View source for Size

{{Short description|Magnitude or dimension of a thing}}
{{other uses|Size (disambiguation)}}
{{redirect|Physical dimension|the dimension of a physical quantity|Dimension (physics)}}
{{redirect|Resizing|resizing of digital images|image scaling}}
[[File:Megalodon-Carcharodon-Scale-Chart-SVG.svg|thumb|right|A diagram comparing the size of an average human diver to the size of the modern [[great white shark]], [[whale shark]], and the prehistoric [[megalodon]]. The illustration also contains a linear measurement in meters in the middle.]]
[[File:Comparison of planets and stars (sheet by sheet) (Oct 2014 update).png|thumb|right|A size [[comparison]] illustration comparing the sizes of various planets and stars. In each grouping after the first, the last object from the previous group is presented as the first object of the following group, to present a continuous sense of comparison.]]
[[File:Size of a Bat skull.jpg|thumb|right|A bat skull next to a [[ruler]] used to measure size.
Size: {{cvt|7|mm}}]]
[[File:Finch Egg.jpg|thumb|right|A [[finch]] egg next to a dime; a person familiar with the size of a dime would thereby have a sense of the size of the egg.]]
[[File:Flickr - Gaspa - Giza, Carlo accarezza la sfinge.jpg|thumb|right|[[Forced perspective]] illusion wherein the perceived size of the Sphinx next to a human is distorted by the incomplete view of both, and the appearance of physical contact between the two.]]
'''Size''' in general is the [[Magnitude (mathematics)|magnitude]] or [[dimension]]s of a thing. More specifically, ''geometrical size'' (or ''spatial size'') can refer to three [[geometrical measures]]: [[length]], [[area]], or [[volume]]. Length can be generalized to other linear dimensions (width, [[height]], [[diameter]], [[perimeter]]).
Size can also be measured in terms of [[mass]], especially when assuming a [[density]] range.
[[File:A cosmic sense of scale.webm|thumb|This animation gives a sense of the scale of some of the known objects in our universe.]]
In mathematical terms, "size is a concept abstracted from the process of measuring by [[Comparison|comparing]] a longer to a shorter".<ref>C. Smoryński, ''History of Mathematics: A Supplement'' (2008), p. 76.</ref> Size is determined by the process of comparing or measuring objects, which results in the determination of the magnitude of a quantity, such as length or mass, relative to a unit of [[measurement]]. Such a magnitude is usually expressed as a numerical value of [[Units of measurement|unit]]s on a previously established [[spatial scale]], such as [[meters]] or [[inches]].
The sizes with which humans tend to be most familiar are body dimensions (measures of [[anthropometry]]), which include measures such as [[human height]] and [[human body weight]]. These measures can, in the aggregate, allow the generation of commercially useful distributions of products that accommodate expected body sizes,<ref>Thomas T. Samaras, ''Human Body Size and the Laws of Scaling'' (2007), p. 3.</ref> as with the creation of [[clothing sizes]] and [[shoe size]]s, and with the standardization of [[Door|door frame]] dimensions, [[ceiling]] heights, and [[bed size]]s. The human experience of size can lead to a psychological tendency towards size bias,<ref name="Matthews 1995 p.">"The notion that bacteria are primitive, unsophisticated organisms stems from what I would call size chauvinism". {{cite book |last=Matthews |first=Clifford |url=https://archive.org/details/cosmicbeginnings0000unse |title=Cosmic beginnings and human ends : where science and religion meet |publisher=Open Court |year=1995 |isbn=978-0-8126-9270-9 |publication-place=Chicago and LaSalle, Ill |page=208 |oclc=31435749 |url-access=registration}}</ref> wherein the relative importance or perceived complexity of organisms and other objects is judged based on their size relative to [[human]]s, and particularly whether this size makes them easy to observe without aid.
