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The microscopic scale () is the scale of objects and events smaller than those that can easily be seen by the
naked eye Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnifying, light-collecting optical instrument, such as a telescope or microscope, or eye protection. Vision corrected to normal ...
, requiring a
lens A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...
or
microscope A microscope () is a laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisibl ...
to see them clearly. In
physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...
, the microscopic scale is sometimes regarded as the scale between the
macroscopic 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. It is the opposite of microscopic. Overview When applied to physical phenomena an ...
and the quantum scale. Microscopic units and measurements are used to classify and describe very small objects. One common microscopic
length scale In physics, length scale is a particular length or distance determined with the precision of at most a few orders of magnitude. The concept of length scale is particularly important because physical phenomena of different length scales cannot aff ...
unit is the
micrometre The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...
(also called a ''micron'') (symbol: μm), which is one millionth of a
metre The metre (British spelling) or meter (American spelling; see spelling differences) (from the French unit , from the Greek noun , "measure"), symbol m, is the primary unit of length in the International System of Units (SI), though its pref ...
.


History

Whilst compound microscopes were first developed in the 1590s, the significance of the microscopic scale was only truly established in the 1600s when Marcello Malphigi and
Antonie van Leeuwenhoek Antonie Philips van Leeuwenhoek ( ; ; 24 October 1632 – 26 August 1723) was a Dutch microbiologist and microscopist in the Golden Age of Dutch science and technology. A largely self-taught man in science, he is commonly known as " the ...
microscopically observed frog lungs and microorganisms. As microbiology was established, the significance of making scientific observations at a microscopic level increased. Published in 1665,
Robert Hooke Robert Hooke FRS (; 18 July 16353 March 1703) was an English polymath active as a scientist, natural philosopher and architect, who is credited to be one of two scientists to discover microorganisms in 1665 using a compound microscope that ...
’s book Micrographia details his microscopic observations including fossils insects, sponges, and plants, which was possible through his development of the compound microscope. During his studies of cork, he discovered plant cells and coined the term ‘
cell Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...
’. Prior to the use of the micro- prefix, other terms were originally incorporated into the International
metric system The metric system is a system of measurement that succeeded the Decimal, decimalised system based on the metre that had been introduced in French Revolution, France in the 1790s. The historical development of these systems culminated in the d ...
in 1795, such as
centi- ''Centi'' (symbol c) is a unit prefix in the metric system denoting a factor of one hundredth. Proposed in 1793, and adopted in 1795, the prefix comes from the Latin , meaning "hundred" (cf. century, cent, percent, centennial). Since 1960, the pr ...
which represented a factor of 10^-2, and
milli- ''Milli'' (symbol m) is a unit prefix in the metric system denoting a factor of one thousandth (10−3). Proposed in 1793, and adopted in 1795, the prefix comes from the Latin , meaning ''one thousand'' (the Latin plural is ). Since 1960, the pre ...
, which represented a factor of 10^-3. Over time the importance of measurements made at the microscopic scale grew, and an instrument named the Millionometre was developed by watch-making company owner Antoine LeCoultre in 1844. This instrument had the ability to precisely measure objects to the nearest micrometre. The
British Association for the Advancement of Science The British Science Association (BSA) is a charity and learned society founded in 1831 to aid in the promotion and development of science. Until 2009 it was known as the British Association for the Advancement of Science (BA). The current Chie ...
committee incorporated the micro- prefix into the newly established CGS system in 1873. The micro- prefix was finally added to the official
SI system The International System of Units, known by the international abbreviation SI in all languages and sometimes pleonastically as the SI system, is the modern form of the metric system and the world's most widely used system of measurement. E ...
in 1960, acknowledging measurements that were made at an even smaller level, denoting a factor of 10^-6.


Biology

By convention, the microscopic scale also includes classes of objects that are most commonly too small to see but of which some members are large enough to be observed with the eye. Such groups include the ''
Cladocera The Diplostraca or Cladocera, commonly known as water fleas, are a superorder of small crustaceans that feed on microscopic chunks of organic matter (excluding some predatory forms). Over 1000 species have been recognised so far, with many more ...
'', planktonic green
algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...
of which ''
Volvox ''Volvox'' is a polyphyletic genus of chlorophyte green algae in the family Volvocaceae. It forms spherical colonies of up to 50,000 cells. They live in a variety of freshwater habitats, and were first reported by Antonie van Leeuwenhoek in 1700 ...
'' is readily observable, and the protozoa of which ''
stentor In Greek mythology, Stentor (Ancient Greek: Στέντωρ; ''gen''.: Στέντορος) was a herald of the Greek forces during the Trojan War. Mythology Stentor is mentioned briefly in Homer's ''Iliad'' in which Hera in the guise of Stent ...
'' can be easily seen without aid. The submicroscopic scale similarly includes objects that are too small to see with an
optical microscope The optical microscope, also referred to as a light microscope, is a type of microscope that commonly uses visible light and a system of lenses to generate magnified images of small objects. Optical microscopes are the oldest design of microsco ...
.


