When applied to physical phenomena and bodies, the macroscopic scale describes things as a person can directly perceive them, without the aid of magnifying devices. This is in contrast to observations (microscopy) or theories (microphysics, statistical physics) of objects of geometric lengths smaller than perhaps some hundreds of micrometers.
A macroscopic view of a ball is just that: a ball. A microscopic view could reveal a thick round skin seemingly composed entirely of puckered cracks and fissures (as viewed through a microscope) or, further down in scale, a collection of molecules in a roughly spherical shape (as viewed through an electron microscope). An example of a physical theory that takes a deliberately macroscopic viewpoint is thermodynamics. An example of a topic that extends from macroscopic to microscopic viewpoints is histology.
Not quite by the distinction between macroscopic and microscopic, classical and quantum mechanics are theories that are distinguished in a subtly different way.[3] At first glance one might think of them as differing simply in the size of objects that they describe, classical objects being considered far larger as to mass and geometrical size than quantal objects, for example a football versus a fine particle of dust. More refined consideration distinguishes classical and quantum mechanics on the basis that classical mechanics fails to recognize that matter and energy cannot be divided into infinitesimally small parcels, so that ultimately fine division reveals irreducibly granular features. The criterion of fineness is whether or not the interactions are described in terms of Planck's constant. Roughly speaking, classical mechanics considers particles in mathematically idealized terms even as fine as geometrical points with no magnitude, still having their finite masses. Classical mechanics also considers mathematically idealized extended materials as geometrically continuously substantial. Such idealizations are useful for most everyday calculations, but may fail entirely for molecules, atoms, photons, and other elementary particles. In many ways, classical mechanics can be considered a mainly macroscopic theory. On the much smaller scale of atoms and molecules, classical mechanics may fail, and the interactions of particles are then described by quantum mechanics. Near the absolute minimum of temperature, the Bose–Einstein condensate exhibits effects on macroscopic scale that demand description by quantum mechanics.
In the Quantum Measurement Problem the issue of what constitutes macroscopic and what constitutes the quantum world is unresolved and possibly unsolvable. The related Correspondence Principle can be articulated thus: every macroscopic phenomena can be formulated as a problem in quantum theory. A violation of the Correspondence Principle would thus ensure an empirical distinction between the macroscopic and the quantum.
The term "megascopic" is a synonym. "Macroscopic" may also refer to a "larger view", namely a view available only from a large perspective (a hypothetical "macroscope"). A macroscopic position could be considered the "big picture".
High energy physics compared to low energy physics
Particle physics, dealing with the smallest physical systems, is also known as high energy physics. Physics of larger length scales, including the macroscopic scale, is also known as low energy physics. Intuitively, it might seem incorrect to associate "high energy" with the physics of very small, lowmass-energy systems, like subatomic particles. By comparison, one gram of hydrogen, a macroscopic system, has ~ 6×1023 times[4] the mass-energy of a single proton, a central object of study in high energy physics. Even an entire beam of protons circulated in the Large Hadron Collider, a high energy physics experiment, contains ~ 3.23×1014 protons,[5] each with 6.5×1012eV of energy, for a total beam energy of ~ 2.1×1027 eV or ~ 336.4 MJ, which is still ~ 2.7×105 times lower than the mass-energy of a single gram of hydrogen. Yet, the macroscopic realm is "low energy physics", while that of quantum particles is "high energy physics".
The reason for this is that the "high energy" refers to energy at the quantum particle level. While macroscopic systems indeed have a larger total energy content than any of their constituent quantum particles, there can be no experiment or other observation of this total energy without extracting the respective amount of energy from each of the quantum particles – which is exactly the domain of high energy physics. Daily experiences of matter and the Universe are characterized by very low energy. For example, the photon energy of visible light is about 1.8 to 3.2 eV. Similarly, the bond-dissociation energy of a carbon-carbon bond is about 3.6 eV. This is the energy scale manifesting at the macroscopic level, such as in chemical reactions. Even photons with far higher energy, gamma rays of the kind produced in radioactive decay, have photon energy that is almost always between 105 eV and 107 eV – still two orders of magnitude lower than the mass-energy of a single proton. Radioactive decay gamma rays are considered as part of nuclear physics, rather than high energy physics.
