First developed in the 18th century, units of energy measurement are used both in everyday life and the international energy trade. They have been standardized among different countries. Producers, distributors and consumers have to be able to measure the energy they sell, transport or use according to its properties. They use different units of measurement appropriate to each type of energy.
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Physical Quantities and Their UnitsVIDEO ON THE TOPIC: Revu 2017: Measurement Tool Enhancements
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. 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. 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. An electricity meter measures energy directly in kilowatt hours. 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. 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.
For the ranges of power-values see: Orders of magnitude power. 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. This includes basic quantities found in classical - and continuum mechanics ; but strives to exclude temperature-related questions or quantities. For the ranges of length-values see: Orders of magnitude length.
For the ranges of area-values see: Orders of magnitude area. For the ranges of volume-values see: Orders of magnitude volume. For the ranges of speed-values see: Orders of magnitude speed. For the ranges of mass-values see: Orders of magnitude mass. For the ranges of pressure-values see: Orders of magnitude pressure. For the value-ranges of angular velocity see: Orders of magnitude angular velocity. For the ranges of frequency see: Orders of magnitude frequency.
Considerations related to electric charge dominate electricity and electronics. 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. 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. For the ranges of charge values see: Orders of magnitude charge. See also the relevant section in the article about the magnetic field. For the ranges of magnetic field see: Orders of magnitude magnetic field.
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 won'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.
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. 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.
Entropy is accessible indirectly by measurement of energy and temperature. 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.
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.
Either the produced entropy or heat are measured calorimetry or the transferred energy of the non-thermal carrier may be measured. Entropy lowering its temperature—without losing energy—produces entropy Example: Heat conduction in an isolated rod; "thermal friction". 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. 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.
See also thermal analysis , Heat. 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. This refers to particle density of fluids and compact ed solids like crystals, in contrast to bulk density of grainy or porous solids.
For the ranges of density-values see: Orders of magnitude density. This section and the following sections include instruments from the wide field of Category:Materials science , materials science. Such measurements also allow to access values of molecular dipoles. For other methods see the section in the article about magnetic susceptibility.
See also the Category:Electric and magnetic fields in matter. 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. See also the article on electrochemistry. See also the article on spectroscopy and the list of materials analysis methods. Microphones in general, sometimes their sensitivity is increased by the reflection- and concentration principle realized in acoustic mirrors.
See also Category:Optical devices. 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. 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. 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. Blood-related parameters are listed in a blood test. See also: Category:Physiological instruments and Category:Medical testing equipment. See also Category:Meteorological instrumentation and equipment.
A millimeter or millimetre is a unit of length used to make standardized measurements as part of the metric system. One millimeter is one one-thousandth of a meter. There are a couple ways to measure millimeters. The first and simplest method is to use a metric ruler, which is conveniently labeled with millimeter markings.
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Electricity is measured in units of power called Watts, named to honor James Watt, the inventor of the steam engine. A Watt is the unit of electrical power equal to one ampere under the pressure of one volt. One Watt is a small amount of power. Some devices require only a few Watts to operate, and other devices require larger amounts.
For most SketchUp 3D models, the unit of measurement is critical to the success of your final project. For example, buildings are typically modeled in feet or meters; woodworking projects in inches or centimeters. This article introduces the ways you can control units of measurement in your sketchUp model and points you to other relevant articles for more detailed information. When you start a new 3D modeling project in SketchUp, you select a template. The template determines the unit of measurement for your model as a whole.SEE VIDEO BY TOPIC: Measure Tool in Blender 2.8
Measurement is the assignment of a number to a characteristic of an object or event, which can be compared with other objects or events. In the natural sciences and engineering , measurements do not apply to nominal properties of objects or events, which is consistent with the guidelines of the International vocabulary of metrology published by the International Bureau of Weights and Measures. Measurement is a cornerstone of trade , science , technology , and quantitative research in many disciplines. Historically, many measurement systems existed for the varied fields of human existence to facilitate comparisons in these fields. Often these were achieved by local agreements between trading partners or collaborators. Since the 18th century, developments progressed towards unifying, widely accepted standards that resulted in the modern International System of Units SI. This system reduces all physical measurements to a mathematical combination of seven base units. The science of measurement is pursued in the field of metrology. The measurement of a property may be categorized by the following criteria: type , magnitude , unit , and uncertainty. The system defines seven fundamental units : kilogram , metre , candela , second , ampere , kelvin , and mole.
This book, written for the benefit of engineering students and practicing engineers alike, is the culmination of the author's four decades of experience related to the subject of electrical measurements, comprising nearly 30 years of experimental research and more than 15 years of teaching at several engineering institutions. Enhancing the chapters are interspersed explanatory comments and, where necessary, footnotes to help better understanding of the chapter contents. Also, each chapter begins with a "recall" to link the subject matter with the related science or phenomenon and fundamental background.
Measure Map lets you quickly and easily measure multiple distances, perimeters and areas with laser sharp precision! Use it for small areas or large, then share your findings via any sharing app you have on your device. Calculate surface areas, buildings, plots, floors, forest areas or dimensions for fencing, sports tours, trips or anything you need for field work without having to go to the spot to take measurements. Only one finger to calculate with astonishing accuracy all these measurements over satellite images. It does all that, fast and effortlessly. Just one "Magic" button for all the operations to easily place points without losing it's professional accuracy. We are proud to announce our latest webapp version, Measure Map Online , it has all the capabilities that our famous Android, iOS and Windows 10 Pro versions have and much more. It can be used on any platform with Google Chrome Also designed for mobile. Take pictures of important things in your project and include them in your measurements and pdf reports. Soon in Android and Windows. We are proud to announce our latest software yet, Measure Map Pro for Windows 10 Desktop , it has all the capabilities that our famous Android and iOS versions have.
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Choosing Appropriate Units of Measure
A unit of measurement is a quantity used as a standard to expressed a physical quantity. The following are the basic quantities being measured and the respective units used:. Length — describes how long something is. Distance, height, thickness, and depth also use the same units. It is also used in measuring the height of a person. It is commonly used to express short distances, and height of all objects like trees and buildings. For short distances, the metric unit meter m and the English unit yard yd are commonly used. For long distances, the metric unit kilometer km and the English unit mile mi are commonly used. It is commonly used to express the mass of small objects like orange, egg, and tomato. It is commonly used in determining the age of an infant or a baby animal.
David P. Gene D. Theory and Practice of Radiation Thermometry.
Refrigeration and Air Conditioning Technology. Refrigeration and Air Conditioning Technology, 6th Edition, a time-honored best seller, has been updated and revised to provide superior hands-on information needed to successfully maintain and troubleshoot today's complex heating, air conditioning, and refrigeration systems.
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.
In the physical world around us, we come across the quantities such as time, distance, mass, area, volume, and so on. In a mathematics course, we are more interested in the units of measurements, which are used to describe the magnitude of each of these quantities.