Thermodynamics

In
thermodynamics Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed by the four laws of the ...
and
statistical mechanics In physics, statistical mechanics is a mathematical framework that applies statistical methods and probability theory to large assemblies of microscopic entities. It does not assume or postulate any natural laws, but explains the macroscopic be ...
, the microscopic scale is the scale at which we do not measure or directly observe the precise state of a thermodynamic system – such detailed states of a system are called microstates. We instead measure thermodynamic variables at a
macroscopic 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. It is the opposite of microscopic. Overview When applied to physical phenomena an ...
, i.e. the ''macrostate''.


Levels of Microscopic Scale

As the microscopic scale is covers any object that cannot be seen by the naked eye, yet is visible under a microscope, the range of objects that fall under this scale can be as small as an atom, visible underneath a
transmission electron microscope Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image. The specimen is most often an ultrathin section less than 100 nm thick or a suspension on a gr ...
. Microscope types are often distinguished by their mechanism and application, and can be divided into two general categories.


Light microscopes

Amongst light microscopes, the utilised
objective lens In optical engineering, the objective is the optical element that gathers light from the object being observed and Focus (optics), focuses the ray (optics), light rays to produce a real image. Objectives can be a single Lens (optics), lens or mirr ...
dictates how small of an object can be seen. These varying objective lenses can change the resolving power of the microscope, which determines the shortest distance that somebody is able to distinguish two separate objects through that microscope lens. It is important to note that the resolution between two objects varies from individual to individual, but the strength of the objective lenses can be quantified. The most basic microscope used by
Antonie van Leeuwenhoek Antonie Philips van Leeuwenhoek ( ; ; 24 October 1632 – 26 August 1723) was a Dutch microbiologist and microscopist in the Golden Age of Dutch science and technology. A largely self-taught man in science, he is commonly known as " the ...
in the 1660s, the Simple microscope, uses a singular lens. The user is therefore limited to the magnification allowed by the objective lens. As such, it is usually used to view non-complex items such as maps. Compound light microscopes have a number of variations, including Bright-Field, Dark-Field, Phase-contrast and Fluorescent microscope. Each type functions to serve different purposes, but are all able to have a range of objective lenses, between 4x and 1000x magnification. Due to their mechanisms, they also have an improved resolving power and contrast in comparison to simple microscopes, and can be used to view the structure, shape and motility of a cell and its organisms, which can be as small as 0.1 micrometres.


Electron microscopes

While electron microscopes are still a form of compound microscope, their use of
electron The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no kn ...
beams to illuminate objects varies in mechanism significantly from compound light microscopes, allowing them to have a much higher resolving power, and magnification approximately 10,000 times more than light microscopes. These can be used to view objects such as
atom Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons. Every solid, liquid, gas, and ...
s, which are as small as 0.001 micrometres.


Uses


Forensics

During forensic investigations,
trace evidence Trace evidence is created when objects make contact. The material is often transferred by heat or induced by contact friction. The importance of trace evidence in criminal investigations was shown by Dr. Edmond Locard in the early 20th century. ...
from crime scenes such as blood, fingerprints and fibres can be closely examined under microscopes, even to the extent of determining the age of a trace. Along with other specimens, biological traces can be used to accurately identify individuals present at a location, down to cells found in their blood.


Gemology

When the monetary value of gems is determined, various professions in
gemology Gemology or gemmology is the science dealing with natural and artificial gemstone materials. It is a geoscience and a branch of mineralogy. Some jewelers (and many non-jewelers) are academically trained gemologists and are qualified to identify a ...
require systematic observation of the microscopic physical and optical properties of gemstones. This can involve the use of stereo microscopes to evaluate these qualities, to eventually determine the value of each individual jewel or gemstone. This can be done similarly in evaluations of gold and other metals.


