# Microscopic scale

The microscopic scale (from Greek: μικρός, mikrós, "small" and σκοπέω, skopéō "look") is the scale of objects and events smaller than those that can easily be seen by the naked eye, requiring a lens or microscope to see them clearly.[1] In physics, the microscopic scale is sometimes regarded as the scale between the macroscopic scale and the quantum scale.[2][3] Microscopic units and measurements are used to classify and describe very small objects. One common microscopic length scale unit is the micrometre (also called a micron) (symbol: μm), which is one millionth of a metre.

## 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, planktonic green algae of which Volvox is readily observable, and the protozoa of which stentor can be easily seen without aid. The submicroscopic scale similarly includes objects that are too small to see with an optical microscope.[4]

## Thermodynamics

In thermodynamics and statistical mechanics, 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, i.e. the macrostate.

## References

1. ^ "The microscopic scale". Science Learning Hub. The University of Waikato. Archived from the original on 20 April 2016. Retrieved 31 March 2016.
2. ^ 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.
3. ^ Reif, F. (1965). Fundamentals of Statistical and Thermal Physics (International student edition. ed.). Boston: McGraw-Hill. p. 2. ISBN 007-051800-9. We shall call a system 'microscopic' (i.e., 'small scale') if it is roughly of atomic dimensions or smaller (say of the order of 10 Å or less).
4. ^ 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.
Asperity (materials science)

In materials science, asperity, defined as "unevenness of surface, roughness, ruggedness" (OED, from the Latin asper—"rough"), has implications (for example) in physics and seismology. Smooth surfaces, even those polished to a mirror finish, are not truly smooth on a microscopic scale. They are rough, with sharp, rough or rugged projections, termed "asperities". Surface asperities exist across multiple scales, often in a self affine or fractal geometry. The fractal dimension of these structures has been correlated with the contact mechanics exhibited at an interface in terms of friction and contact stiffness.

When two macroscopically smooth surfaces come into contact, initially they only touch at a few of these asperity points. These cover only a very small portion of the surface area. Friction and wear originate at these points, and thus understanding their behavior becomes important when studying materials in contact. When the surfaces are subjected to a compressive load, the asperities deform through elastic and plastic modes, increasing the contact area between the two surfaces until the contact area is sufficient to support the load.

The relationship between frictional interactions and asperity geometry is complex and poorly understood. It has been reported that an increased roughness may under certain circumstances result in weaker frictional interactions while smoother surfaces may in fact exhibit high levels of friction owing to high levels of true contact.The Archard equation provides a simplified model of asperity deformation when materials in contact are subject to a force. Due to the ubiquitous presence of deformable asperities in self affine hierarchical structures, the true contact area at an interface exhibits a linear relationship with the applied normal load.

Contact area

When two objects touch, only a certain portion of their surface areas will be in contact with each other. This area of true contact, most often constitutes only a very small fraction of the apparent or nominal contact area. In relation to two contacting objects, the term Contact area refers to the fraction of the nominal area that consists of atoms of one object in true contact with the atoms of the other object. Because objects are never perfectly flat due to asperities, the actual contact area (on a microscopic scale) is usually much less than the contact area apparent on a macroscopic scale. Contact area may depend on the normal force between the two objects due to deformation. The contact area depends on the geometry of the contacting bodies, the load, and the material properties. The contact area between the two parallel cylinders is a narrow rectangle. Two, non-parallel cylinders have an elliptical contact area, unless the cylinders are crossed at 90 degrees, in which case they have a circular contact area. Two spheres also have a circular contact area.

Genetic analysis

Genetic analysis is the overall process of studying and researching in fields of science that involve genetics and molecular biology. There are a number of applications that are developed from this research, and these are also considered parts of the process. The base system of analysis revolves around general genetics. Basic studies include identification of genes and inherited disorders. This research has been conducted for centuries on both a large-scale physical observation basis and on a more microscopic scale.

Genetic analysis can be used generally to describe methods both used in and resulting from the sciences of genetics and molecular biology, or to applications resulting from this research.

Genetic analysis may be done to identify genetic/inherited disorders and also to make a differential diagnosis in certain somatic diseases such as cancer. Genetic analyses of cancer include detection of mutations, fusion genes, and DNA copy number changes.

ISIS neutron source

ISIS Neutron and Muon Source is a pulsed neutron and muon source. It is situated at the Rutherford Appleton Laboratory of the Science and Technology Facilities Council, on the Harwell Science and Innovation Campus in Oxfordshire, United Kingdom. It uses the techniques of muon spectroscopy and neutron scattering to probe the structure and dynamics of condensed matter on a microscopic scale ranging from the subatomic to the macromolecular.

Hundreds of experiments are performed every year the facility by researchers from around the world, in diverse science areas such as physics, chemistry, materials engineering, earth sciences, biology and archaeology.

