ultrasonography Radiology 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 : Category : Physiological instruments and Category : Medical testing equipment. Meteorology See also Category : Meteorological instrumentation and equipment. Navigation and Surveying See also Category : Navigational equipment and Category : Navigation. See also Surveying instruments. Astronomy Radio antenna Telescope See also Astronomical instruments and Category : 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, 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 and accuracy. Uncategorized, specialized, or generalized application Aktograph measures and records animal activity within an experimental chamber. Checkweigher measures precise weight of items in a conveyor line, rejecting under or overweight objects. 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 calibrate other instruments of the same kind. Often found in conjunction with defining or applying technical standards. Gradiometer any device that measures spatial variations of a physical quantity. 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 and the transmission line. Time - domain reflectometer locates faults in metallic cables. Universal measuring machine measures geometric locations for inspecting tolerances. Fictional devices Tricorder, a multipurpose scanning device, originating from the science - fictional Star Trek series. Sonic Screwdriver, a multifunctional device used occasionally for scanning, originating from the science - fictional Doctor Who series. See also Astronomy portal Analytical chemistry portal Electronics portal Energy portal Time portal Category : Instrument - making corporations Data loggers measuring devices Detectors History of weights and measures History of measurement Instrumentation List of measuring devices for a more comprehensive, alphabetical list of devices and the corresponding list of physical quantities. List of sensors Metrology Timeline of temperature and pressure measurement technology Wikipedia : WikiProject Physics / Worklist of central experiments Pocket comparator Notes Note that the alternate spelling `` - metre '' is never used when referring to a measuring device. References Wikimedia Commons has media related to Measuring instruments. 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Question: name three tools that scientists could use to measure liquids
Answer: Measuring cup