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. Artifact-free definitions fix measurements at an exact value related to a physical constant or other invariable phenomena in nature, in contrast to standard artifacts which are subject to deterioration or destruction. Instead, the measurement unit can only ever change through increased accuracy in determining the value of the constant it is tied to.
The first proposal to tie an SI base unit to an experimental standard independent of fiat was by Charles Sanders Peirce — ,  who proposed to define the metre in terms of the wavelength of a spectral line. With the exception of a few fundamental quantum constants, units of measurement are derived from historical agreements. Nothing inherent in nature dictates that an inch has to be a certain length, nor that a mile is a better measure of distance than a kilometre. Over the course of human history, however, first for convenience and then for necessity, standards of measurement evolved so that communities would have certain common benchmarks.
Laws regulating measurement were originally developed to prevent fraud in commerce. Units of measurement are generally defined on a scientific basis, overseen by governmental or independent agencies, and established in international treaties, pre-eminent of which is the General Conference on Weights and Measures CGPM , established in by the Metre Convention , overseeing the International System of Units SI and having custody of the International Prototype Kilogram.
The metre, for example, was redefined in by the CGPM in terms of light speed, while in the international yard was defined by the governments of the United States, United Kingdom, Australia and South Africa as being exactly 0. Before SI units were widely adopted around the world, the British systems of English units and later imperial units were used in Britain, the Commonwealth and the United States. The system came to be known as U. These various systems of measurement have at times been called foot-pound-second systems after the Imperial units for length, weight and time even though the tons, hundredweights, gallons, and nautical miles, for example, are different for the U.
Many Imperial units remain in use in Britain, which has officially switched to the SI system—with a few exceptions such as road signs, which are still in miles. Draught beer and cider must be sold by the imperial pint, and milk in returnable bottles can be sold by the imperial pint. Many people measure their height in feet and inches and their weight in stone and pounds, to give just a few examples. Imperial units are used in many other places, for example, in many Commonwealth countries that are considered metricated, land area is measured in acres and floor space in square feet, particularly for commercial transactions rather than government statistics.
PROCESS MEASUREMENT & CONTROL APPRECIATION
Similarly, gasoline is sold by the gallon in many countries that are considered metricated. The metric system is a decimal system of measurement based on its units for length, the metre and for mass, the kilogram. It exists in several variations, with different choices of base units , though these do not affect its day-to-day use.
Since the s, the International System of Units SI is the internationally recognised metric system. Metric units of mass, length, and electricity are widely used around the world for both everyday and scientific purposes. It is the world's most widely used system of units , both in everyday commerce and in science.
The SI was developed in from the metre-kilogram- second MKS system, rather than the centimetre-gram-second CGS system, which, in turn, had many variants. During its development the SI also introduced several newly named units that were previously not a part of the metric system. The original SI units for the seven basic physical quantities were: . The mole was subsequently added to this list and the degree Kelvin renamed the kelvin.
There are two types of SI units, base units and derived units. Base units are the simple measurements for time, length, mass, temperature, amount of substance, electric current and light intensity. Derived units are constructed from the base units, for example, the watt , i. The SI allows easy multiplication when switching among units having the same base but different prefixes.
To convert from metres to centimetres it is only necessary to multiply the number of metres by , since there are centimetres in a metre. Inversely, to switch from centimetres to metres one multiplies the number of centimetres by 0. A ruler or rule is a tool used in, for example, geometry , technical drawing , engineering, and carpentry, to measure lengths or distances or to draw straight lines.
Strictly speaking, the ruler is the instrument used to rule straight lines and the calibrated instrument used for determining length is called a measure , however common usage calls both instruments rulers and the special name straightedge is used for an unmarked rule.
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The use of the word measure , in the sense of a measuring instrument, only survives in the phrase tape measure , an instrument that can be used to measure but cannot be used to draw straight lines. As can be seen in the photographs on this page, a two-metre carpenter's rule can be folded down to a length of only 20 centimetres, to easily fit in a pocket, and a five-metre-long tape measure easily retracts to fit within a small housing.
The Australian building trades adopted the metric system in and the units used for measurement of length are metres m and millimetres mm. Centimetres cm are avoided as they cause confusion when reading plans. American surveyors use a decimal-based system of measurement devised by Edmund Gunter in A link is abbreviated "lk," and links "lks" in old deeds and land surveys done for the government.
Time is an abstract measurement of elemental changes over a non spatial continuum. It is an apparently irreversible series of occurrences within this non spatial continuum. It is also used to denote an interval between two relative points on this continuum. Mass refers to the intrinsic property of all material objects to resist changes in their momentum.
