Size

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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. Megalodon-Carcharodon-Scale-Chart-SVG.svg
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.
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. Comparison of planets and stars (sheet by sheet) (Oct 2014 update).png
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.
A bat skull next to a ruler used to measure size. Size: 7 mm (0.28 in) Size of a Bat skull.jpg
A bat skull next to a ruler used to measure size. Size: 7 mm (0.28 in)
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. Finch Egg.jpg
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.
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. Flickr - Gaspa - Giza, Carlo accarezza la sfinge.jpg
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 or dimensions 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.

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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 comparing a longer to a shorter". [1] 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 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, [2] as with the creation of clothing sizes and shoe sizes, and with the standardization of door frame dimensions, ceiling heights, and bed sizes. The human experience of size can lead to a psychological tendency towards size bias, [3] wherein the relative importance or perceived complexity of organisms and other objects is judged based on their size relative to humans, 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. [4] 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 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 instruments. 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". [5] 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 gravity. [6] An object with a mass of 1.0 kilogram will weigh approximately 9.81 newtons (newton is the unit of force, while kilogram is the unit of mass) on the surface of the Earth (its mass multiplied by the 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 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 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 ordering (or ranking) of the class of objects to which it belongs. There are various other mathematical concepts of size for sets, such as:

In statistics (hypothesis testing), the "size" of the test refers to the rate of false positives, denoted by α. In astronomy, the 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. [7] In computing, file size is a measure of the size of a computer file, typically measured in bytes. The actual amount of disk space consumed by the file depends on the file system. The maximum file size a file system supports depends on the number of bits 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 ℓP, is a unit of length, equal to 1.616199(97)×10−35  metres . It is a unit in the system of Planck units, developed by physicist Max Planck. The Planck length is defined in terms of three 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 – the distance as would be measured at a specific time, including the present – between Earth and the edge of the observable universe is 46 billion light-years (14×10^9 pc), making the diameter of the observable universe about 91 billion light-years (28×10^9 pc).

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 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. [8]

See also

Related Research Articles

Length is a measure of distance. In the International System of Quantities, length is a quantity with dimension distance. In most systems of measurement a base unit for length is chosen, from which all other units are derived. In the International System of Units (SI) system the base unit for length is the metre.

<span class="mw-page-title-main">Measurement</span> Process of assigning numbers to objects or events

Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events. In other words, measurement is a process of determining how large or small a physical quantity is as compared to a basic reference quantity of the same kind. The scope and application of measurement are dependent on the context and discipline. In 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. However, in other fields such as statistics as well as the social and behavioural sciences, measurements can have multiple levels, which would include nominal, ordinal, interval and ratio scales.

<span class="mw-page-title-main">Mass</span> Amount of matter present in an object

Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a body, until the discovery of the atom and particle physics. It was found that different atoms and different elementary particles, theoretically with the same amount of matter, have nonetheless different masses. Mass in modern physics has multiple definitions which are conceptually distinct, but physically equivalent. Mass can be experimentally defined as a measure of the body's inertia, meaning the resistance to acceleration when a net force is applied. The object's mass also determines the strength of its gravitational attraction to other bodies.

A physical constant, sometimes fundamental physical constant or universal constant, is a physical quantity that cannot be explained by a theory and therefore must be measured experimentally. It is distinct from a mathematical constant, which has a fixed numerical value, but does not directly involve any physical measurement.

<span class="mw-page-title-main">Volume</span> Quantity of three-dimensional space

Volume is a measure of regions in three-dimensional space. It is often quantified numerically using SI derived units or by various imperial or US customary units. The definition of length and height (cubed) is interrelated with volume. The volume of a container is generally understood to be the capacity of the container; i.e., the amount of fluid that the container could hold, rather than the amount of space the container itself displaces. By metonymy, the term "volume" sometimes is used to refer to the corresponding region.

<span class="mw-page-title-main">Weight</span> Force on a mass due to gravity

In science and engineering, the weight of an object is a quantity associated with the gravitational force exerted on the object by other objects in its environment, although there is some variation and debate as to the exact definition.

<span class="mw-page-title-main">Metric system</span> Metre-based systems of measurement

The metric system is a decimal-based system of measurement. The current international standard for the metric system is the International System of Units, in which all units can be expressed in terms of seven base units: the metre (m), kilogram (kg), second (s), ampere (A), kelvin (K), mole (mol), and candela (cd). These can be made into larger or smaller units with the use of metric prefixes.

<span class="mw-page-title-main">Newton (unit)</span> Unit of force in physics

The newton is the unit of force in the International System of Units (SI). Expressed in terms of SI base units, it is 1 kg⋅m/s2, the force that accelerates a mass of one kilogram at one metre per second squared.

The elementary charge, usually denoted by e, is a fundamental physical constant, defined as the electric charge carried by a single proton or, equivalently, the magnitude of the negative electric charge carried by a single electron, which has charge −1 e.

