1.
Ice crystals
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Ice crystals are solid ice exhibiting atomic ordering on various length scales and include hexagonal columns, hexagonal plates, dendritic crystals, and diamond dust. The hugely symmetric shapes are due to growth, namely. Depending on environmental temperature and humidity, ice crystals can develop from the hexagonal prism into numerous symmetric shapes. Possible shapes for ice crystals are columns, needles, plates and dendrites, if the crystal migrates into regions with different environmental conditions, the growth pattern may change, and the final crystal may show mixed patterns. Ice crystals tend to fall with their major axis aligned along the horizontal, electrification of ice crystals can induce alignments different from the horizontal. Electrified ice crystals are also detectable by polarimetric weather radars. Temperature and humidity determine many different crystalline forms, Ice crystals are responsible for various atmospheric optics displays. Ice clouds are composed of ice crystals, the most notable being cirrus clouds, at ambient temperature and pressure, water molecules have a V shape. The two hydrogen bond to the oxygen atom at a 105° angle. Common ice crystals are symmetrical and have a hexagonal pattern, square ice crystals form at room temperature when squeezed between two layers of graphene. The material is a new phase of ice, joining 17 others. The research derived from the discovery that water vapor and liquid water could pass through laminated sheets of graphene oxide. The effect is thought to be driven by the van der Waals force, snow Ice spike Diamond dust Needle ice Ice lens SnowCrystals. com. At Caltech American Meteorological Society Glossary
2.
Snow
–
Snowstorms organize and develop by feeding on sources of atmospheric moisture and cold air. Snowflakes nucleate around particles in the atmosphere by attracting supercooled water droplets, snowflakes take on a variety of shapes, basic among these are platelets, needles, columns and rime. As snow accumulates into a snowpack, it may blow into drifts, over time, accumulated snow metamorphoses, by sintering, sublimation and freeze-thaw. Where the climate is cold enough for year-to-year accumulation, a glacier may form, otherwise, snow typically melts seasonally, causing runoff into streams and rivers and recharging groundwater. Major snow-prone areas include the regions, the upper half of the Northern Hemisphere and mountainous regions worldwide with sufficient moisture. In the Southern Hemisphere, snow is confined primarily to mountainous areas, Snow affects ecosystems, as well, by providing an insulating layer during winter under which plants and animals are able to survive the cold. Snow develops in clouds that themselves are part of a weather system. The physics of snow crystal development in clouds results from a set of variables that include moisture content. The resulting shapes of the falling and fallen crystals can be classified into a number of shapes and combinations. Occasionally, some plate-like, dendritic and stellar-shaped snowflakes can form under clear sky with a cold temperature inversion present. Two additional and locally productive sources of snow are lake-effect storms and elevation effects, miid-latitude cyclones are low pressure areas which are capable of producing anything from cloudiness and mild snow storms to heavy blizzards. During a hemispheres fall, winter, and spring, the atmosphere over continents can be cold enough through the depth of the troposphere to cause snowfall, in the Northern Hemisphere, the northern side of the low pressure area produces the most snow. For the southern mid-latitudes, the side of a cyclone that produces the most snow is the southern side, a cold front, the leading edge of a cooler mass of air, can produce frontal snowsqualls—an intense frontal convective line, when temperature is near freezing at the surface. The strong convection that develops has enough moisture to produce whiteout conditions at places which line passes over as the wind causes intense blowing snow. This type of snowsquall generally lasts less than 30 minutes at any point along its path, in cases where there is a large amount of vertical growth and mixing the squall may develop embedded cumulonimbus clouds resulting in lightning and thunder which is dubbed thundersnow. A warm front can produce snow for a period, as warm, moist air overrides below-freezing air, often, snow transitions to rain in the warm sector behind the front. The same effect occurs over bodies of salt water, when it is termed ocean-effect or bay-effect snow. The effect is enhanced when the air mass is uplifted by the orographic influence of higher elevations on the downwind shores
3.