==Human perception==
Humans most frequently perceive the size of objects through [[visual cues]].<ref name="Perception">Bennett L. Schwartz, John H. Krantz, ''Sensation and Perception'' (2015), Chapter 7: "Depth and Size Perception", p. 169-199.</ref> One common means of perceiving size is to compare the size of a newly observed object with the size of a familiar object whose size is already known. [[Binocular vision]] gives humans the capacity for [[depth perception]], which can be used to judge which of several objects is closer, and by how much, which allows for some estimation of the size of the more distant object relative to the closer object. This also allows for the estimation of the size of large objects based on comparison of closer and farther parts of the same object. The perception of size can be distorted by manipulating these cues, for example through the creation of [[forced perspective]].
Some measures of size may also be determined by [[sound]]. Visually impaired humans often use [[Human echolocation|echolocation]] to determine features of their surroundings, such as the size of spaces and objects. However, even humans who lack this ability can tell if a space that they are unable to see is large or small from hearing sounds echo in the space. Size can also be determined by [[touch]], which is a process of [[haptic perception]].
The sizes of objects that can not readily be measured merely by sensory input may be evaluated with other kinds of [[measuring instrument]]s. For example, objects too small to be seen with the naked eye may be measured when viewed through a [[microscope]], while objects too large to fit within the [[field of vision]] may be measured using a [[telescope]], or through [[extrapolation]] from known reference points. However, even very advanced measuring devices may still present a limited [[field of view]].
==Terminology==
Objects being described by their relative size are often described as being comparatively big and little, or large and small, although "big and little tend to carry affective and evaluative connotations, whereas large and small tend to refer only to the size of a thing".<ref>John R. Taylor, ''The Mental Corpus: How Language is Represented in the Mind'' (2012), p. 108.</ref> A wide range of other terms exist to describe things by their relative size, with small things being described for example as tiny, miniature, or minuscule, and large things being described as, for example, huge, gigantic, or enormous. Objects are also typically described as tall or short specifically relative to their vertical height, and as long or short specifically relative to their length along other directions. People who have experienced excessive growth and height significantly above average are described as having [[gigantism]]. Outside of humans, [[deep-sea gigantism]] (or abyssal gigantism) is the tendency for species of deep-sea dwelling animals to be larger than their shallower-water relatives across a large taxonomic range, and [[island gigantism]] (or insular gigantism) is a biological phenomenon in which the size of an animal species isolated on an island increases dramatically in comparison to its mainland relatives.
Although the size of an object may be reflected in its [[mass]] or its [[weight]], each of these is a different concept. In scientific contexts, mass refers loosely to the amount of "[[matter]]" in an object (though "matter" may be difficult to define), whereas weight refers to the [[force]] experienced by an object due to [[gravitation|gravity]].<ref>de Silva, G.M.S. (2002), [https://books.google.com/books?id=KbOf_Ap-ijkC&q=%22mass+and+weight+are+often+confused%22 Basic Metrology for ISO 9000 Certification], Butterworth-Heinemann</ref> An object with a mass of 1.0 kilogram will weigh approximately 9.81 newtons ([[Newton (unit)|newton]] is the unit of force, while [[kilogram]] is the unit of mass) on the surface of the [[Earth]] (its mass multiplied by the [[gravity|gravitational field strength]]). Its weight will be less on [[Mars]] (where gravity is weaker), more on [[Saturn]], and negligible in space when far from any significant source of gravity, but it will always have the same mass. Two objects of equal size, however, may have very different mass and weight, depending on the [[Chemical substance|composition]] and [[density]] of the objects. By contrast, if two objects are known to have roughly the same composition, then some information about the size of one can be determined by measuring the size of the other, and determining the difference in weight between the two. For example, if two blocks of wood are equally dense, and it is known that one weighs ten kilograms and the other weighs twenty kilograms, and that the ten kilogram block has a volume of one cubic foot, then it can be deduced that the twenty kilogram block has a volume of two cubic feet.