Indentation hardness

Indentation hardness tests are used in mechanical engineering to determine the hardness of a material to deformation. Several such tests exist, wherein the examined material is indented until an impression is formed; these tests can be performed on a macroscopic or microscopic scale.

When testing metals, indentation hardness correlates roughly linearly with tensile strength., but it is an imperfect correlation often limited to small ranges of strength and hardness for each indentation geometry. This relation permits economically important nondestructive testing of bulk metal deliveries with lightweight, even portable equipment, such as hand-held Rockwell hardness testers.

Kees Boeke

Cornelis Boeke (25 September 1884, Alkmaar – 3 July 1966, Abcoude), usually known as Kees Boeke, was a Dutch reformist educator, Quaker missionary and pacifist. He is best known for his popular essay/book Cosmic View (1957) which presents a seminal view of the universe, from the galactic to the microscopic scale, and which inspired several films.

Boeke tried to reform education by allowing the children to contribute their ideas. He called this process sociocracy and regarded schools as workshops, with pupils as workers, and teachers as co-workers. Based on Quaker ideas, he wanted the children to respect democracy. In 1926, he founded a school in Bilthoven, which he led until 1954. As a child, the later Dutch Queen Beatrix attended the school.

Laser capture microdissection

Laser capture microdissection (LCM), also called microdissection, laser microdissection (LMD), or laser-assisted microdissection (LMD or LAM), is a method for isolating specific cells of interest from microscopic regions of tissue/cells/organisms (dissection on a microscopic scale with the help of a laser).

Microphotograph

Microphotographs are photographs shrunk to microscopic scale. Microphotography is the art of making such images. Applications of microphotography include espionage such as in the Hollow Nickel Case, where they are known as microfilm.

Using the daguerreotype process, John Benjamin Dancer was one of the first to produce microphotographs, in 1839.

He achieved a reduction ratio of 160:1. Dancer perfected his reduction procedures with Frederick Scott Archer’s wet collodion process, developed in 1850–51, but he dismissed his decades-long work on microphotographs as a personal hobby, and did not document his procedures. The idea that microphotography could be no more than a novelty was an opinion shared by the 1858 Dictionary of Photography, which called the process "somewhat trifling and childish."Novelty viewing devices such as Stanhopes were once a popular way to carry and view microphotographs.An important application of microphotography is in microforms.

Microphotonics

Microphotonics is a branch of technology that deals with directing light on a microscopic scale and is used in optical networking. Particularly, it refers to the branch of technology that deals with wafer-level integrated devices and systems that emit, transmit, detect, and process light along with other forms of radiant energy with photon as the quantum unit.Microphotonics employs at least two different materials with a large differential index of refraction to squeeze the light down to a small size. Generally speaking, virtually all of microphotonics relies on Fresnel reflection to guide the light. If the photons reside mainly in the higher index material, the confinement is due to total internal reflection. If the confinement is due many distributed Fresnel reflections, the device is termed a photonic crystal. There are many different types of geometries used in microphotonics including optical waveguides, optical microcavities, and Arrayed waveguide gratings.

Microphysics

The term microphysics refers to areas of physics that study phenomena that take place on the microscopic scale (length scales smaller than 1 mm), such as:

Atomic physics

Cloud physics

Mesoscopic physics

Molecular physics

Nanotechnology

Nuclear physics

Particle physics

Plasma physics

Quantum mechanics

String theory

MountainsMap

Mountains is an image analysis and surface metrology software platform published by the company Digital Surf. Its core is micro-topography, the science of studying surface texture and form in 3D at the microscopic scale. The software is dedicated to profilometers, 3D light microscopes ("MountainsMap"), scanning electron microscopes ("MountainsSEM") and scanning probe microscopes ("MountainsSPIP").

Optical force

The optical force is a phenomenon whereby beams of light can attract and repel each other. The force acts along an axis which is perpendicular to the light beams. Because of this, parallel beams can be induced to converge or diverge. The optical force works on a microscopic scale, and cannot currently be detected at larger scales. It was discovered by a team of Yale researchers led by electrical engineer Hong Tang.

Phased-array optics

Phased array optics is the technology of controlling the phase and amplitude of light waves transmitting, reflecting, or captured (received) by a two-dimensional surface using adjustable surface elements. A optical phased array (OPA) is the optical analog of a radio wave phased array. By dynamically controlling the optical properties of a surface on a microscopic scale, it is possible to steer the direction of light beams (in an OPA transmitter), or the view direction of sensors (in an OPA receiver), without any moving parts. Phased array beam steering is used for optical switching and multiplexing in optoelectronic devices, and for aiming laser beams on a macroscopic scale.

Complicated patterns of phase variation can be used to produce diffractive optical elements, such as dynamic virtual lenses, for beam focusing or splitting in addition to aiming. Dynamic phase variation can also produce real-time holograms. Devices permitting detailed addressable phase control over two dimensions are a type of spatial light modulator (SLM).