Supersaturation
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Supersaturation is a state of a solution that contains more of the dissolved material than could be dissolved by the solvent under normal circumstances. It can also refer to a vapor of a compound that has a higher pressure than the pressure of that compound. Special conditions need to be met in order to generate a supersaturated solution, one of the easiest ways to do this relies on the temperature dependence of solubility. As a general rule, the heat is added to a system. Therefore, at high temperatures, more solute can be dissolved than at room temperature, the precipitation or crystallization of the solute takes longer than the actual cooling time because the molecules need to meet up and form the precipitate without being knocked apart by water. Thus, the larger the molecule, the longer it will take to crystallize due to the principles of Brownian motion, the condition of supersaturation does not necessarily have to be reached through the manipulation of heat. The ideal gas law suggests that pressure and volume can also be changed to force a system into a supersaturated state, if the volume of solvent is decreased, the concentration of the solute can be above the saturation point and thus create a supersaturated solution. The decrease in volume is most commonly generated through evaporation, similarly, an increase in pressure can drive a solution to a supersaturated state. All three of these rely on the fact that the conditions of the solution can be changed quicker than the solute can precipitate or crystallize out. Supersaturated solutions will also undergo crystallization under specific conditions, in a normal solution, once the maximum amount of solute is dissolved, adding more solute would either cause the dissolved solute to precipitate out and/or for the solute to not dissolve at all. Similarly, there are cases wherein solubility of a solution is decreased by manipulating temperature, pressure, or volume. In these cases, the solute will simply precipitate out and this is due to the fact that a supersaturated solution is in a higher energy state than a saturated solution. Crystallization will occur to allow the solution to reach an energy state. The activation energy comes in the form of a crystal being added to the liquid solution. This nuclei can be added from another source, which is known as seeding, or can spontaneously form within the solution due partly to ion. This process is known as primary nucleation and it is necessary for the nuclei to be identical to the solute that is crystallizing. This will allow for the ions to build up on the nuclei. There are a multitude of factors that affect the rate and order of magnitude with which crystallization proceeds as well as the difference in formation of crystallites
4.
Supercooling
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Supercooling, also known as undercooling, is the process of lowering the temperature of a liquid or a gas below its freezing point without it becoming a solid. A liquid crossing its standard freezing point will crystalize in the presence of a crystal or nucleus around which a crystal structure can form creating a solid. Lacking any such nuclei, the phase can be maintained all the way down to the temperature at which crystal homogeneous nucleation occurs. Homogeneous nucleation can occur above the transition temperature, but if homogeneous nucleation has not occurred above that temperature. Water normally freezes at 273.15 K, but it can be supercooled at standard pressure down to its homogeneous nucleation at almost 224.8 K. If water is cooled at a rate on the order of 106 K/s, the crystal nucleation can be avoided and water becomes a glass — that is and its glass transition temperature is much colder and harder to determine, but studies estimate it at about 136 K. Glassy water can be heated up to approximately 150 K without nucleation occurring, in the range of temperatures between 231 K and 150 K, experiments find only crystal ice. Droplets of supercooled water often exist in stratiform and cumulus clouds, Freezing rain is also caused by supercooled droplets. The process opposite to supercooling, the melting of a solid above the point, is much more difficult. It is possible, at a pressure, to superheat a liquid above its boiling point without it becoming gaseous. Supercooling is often confused with freezing-point depression, supercooling is the cooling of a liquid below its freezing point without it becoming solid. Constitutional supercooling, which occurs during solidification, is due to compositional solid changes, when solidifying a liquid, the interface is often unstable, and the velocity of the solid–liquid interface must be small in order to avoid constitutional supercooling. Supercooled zones are observed when the temperature gradient at the interface is larger than the temperature gradient. Therefore, the thermal gradient necessary to create a stable solid front is as expressed below. ∂ T ∂ x < m C0 v k D For more information, the authors are confusing supercooling with freezing-point depression. The paragraphs above warn about this confusion, in order to survive extreme low temperatures in certain environments, some animals undergo forms of supercooling that allow them to remain unfrozen and avoid cell damage and death. The winter flounder is one fish that utilizes these proteins to survive in its frigid environment. Noncolligative proteins are secreted by the liver into the bloodstream, other animals use colligative antifreezes, which increases the concentration of solutes in their bodily fluids, thus lowering their freezing point
5.
Freezing
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Freezing, or solidification, is a phase transition in which a liquid turns into a solid when its temperature is lowered below its freezing point. For most substances, the melting and freezing points are the temperature, however. For example, agar displays a hysteresis in its melting point and it melts at 85 °C and solidifies from 32 °C to 40 °C. Most liquids freeze by crystallization, formation of crystalline solid from the uniform liquid, because of the latent heat of fusion, the freezing is greatly slowed down and the temperature will not drop anymore once the freezing starts but will continue dropping once it finishes. Crystallization consists of two events, nucleation and crystal growth. Nucleation is the step wherein the molecules start to gather into clusters, on the scale, arranging in a defined. The crystal growth is the subsequent growth of the nuclei that succeed in achieving the critical cluster size, in spite of the second law of thermodynamics, crystallization of pure liquids usually begins at a lower temperature than the melting point, due to high activation energy of homogeneous nucleation. The creation of a nucleus implies the formation of an interface at the boundaries of the new phase, some energy is expended to form this interface, based on the surface energy of each phase. If a hypothetical nucleus is too small, the energy that would be released by forming its volume is not enough to create its surface, Freezing does not start until the temperature is low enough to provide enough energy to form stable nuclei. Under high pressure water will super cool to as low as −70 °C before freezing, Freezing is almost always an exothermic process, meaning that as liquid changes into solid, heat and pressure is released. This is often seen as counter-intuitive, since the temperature of the material does not rise during freezing, but this can be understood, since heat must be continually removed from the freezing liquid or the freezing process will stop. The energy released upon freezing is a latent heat, and is known as the enthalpy of fusion and is exactly the same as the required to melt the same amount of the solid. Low-temperature helium is the only exception to the general rule. Helium-3 has an enthalpy of fusion at temperatures below 0.3 K. Helium-4 also has a very slightly negative enthalpy of fusion below 0.8 K. This means that, at appropriate constant pressures, heat must be added to these substances in order to freeze them, certain materials, such as glass and glycerol, may harden without crystallizing, these are called amorphous solids. Amorphous materials as well as some polymers do not have a freezing point, instead, there is a gradual change in their viscoelastic properties over a range of temperatures. Such materials are characterized by a transition that occurs at a glass transition temperature. Because vitrification is a process, it does not qualify as freezing
6.