Weight , on the other hand, refers to the downward force produced when a mass is in a gravitational field. In free fall , no net gravitational forces objects lack weight but retain their mass. The Imperial units of mass include the ounce , pound , and ton. The metric units gram and kilogram are units of mass. One device for measuring weight or mass is called a weighing scale or, often, simply a scale.
A spring scale measures force but not mass, a balance compares weight, both require a gravitational field to operate. Some of the most accurate instruments for measuring weight or mass are based on load cells with a digital read-out, but require a gravitational field to function and would not work in free fall. The measures used in economics are physical measures, nominal price value measures and real price measures. These measures differ from one another by the variables they measure and by the variables excluded from measurements.
In the field of survey research, measures are taken from individual attitudes, values, and behavior using questionnaires as a measurement instrument. As all other measurements, measurement in survey research is also vulnerable to measurement error , i. In order to get accurate results, when measurement errors appear, the results need to be corrected for measurement errors. Since accurate measurement is essential in many fields, and since all measurements are necessarily approximations, a great deal of effort must be taken to make measurements as accurate as possible.
Using physics, it can be shown that, in the gravitational field of the Earth, it should take any object about 0. However, the following are just some of the sources of error that arise:. Additionally, other sources of experimental error include:. Scientific experiments must be carried out with great care to eliminate as much error as possible, and to keep error estimates realistic.
In the classical definition, which is standard throughout the physical sciences, measurement is the determination or estimation of ratios of quantities. The classical concept of quantity can be traced back to John Wallis and Isaac Newton , and was foreshadowed in Euclid's Elements. In the representational theory, measurement is defined as "the correlation of numbers with entities that are not numbers". The flowchart below is a good example of using process mapping to understand and improve a process.
In this chart, the process is making pasta. Even though this is a very simplified process map example, many parts of business use similar diagrams to understand processes and improve process efficiency, such as operations, finance, supply chain, sales, marketing and accounting. Process mapping spotlights waste, streamlines work processes and builds understanding. Process mapping allows you to visually communicate the important details of a process rather than writing extensive directions. Process maps help you to understand the important characteristics of a process, allowing you to produce helpful data to use in problem solving.
Process maps let you strategically ask important questions that help you improve any process. Diagramming is quick and easy with Lucidchart. Start a free trial today to start creating and collaborating. Process mapping is about communicating your process to others.
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You can build stronger understanding with process maps. The most common process map types include:. In business, a process is a group of interrelated tasks that happen as a result of an event. These tasks produce a desired result for the customer.
Process mapping can be used in many areas of business: business process improvement, business process redesign, reengineering, training, quality improvement, simulation, information technology, work measurement, documentation, process analysis, operational process design, process integration, acquisitions, mergers and selling business operations. Business process mapping can also be helpful for complying with manufacturing and service industry regulations, such as the common ISO International Organization for Standardization or ISO Process mapping has become streamlined because of software that provides a better understanding of processes.
Process maps can be created in common programs like Microsoft Word, PowerPoint or Excel, but there are other programs more customized to creating a process map. Process mapping is about communicating your process to others so that you achieve your management objectives. Knowing how to map a process will help you build stronger communication and understanding in your organization.
Each element in a process map is represented by a specific flowchart symbol.
When important information is presented visually, it increases understanding and collaboration for any project. Mapping out a process is an excellent way to improve efficiency in any organization. With drag-and-drop design and online collaboration, Lucidchart makes it easy to process map anytime, from anywhere. What is Process Mapping What are your process map needs?
I'm new to process maps and want to learn more. I want to make my own process map in Lucidchart. I want to make a process map from a Lucidchart template.
Contents Purpose of process mapping Understanding processes Benefits of process mapping Types of process mapping Process mapping symbols Business process mapping How to create a process map. Make a process map or. Purpose of process mapping The purpose of process mapping is for organizations and businesses to improve efficiency. Understanding processes One of the purposes of process mapping is to gain better understanding of a process. Benefits of process mapping Process mapping spotlights waste, streamlines work processes and builds understanding.
Flowcharts and process maps are used to: Increase understanding of a process Analyze how a process could be improved Show others how a process is done Improve communication between individuals engaged in the same process Provide process documentation Plan projects Process maps can save time and simplify projects because they: Create and speed up the project design Provide effective visual communication of ideas, information and data Help with problem solving and decision making Identify problems and possible solutions Can be built quickly and economically Show processes broken down into steps and use symbols that are easy to follow Show detailed connections and sequences Show an entire process from the beginning to the end Process maps help you to understand the important characteristics of a process, allowing you to produce helpful data to use in problem solving.
Types of process mapping Process mapping is about communicating your process to others. Basic symbols are used in a process map to describe key process elements.