<span class="mw-page-title-main">Human scale</span> Concept that takes people as the primary measure of development

Human scale is the set of physical qualities, and quantities of information, characterizing the human body, its motor, sensory, or mental capabilities, and human social institutions.

Size is the concept of how big or small something is. It may also refer to:

Quantity or amount is a property that can exist as a multitude or magnitude, which illustrate discontinuity and continuity. Quantities can be compared in terms of "more", "less", or "equal", or by assigning a numerical value multiple of a unit of measurement. Mass, time, distance, heat, and angle are among the familiar examples of quantitative properties.

<span class="mw-page-title-main">Kibble balance</span> Electromechanical weight measuring instrument

A Kibble balance is an electromechanical measuring instrument that measures the weight of a test object very precisely by the electric current and voltage needed to produce a compensating force. It is a metrological instrument that can realize the definition of the kilogram unit of mass based on fundamental constants.

A system of units of measurement, also known as a system of units or system of measurement, is a collection of units of measurement and rules relating them to each other. Systems of measurement have historically been important, regulated and defined for the purposes of science and commerce. Instances in use include the International System of Units or SI, the British imperial system, and the United States customary system.

Grammage and basis weight, in the pulp and paper industry, are the area density of a paper product, that is, its mass per unit of area. Two ways of expressing grammage are commonly used:

<span class="mw-page-title-main">Mass versus weight</span> Distinction between mass and weight

In common usage, the mass of an object is often referred to as its weight, though these are in fact different concepts and quantities. Nevertheless, one object will always weigh more than another with less mass if both are subject to the same gravity.

<span class="mw-page-title-main">2019 revision of the SI</span> Definition of the units kg, A, K and mol

In 2019, four of the seven SI base units specified in the International System of Quantities were redefined in terms of natural physical constants, rather than human artefacts such as the standard kilogram. Effective 20 May 2019, the 144th anniversary of the Metre Convention, the kilogram, ampere, kelvin, and mole are now defined by setting exact numerical values, when expressed in SI units, for the Planck constant, the elementary electric charge, the Boltzmann constant, and the Avogadro constant, respectively. The second, metre, and candela had previously been redefined using physical constants. The four new definitions aimed to improve the SI without changing the value of any units, ensuring continuity with existing measurements. In November 2018, the 26th General Conference on Weights and Measures (CGPM) unanimously approved these changes, which the International Committee for Weights and Measures (CIPM) had proposed earlier that year after determining that previously agreed conditions for the change had been met. These conditions were satisfied by a series of experiments that measured the constants to high accuracy relative to the old SI definitions, and were the culmination of decades of research.

In particle physics and physical cosmology, Planck units are a system of units of measurement defined exclusively in terms of four universal physical constants: c, G, ħ, and kB. Expressing one of these physical constants in terms of Planck units yields a numerical value of 1. They are a system of natural units, defined using fundamental properties of nature rather than properties of a chosen prototype object. Originally proposed in 1899 by German physicist Max Planck, they are relevant in research on unified theories such as quantum gravity.

This glossary of physics is a list of definitions of terms and concepts relevant to physics, its sub-disciplines, and related fields, including mechanics, materials science, nuclear physics, particle physics, and thermodynamics. For more inclusive glossaries concerning related fields of science and technology, see Glossary of chemistry terms, Glossary of astronomy, Glossary of areas of mathematics, and Glossary of engineering.

<span class="mw-page-title-main">Alternative approaches to redefining the kilogram</span>

The scientific community examined several approaches to redefining the kilogram before deciding on a revision of the SI in November 2018. Each approach had advantages and disadvantages.

References

  1. ↑ C. Smoryński, History of Mathematics: A Supplement (2008), p. 76.
  2. ↑ Thomas T. Samaras, Human Body Size and the Laws of Scaling (2007), p. 3.
  3. ↑ "The notion that bacteria are primitive, unsophisticated organisms stems from what I would call size chauvinism". Matthews, Clifford (1995). Cosmic beginnings and human ends : where science and religion meet . Chicago and LaSalle, Ill: Open Court. p. 208. ISBN   978-0-8126-9270-9. OCLC   31435749.
  4. ↑ Bennett L. Schwartz, John H. Krantz, Sensation and Perception (2015), Chapter 7: "Depth and Size Perception", p. 169-199.
  5. ↑ John R. Taylor, The Mental Corpus: How Language is Represented in the Mind (2012), p. 108.
  6. ↑ de Silva, G.M.S. (2002), Basic Metrology for ISO 9000 Certification, Butterworth-Heinemann
  7. ↑ 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".
  8. ↑ Hamilton, Jon (December 22, 2017). "Heart 2 Sizes Too Small? Mr. Grinch, See Your Cardiologist". NPR . Retrieved December 22, 2017.
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