Emergence
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Emergence is central in theories of integrative levels and of complex systems. For instance, the phenomenon of life as studied in biology is an emergent property of chemistry, in philosophy, theories that emphasize emergent properties have been called emergentism. Almost all accounts of emergentism include a form of epistemic or ontological irreducibility to the lower levels, in philosophy, emergence is often understood to be a claim about the etiology of a systems properties. An emergent property of a system, in context, is one that is not a property of any component of that system. Nicolai Hartmann, one of the first modern philosophers to write on emergence and this idea of emergence has been around since at least the time of Aristotle. John Stuart Mill and Julian Huxley are two of many scientists and philosophers who have written on the concept, further, every resultant is clearly traceable in its components, because these are homogeneous and commensurable. The emergent is unlike its components insofar as these are incommensurable, economist Jeffrey Goldstein provided a current definition of emergence in the journal Emergence. Goldstein initially defined emergence as, the arising of novel and coherent structures, patterns, Systems scientist Peter Corning also says that living systems cannot be reduced to underlying laws of physics, Rules, or laws, have no causal efficacy, they do not in fact “generate” anything. They serve merely to describe regularities and consistent relationships in nature and these patterns may be very illuminating and important, but the underlying causal agencies must be separately specified. But that aside, the game of chess illustrates, why any laws or rules of emergence and evolution are insufficient. Even in a game, you cannot use the rules to predict “history” – i. e. the course of any given game. Indeed, you cannot even reliably predict the move in a chess game. Because the “system” involves more than the rules of the game and it also includes the players and their unfolding, moment-by-moment decisions among a very large number of available options at each choice point. The game of chess is inescapably historical, even though it is constrained and shaped by a set of rules. Moreover, and this is a key point, the game of chess is also shaped by teleonomic, cybernetic and it is not simply a self-ordered process, it involves an organized, “purposeful” activity. Usage of the notion emergence may generally be subdivided into two perspectives, that of weak emergence and strong emergence, in terms of physical systems, weak emergence is a type of emergence in which the emergent property is amenable to computer simulation. This is opposed to the notion of strong emergence, in which the emergent property cannot be simulated by a computer. Some common points between the two notions are that emergence concerns new properties produced as the system grows, which is to say ones which are not shared with its components or prior states, also, it is assumed that the properties are supervenient rather than metaphysically primitive
7.
Diffuse reflection
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Diffuse reflection is the reflection of light from a surface such that an incident ray is reflected at many angles rather than at just one angle as in the case of specular reflection. An illuminated ideal diffuse reflecting surface will have equal luminance from all directions which lie in the adjacent to the surface. A surface built from a non-absorbing powder such as plaster, or from such as paper, or from a polycrystalline material such as white marble. Many common materials exhibit a mixture of specular and diffuse reflection, the visibility of objects, excluding light-emitting ones, is primarily caused by diffuse reflection of light, it is diffusely-scattered light that forms the image of the object in the observers eye. Diffuse reflection from solids is not due to surface roughness. A flat surface is indeed required to give specular reflection, a piece of highly polished white marble remains white, no amount of polishing will turn it into a mirror. Polishing produces some specular reflection, but the light continues to be diffusely reflected. All these rays walk through the snow crystallytes, which do not absorb light, until they arrive at the surface, the result is that the light that was sent out is returned in all directions, so that snow is white despite being made of transparent material. This mechanism is very general, because almost all materials are made of small things held together. Mineral materials are polycrystalline, one can describe them as made of a 3D mosaic of small. Organic materials are composed of fibers or cells, with their membranes. And each interface, inhomogeneity or imperfection can deviate, reflect or scatter light, virtually all materials can give specular reflection, provided that their surface can be polished to eliminate irregularities comparable with light wavelength. Diffuse reflection from white materials, instead, can be efficient in giving back all the light they receive. Up to this point white objects have been discussed, which do not absorb light, but the above scheme continues to be valid in the case that the material is absorbent. In this case, diffused rays will lose some wavelengths during their walk in the material, diffusion affects the color of objects in a substantial manner because it determines the average path of light in the material, and hence to which extent the various wavelengths are absorbed. Red ink looks black when it stays in its bottle and its vivid color is only perceived when it is placed on a scattering material. This is so because lights path through the fibers is only a fraction of millimeter long. However, light from the bottle has crossed several centimeters of ink and has been heavily absorbed, and, when a colored object has both diffuse and specular reflection, usually only the diffuse component is colored
8.