==Conceptualization and generalization==
The concept of size is often applied to ideas that have no physical reality. In [[mathematics]], [[Magnitude (mathematics)|magnitude]] is the size of a [[mathematical object]], which is an [[abstract object]] with no concrete existence. Magnitude is a property by which the object can be compared as larger or smaller than other objects of the same kind. More formally, an object's magnitude is an [[order theory|ordering]] (or ranking) of the [[class (mathematics)|class]] of objects to which it belongs. There are various other mathematical concepts of size for sets, such as:
* [[measure (mathematics)]], a systematic way to assign to each suitable subset a number
* [[cardinality]] (equal if there is a bijection), of a set is a measure of the "number of elements of the set"
*for well-ordered sets: [[ordinal number]] (equal if there is an order-isomorphism)
In [[statistics]] ([[hypothesis testing]]), the "size" of the test refers to the rate of [[false positives]], denoted by α. In [[astronomy]], the [[Magnitude (astronomy)|magnitude]] of brightness or intensity of a star is measured on a [[logarithmic scale]]. Such a scale is also used to measure the intensity of an [[earthquake]], and this intensity is often referred to as the "size" of the event.<ref>See, e.g., Robert A. Meyers, ''Extreme Environmental Events: Complexity in Forecasting and Early Warning'' (2010), p. 364, stating "[t]he corner frequency scales with the size of the earthquake measured by the seismic moment".</ref> In computing, [[file size]] is a measure of the size of a [[computer]] [[computer file|file]], typically measured in [[byte]]s. The actual amount of [[Computer data storage|disk space]] consumed by the file depends on the [[file system]]. The maximum file size a file system supports depends on the number of [[bit]]s reserved to store size information and the total size of the file system in terms of its capacity to store bits of information.
In [[physics]], the [[Planck length]], denoted {{math|<var>ℓ</var><sub>P</sub>}}, is a unit of [[length]], equal to {{val|1.616199|(97)|e=-35|u=[[metre]]s}}. It is a unit in the system of [[Planck units]], developed by physicist [[Max Planck]]. The Planck length is defined in terms of three [[physical constant|fundamental physical constants]]: the [[speed of light]], the [[Planck constant]], and the [[Newtonian constant of gravitation]]. In contrast, the largest observable thing is the [[observable universe]]. The [[comoving distance]] &ndash; the distance as would be measured at a specific time, including the present &ndash; between [[Earth]] and the edge of the [[observable universe]] is {{convert|14|e9pc|e9ly|order=flip}}, making the [[observable universe#Size|diameter of the observable universe]] about {{convert|28|e9pc|e9ly|order=flip}}.
In [[poetry]], [[fiction]], and other [[literature]], size is occasionally assigned to characteristics that do not have measurable dimensions, such as the metaphorical reference to the size of a person's heart as a shorthand for describing their typical degree of [[kindness]] or [[generosity]]. With respect to physical size, the concept of [[Resizing (fiction)|resizing]] is occasionally presented in [[fairy tales]], [[fantasy]], and [[science fiction]], placing humans in a different context within their natural environment by depicting them as having physically been made exceptionally large or exceptionally small through some fantastic means. A famous example is associated with the fictional character, the [[Grinch]], who was said in the story to have been born with a heart that they say was "two sizes too small", such that when he is later redeemed, his heart grows "three sizes that day", leading cardiologist David Kass to humorously suggest that the rapid growth of the Grinch's heart at the end of the story indicates that the Grinch has the physiology of a [[Burmese python]].<ref>{{cite web|first=Jon|last=Hamilton|url=https://www.npr.org/sections/health-shots/2017/12/22/571998558/heart-2-sizes-too-small-mr-grinch-see-your-cardiologist|title=Heart 2 Sizes Too Small? Mr. Grinch, See Your Cardiologist|website=[[NPR]]|date=December 22, 2017|access-date=December 22, 2017}}</ref>
==See also==
* [[Dimensional instruments]]
* [[Orders of magnitude (length)]]
==References==
{{reflist}}
==External links==
{{Wiktionary|biggity|resize|resized|resizing|size}}
* {{Commons category-inline}}
[[Category:Size| ]]
[[Category:Physical quantities]]