Infrastructure

When assessing road materials, the microscopic composition of the
infrastructure Infrastructure is the set of facilities and systems that serve a country, city, or other area, and encompasses the services and facilities necessary for its economy, households and firms to function. Infrastructure is composed of public and priv ...
is vital in determining the longevity and safety of the road, and the different requirements of varying locations. As chemical properties such as water permeability, structural stability and
heat resistance Thermal resistance is a heat property and a measurement of a temperature difference by which an object or material resists a heat flow. Thermal resistance is the reciprocal of thermal conductance. * (Absolute) thermal resistance ''R'' in kelvin ...
affect the performance of different materials used in pavement mixes, they are taken into consideration when building for roads according to the traffic, weather, supply and budget in that area.


Medicine

In
medicine Medicine is the science and practice of caring for a patient, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting their health. Medicine encompasses a variety of health care pract ...
, diagnoses can be made with the assistance of microscopic observation of patient
biopsies A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a diseas ...
, such as cancer cells.
Pathology Pathology is the study of the causes and effects of disease or injury. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used in ...
and
cytology Cell biology (also cellular biology or cytology) is a branch of biology that studies the structure, function, and behavior of cells. All living organisms are made of cells. A cell is the basic unit of life that is responsible for the living and ...
reports include a microscopic description, which consists of analyses performed using microscopes, histochemical stains or
flow cytometry Flow cytometry (FC) is a technique used to detect and measure physical and chemical characteristics of a population of cells or particles. In this process, a sample containing cells or particles is suspended in a fluid and injected into the flo ...
. These methods can determine the structure of the diseased tissue and the severity of the disease, and early detection is possible through identification of microscopic indications of illness.


Microscopic Scale in the laboratory

Whilst use of the microscopic scale has many roles and purposes in the scientific field, there are many biochemical patterns observed microscopically that have contributed significantly to the understanding of how human life relies on microscopic structures to function and live.


Founding experiments

Antonie van Leeuwenhoek was not only a contributor to the invention of the microscope, he is also referred to as the “father of Microbiology”. This is due to his significant contributions in the initial observation and documentation of
unicellular organism A unicellular organism, also known as a single-celled organism, is an organism that consists of a single cell, unlike a multicellular organism that consists of multiple cells. Organisms fall into two general categories: prokaryotic organisms and ...
s such as bacteria and spermatozoa, and microscopic human tissue such as muscle fibres and capillaries.


Biochemistry


Human Cells

Genetic manipulation of energy-regulating
mitochondria A mitochondrion (; ) is an organelle found in the Cell (biology), cells of most Eukaryotes, such as animals, plants and Fungus, fungi. Mitochondria have a double lipid bilayer, membrane structure and use aerobic respiration to generate adenosi ...
under microscopic principles has also been found to extend organism lifespan, tackling age-associated issues in humans such as
Parkinson's Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...
,
Alzheimer's Alzheimer's disease (AD) is a neurodegenerative disease that usually starts slowly and progressively worsens. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As t ...
and
multiple sclerosis Multiple (cerebral) sclerosis (MS), also known as encephalomyelitis disseminata or disseminated sclerosis, is the most common demyelinating disease, in which the insulating covers of nerve cells in the brain and spinal cord are damaged. This d ...
. By increasing the amount of energy products made by mitochondria, the lifespan of its cell, and thus organism, increases.


DNA

Microscopic analysis of the spatial distribution of points within DNA
heterochromatin Heterochromatin is a tightly packed form of DNA or '' condensed DNA'', which comes in multiple varieties. These varieties lie on a continue between the two extremes of constitutive heterochromatin and facultative heterochromatin. Both play a role ...
centromere The centromere links a pair of sister chromatids together during cell division. This constricted region of chromosome connects the sister chromatids, creating a short arm (p) and a long arm (q) on the chromatids. During mitosis, spindle fibers a ...
s emphasise the role of the centromeric regions of chromosomes in nuclei undergoing the
interphase Interphase is the portion of the cell cycle that is not accompanied by visible changes under the microscope, and includes the G1, S and G2 phases. During interphase, the cell grows (G1), replicates its DNA (S) and prepares for mitosis (G2). A c ...
part of cell
mitosis In cell biology, mitosis () is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is mainta ...
. Such microscopic observations suggest nonrandom distribution and precise structure of centromeres during mitosis is a vital contributor to successful cell function and growth, even in cancer cells.


