Macroscopic scale

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"Macroscopic" redirects here. Not to be confused with Macroscope.
Not to be confused with Microscopic scale.

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.

Overview

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 (

statistical physics) of objects of geometric lengths smaller than perhaps some hundreds of micrometers
.

A macroscopic view of 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,

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

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

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

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

References

  1. 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).
  2. doi:10.1119/1.4878358
    .
  3. doi:10.1119/1.4878358
    .
  4. ^ "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.
  5. ^ "Beam Requirements and Fundamental Choices" (PDF). CERN Engineering & Equipment Data Management Service (EDMS). Retrieved 10 December 2016.
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