Finally, when reaching the quantum particle level, the high energy domain is revealed. The proton has a mass-energy of ~ 9.4×108 eV; some other massive quantum particles, both elementary and hadronic, have yet higher mass-energies. Quantum particles with lower mass-energies are also part of high energy physics; they also have a mass-energy that is far higher than that at the macroscopic scale (such as electrons), or are equally involved in reactions at the particle level (such as neutrinos). Relativistic effects, as in particle accelerators and cosmic rays, can further increase the accelerated particles' energy by many orders of magnitude, as well as the total energy of the particles emanating from their collision and annihilation.
^Reif, F. (1965). Fundamentals of Statistical and Thermal Physics (International student ed.). Boston: McGraw-Hill. p. 2. ISBN007-051800-9. we shall call a system "macroscopic" (i.e., "large scale") when it is large enough to be visible in the ordinary sense (say greater than 1 micron, so that it can at least be observed with a microscope using ordinary light).
^Jaeger, Gregg (September 2014). "What in the (quantum) world is macroscopic?". American Journal of Physics. 82 (9): 896–905. Bibcode:2014AmJPh..82..896J. doi:10.1119/1.4878358.
^Jaeger, Gregg (September 2014). "What in the (quantum) world is macroscopic?". American Journal of Physics. 82 (9): 896–905. Bibcode:2014AmJPh..82..896J. doi:10.1119/1.4878358.
^"CODATA Value: Avogadro constant". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 13 December 2016.
^"Beam Requirements and Fundamental Choices" (PDF). CERN Engineering & Equipment Data Management Service (EDMS). Retrieved 10 December 2016.
January 31, 2023
macroscopic, scale, macroscopic, redirects, here, confused, with, macroscope, confused, with, microscopic, scale, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, . Macroscopic redirects here Not to be confused with Macroscope Not to be confused with Microscopic scale This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Macroscopic scale news newspapers books scholar JSTOR February 2013 Learn how and when to remove this template message The macroscopic scale is the length scale on which objects or phenomena are large enough to be visible with the naked eye without magnifying optical instruments 1 2 It is the opposite of microscopic Contents 1 Overview 2 High energy physics compared to low energy physics 3 See also 4 ReferencesOverview EditWhen applied to physical phenomena and bodies the macroscopic scale describes things as a person can directly perceive them without the aid of magnifying devices This is in contrast to observations microscopy or theories microphysics statistical physics of objects of geometric lengths smaller than perhaps some hundreds of micrometers A macroscopic view of a ball is just that a ball A microscopic view could reveal a thick round skin seemingly composed entirely of puckered cracks and fissures as viewed through a microscope or further down in scale a collection of molecules in a roughly spherical shape as viewed through an electron microscope An example of a physical theory that takes a deliberately macroscopic viewpoint is thermodynamics An example of a topic that extends from macroscopic to microscopic viewpoints is histology Not quite by the distinction between macroscopic and microscopic classical and quantum mechanics are theories that are distinguished in a subtly different way 3 At first glance one might think of them as differing simply in the size of objects that they describe classical objects being considered far larger as to mass and geometrical size than quantal objects for example a football versus a fine particle of dust More refined consideration distinguishes classical and quantum mechanics on the basis that classical mechanics fails to recognize that matter and energy cannot be divided into infinitesimally small parcels so that ultimately fine division reveals irreducibly granular features The criterion of fineness is whether or not the interactions are described in terms of Planck s constant Roughly speaking classical mechanics considers particles in mathematically idealized terms even as fine as geometrical points with no magnitude still having their finite masses Classical mechanics also considers mathematically idealized extended materials as geometrically continuously substantial Such idealizations are useful for most everyday calculations but may fail entirely for molecules atoms photons and other elementary particles In many ways classical mechanics can be considered a mainly macroscopic theory On the much smaller scale of atoms and molecules classical mechanics may fail and the interactions of particles are then described by quantum mechanics Near the absolute