Quasi-solid

Falsely-solid, or, semisolid is the physical term for something whose state lies between a solid and a liquid. While similar to solids in some respects, such as having the ability to support their own weight and hold their shapes, a quasi-solid also shares some properties of liquids, such as conforming in shape to something applying pressure to it and the ability to flow under pressure. The words quasi-solid, semisolid, and semiliquid may be used interchangeably.

Quasi-solids and semisolids are also known as amorphous solids because at the microscopic scale they have a disordered structure unlike the more common crystalline solids.

Selective leaching

Selective leaching, also called dealloying, demetalification, parting and selective corrosion, is a corrosion type in some solid solution alloys, when in suitable conditions a component of the alloys is preferentially leached from the material. The less noble metal is removed from the alloy by a microscopic-scale galvanic corrosion mechanism. The most susceptible alloys are the ones containing metals with high distance between each other in the galvanic series, e.g. copper and zinc in brass. The elements most typically undergoing selective removal are zinc, aluminium, iron, cobalt, chromium, and others.

Sensor

In the broadest definition, a sensor is a device, module, or subsystem whose purpose is to detect events or changes in its environment and send the information to other electronics, frequently a computer processor. A sensor is always used with other electronics.

Sensors are used in everyday objects such as touch-sensitive elevator buttons (tactile sensor) and lamps which dim or brighten by touching the base, besides innumerable applications of which most people are never aware. With advances in micromachinery and easy-to-use microcontroller platforms, the uses of sensors have expanded beyond the traditional fields of temperature, pressure or flow measurement, for example into MARG sensors. Moreover, analog sensors such as potentiometers and force-sensing resistors are still widely used. Applications include manufacturing and machinery, airplanes and aerospace, cars, medicine, robotics and many other aspects of our day-to-day life.

A sensor's sensitivity indicates how much the sensor's output changes when the input quantity being measured changes. For instance, if the mercury in a thermometer moves 1 cm when the temperature changes by 1 °C, the sensitivity is 1 cm/°C (it is basically the slope Dy/Dx assuming a linear characteristic). Some sensors can also affect what they measure; for instance, a room temperature thermometer inserted into a hot cup of liquid cools the liquid while the liquid heats the thermometer. Sensors are usually designed to have a small effect on what is measured; making the sensor smaller often improves this and may introduce other advantages. Technological progress allows more and more sensors to be manufactured on a microscopic scale as microsensors using MEMS technology. In most cases, a microsensor reaches a significantly higher speed and sensitivity compared with macroscopic approaches.

Texture (geology)

Texture (or rock microstructure) in geology refers to the relationship between the materials of which a rock is composed. The broadest textural classes are crystalline (in which the components are intergrown and interlocking crystals), fragmental (in which there is an accumulation of fragments by some physical process), aphanitic (in which crystals are not visible to the unaided eye), and glassy (in which the particles are too small to be seen and amorphously arranged). The geometric aspects and relations amongst the component particles or crystals are referred to as the crystallographic texture or preferred orientation. Textures can be quantified in many ways. The most common parameter is the crystal size distribution. This creates the physical appearance or character of a rock, such as grain size, shape, arrangement, and other properties, at both the visible and microscopic scale.

Crystalline textures include phaneritic, foliated, and porphyritic. Phaneritic textures are where interlocking crystals of igneous rock are visible to the unaided eye. Foliated texture is where metamorphic rock is made of layers of materials. Porphyritic texture is one in which larger pieces (phenocrysts) are embedded in a background mass made of much finer grains.Fragmental textures include clastic, bioclastic, and pyroclastic.A preferred mineral orientation, is the texture of metamorphic rock in which its grains have a flattened shape (inequant), and their planes tend to be oriented in the same direction.

Wenlock Series Lagerstätte

The Silurian Lagerstätte preserved in the limestone Wenlock Series of Herefordshire, England, offers paleontologists a rare snapshot of a moment in time, about 420 Mya. In the formation, layers of fine-grained volcanic ash punctuate a sequence of carbonate muds that were accumulating in a marine environment on the outer continental shelf. In this fine-grained matrix, soft-bodied animals and delicate, lightly sclerotized chitinous shells are often preserved in three dimensions, as calcitic fossilizations within calcareous nodules. Calcitic fossilization is an unusual feature.

The lagerstätte, discovered and first published in 1996, provides a wider representation of organisms than conventional fossilizations of shelly and bony elements. The Wenlock Series offers a diverse macrofauna that includes polychaete worms (Kenostrychus), sponges, graptolites, starfish, a chelicerate (Offacolus), a stem-group mandibulate (Aquilonifer) and a vermiform mollusc (Acaenoplax). On the microscopic scale the diverse microfauna includes abundant well-preserved radiolarians.

The delicate Wenlock fossils are difficult to separate from split sections, so Mark Sutton and his team have devised a method of serially grinding sections; from digital photographs three-dimensional "digital fossils" are reconstructed from datasets.