Chemistry and Physics

The
entropy Entropy is a scientific concept, as well as a measurable physical property, that is most commonly associated with a state of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodynam ...
and disorder of the universe can be observed at a microscopic scale, with reference to the second and third law of thermodynamics. In some cases, this can involve calculating the entropy change within a container of expanding gas molecules and relating it to the entropy change of its environment and the universe.


Ecology

Ecologists monitor the state of an ecosystem over time by identifying microscopic features within the environment. This includes the temperature and tolerance of microorganisms such as ciliates, and their interactions with othrt Protozoa. Additionally, microscopic factors such as movement and motility can be observed in water samples of that ecosystem.


Geology

Branches of
geology Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ear ...
involve the study of the Earth's structure at a microscopic level. Physical characteristics of rocks are recorded, and in
petrography Petrography is a branch of petrology that focuses on detailed descriptions of rocks. Someone who studies petrography is called a petrographer. The mineral content and the textural relationships within the rock are described in detail. The classi ...
there is a specific focus on the examination of microscopic details of rocks. Similar to scanning electron microscopes, electron microprobes can be used in
petrology Petrology () is the branch of geology that studies rocks and the conditions under which they form. Petrology has three subdivisions: igneous, metamorphic, and sedimentary petrology. Igneous and metamorphic petrology are commonly taught together ...
to observe the condition that allows rocks to form, which can inform the origin of these samples. In
structural geology Structural geology is the study of the three-dimensional distribution of rock units with respect to their deformational histories. The primary goal of structural geology is to use measurements of present-day rock geometries to uncover informatio ...
, petrographic microscopes allow the study of rock microstructures, to determine how geologic features such as
tectonic plates Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large te ...
affect the likelihood of earthquakes and groundwater movement.


Current research

There have been both advances in microscopic technology, and discoveries in other areas of knowledge as a result of microscopic technology.


Alzheimer’s and Parkinson’s Disease

In conjunction with fluorescent tagging, molecular details in singular
amyloid Amyloids are aggregates of proteins characterised by a Fibril, fibrillar morphology of 7–13 Nanometer, nm in diameter, a beta sheet (β-sheet) Secondary structure of proteins, secondary structure (known as cross-β) and ability to be Staining, ...
proteins can be studied through new light microscopy techniques, and their relation to Alzheimer's and Parkinson's disease.


Atomic force microscopy

Other improvements in light microscopy include the ability to view sub-wavelength, nanosized objects. Nanoscale imaging via
atomic force microscopy Atomic force microscopy (AFM) or scanning force microscopy (SFM) is a very-high-resolution type of scanning probe microscopy (SPM), with demonstrated resolution on the order of fractions of a nanometer, more than 1000 times better than the op ...
has also been improved to allow a more precise observation of small amounts of complex objects, such as
cell membrane The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment ( ...
s.


Renewable energy

Coherent microscopic patterns discovered in chemical systems support ideas of the resilience of certain substances against
entropic Entropy is a scientific concept, as well as a measurable physical property, that is most commonly associated with a state of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodynam ...
environments. This research is being utilised to inform the productions of
solar fuel A solar fuel is a synthetic chemical fuel produced from solar energy. Solar fuels can be produced through photochemical (i.e. activation of certain chemical reactions by photons), photobiological (i.e., artificial photosynthesis), thermochemical ( ...
s, and the improvement of renewable energy.


Microscopic instrument - Micronium

A microscopic instrument called the Micronium has also been developed through
micromechanics Micromechanics (or, more precisely, micromechanics of materials) is the analysis of composite or heterogeneous materials on the level of the individual constituents that constitute these materials. Aims of micromechanics of materials Heterogeneo ...
, consisting of springs the thickness of human hair being plucked by microscopic comb drives. This is a very minimal movement that produces an audible noise to the human ear, which was not previously done by past attempts with microscopic instruments.


See also

*
Macroscopic 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. It is the opposite of microscopic. Overview When applied to physical phenomena an ...
*
Microorganism A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...
*
Van Leeuwenhoek's microscopes A van is a type of road vehicle used for transporting goods or people. Depending on the type of van, it can be bigger or smaller than a pickup truck and SUV, and bigger than a common car. There is some varying in the scope of the word across th ...
* Van Leeuwenhoek's microscopic discovery of microbial life (microorganisms)


References

{{DEFAULTSORT:Microscopic Scale Concepts in physics Orders of magnitude