minimum of temperature the Bose Einstein condensate exhibits effects on macroscopic scale that demand description by quantum mechanics In the Quantum Measurement Problem the issue of what constitutes macroscopic and what constitutes the quantum world is unresolved and possibly unsolvable The related Correspondence Principle can be articulated thus every macroscopic phenomena can be formulated as a problem in quantum theory A violation of the Correspondence Principle would thus ensure an empirical distinction between the macroscopic and the quantum In pathology macroscopic diagnostics generally involves gross pathology in contrast to microscopic histopathology The term megascopic is a synonym Macroscopic may also refer to a larger view namely a view available only from a large perspective a hypothetical macroscope A macroscopic position could be considered the big picture High energy physics compared to low energy physics EditParticle physics dealing with the smallest physical systems is also known as high energy physics Physics of larger length scales including the macroscopic scale is also known as low energy physics Intuitively it might seem incorrect to associate high energy with the physics of very small low mass energy systems like subatomic particles By comparison one gram of hydrogen a macroscopic system has 6 1023 times 4 the mass energy of a single proton a central object of study in high energy physics Even an entire beam of protons circulated in the Large Hadron Collider a high energy physics experiment contains 3 23 1014 protons 5 each with 6 5 1012 eV of energy for a total beam energy of 2 1 1027 eV or 336 4 MJ which is still 2 7 105 times lower than the mass energy of a single gram of hydrogen Yet the macroscopic realm is low energy physics while that of quantum particles is high energy physics The reason for this is that the high energy refers to energy at the quantum particle level While macroscopic systems indeed have a larger total energy content than any of their constituent quantum particles there can be no experiment or other observation of this total energy without extracting the respective amount of energy from each of the quantum particles which is exactly the domain of high energy physics Daily experiences of matter and the Universe are characterized by very low energy For example the photon energy of visible light is about 1 8 to 3 2 eV Similarly the bond dissociation energy of a carbon carbon bond is about 3 6 eV This is the energy scale manifesting at the macroscopic level such as in chemical reactions Even photons with far higher energy gamma rays of the kind produced in radioactive decay have photon energy that is almost always between 105 eV and 107 eV still two orders of magnitude lower than the mass energy of a single proton Radioactive decay gamma rays are considered as part of nuclear physics rather than high energy physics Finally when reaching the quantum particle level the high energy domain is revealed The proton has a mass energy of 9 4 108 eV some other massive quantum particles both elementary and hadronic have yet higher mass energies Quantum particles with lower mass energies are also part of high energy physics they also have a mass energy that is far higher than that at the macroscopic scale such as electrons or are equally involved in reactions at the particle level such as neutrinos Relativistic effects as in particle accelerators and cosmic rays can further increase the accelerated particles energy by many orders of magnitude as well as the total energy of the particles emanating from their collision and annihilation See also EditHigh energy physics Microscopic scale Quantum realmReferences Edit Reif F 1965 Fundamentals of Statistical and Thermal Physics International student ed Boston McGraw Hill p 2 ISBN 007 051800 9 we shall call a system macroscopic i e large scale when it is large enough to be visible in the ordinary sense say greater than 1 micron so that it can at least be observed with a microscope using ordinary light Jaeger Gregg September 2014 What in the quantum world is macroscopic American Journal of Physics 82 9 896 905 Bibcode 2014AmJPh 82 896J doi 10 1119 1 4878358 Jaeger Gregg September 2014 What in the quantum world is macroscopic American Journal of Physics 82 9 896 905 Bibcode 2014AmJPh 82 896J doi 10 1119 1 4878358 CODATA Value Avogadro constant The NIST Reference on Constants Units and Uncertainty US National Institute of Standards and Technology June 2015 Retrieved 13 December 2016 Beam Requirements and Fundamental Choices PDF CERN Engineering amp Equipment Data Management Service EDMS Retrieved 10 December 2016 Retrieved from https en wikipedia org w index php title Macroscopic scale amp oldid 1084061945, wikipedia, wiki, book, books, library,