Spectrum
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A spectrum is a condition that is not limited to a specific set of values but can vary, without steps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors in visible light after passing through a prism, as scientific understanding of light advanced, it came to apply to the entire electromagnetic spectrum. Spectrum has since been applied by analogy to topics outside of optics, thus, one might talk about the spectrum of political opinion, or the spectrum of activity of a drug, or the autism spectrum. In these uses, values within a spectrum may not be associated with precisely quantifiable numbers or definitions, such uses imply a broad range of conditions or behaviors grouped together and studied under a single title for ease of discussion. Nonscientific uses of the spectrum are sometimes misleading. For instance, a single left–right spectrum of opinion does not capture the full range of peoples political beliefs. Political scientists use a variety of biaxial and multiaxial systems to accurately characterize political opinion. In most modern usages of spectrum there is a theme between the extremes at either end. This was not always true in older usage, in Latin spectrum means image or apparition, including the meaning spectre. Spectral evidence is testimony about what was done by spectres of persons not present physically and it was used to convict a number of persons of witchcraft at Salem, Massachusetts in the late 17th century. The word spectrum was used to designate a ghostly optical afterimage by Goethe in his Theory of Colors and Schopenhauer in On Vision. The prefix spectro- is used to form words relating to spectra, for example, a spectrometer is a device used to record spectra and spectroscopy is the use of a spectrometer for chemical analysis. In the 17th century the word spectrum was introduced into optics by Isaac Newton, soon the term referred to a plot of light intensity or power as a function of frequency or wavelength, also known as a spectral density plot. The term spectrum was expanded to apply to other waves, such as sound waves that could also be measured as a function of frequency, frequency spectrum and power spectrum of a signal. The term now applies to any signal that can be measured or decomposed along a variable such as energy in electron spectroscopy or mass to charge ratio in mass spectrometry. Spectrum is also used to refer to a representation of the signal as a function of the dependent variable. Devices used to measure an electromagnetic spectrum are called spectrograph or spectrometer, the visible spectrum is the part of the electromagnetic spectrum that can be seen by the human eye. The wavelength of light ranges from 390 to 700 nm
9.
Light
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Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum. The word usually refers to light, which is visible to the human eye and is responsible for the sense of sight. Visible light is defined as having wavelengths in the range of 400–700 nanometres, or 4.00 × 10−7 to 7.00 × 10−7 m. This wavelength means a range of roughly 430–750 terahertz. The main source of light on Earth is the Sun, sunlight provides the energy that green plants use to create sugars mostly in the form of starches, which release energy into the living things that digest them. This process of photosynthesis provides virtually all the used by living things. Historically, another important source of light for humans has been fire, with the development of electric lights and power systems, electric lighting has effectively replaced firelight. Some species of animals generate their own light, a process called bioluminescence, for example, fireflies use light to locate mates, and vampire squids use it to hide themselves from prey. Visible light, as all types of electromagnetic radiation, is experimentally found to always move at this speed in a vacuum. In physics, the term sometimes refers to electromagnetic radiation of any wavelength. In this sense, gamma rays, X-rays, microwaves and radio waves are also light, like all types of light, visible light is emitted and absorbed in tiny packets called photons and exhibits properties of both waves and particles. This property is referred to as the wave–particle duality, the study of light, known as optics, is an important research area in modern physics. Generally, EM radiation, or EMR, is classified by wavelength into radio, microwave, infrared, the behavior of EMR depends on its wavelength. Higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths, when EMR interacts with single atoms and molecules, its behavior depends on the amount of energy per quantum it carries. There exist animals that are sensitive to various types of infrared, infrared sensing in snakes depends on a kind of natural thermal imaging, in which tiny packets of cellular water are raised in temperature by the infrared radiation. EMR in this range causes molecular vibration and heating effects, which is how these animals detect it, above the range of visible light, ultraviolet light becomes invisible to humans, mostly because it is absorbed by the cornea below 360 nanometers and the internal lens below 400. Furthermore, the rods and cones located in the retina of the eye cannot detect the very short ultraviolet wavelengths and are in fact damaged by ultraviolet. Many animals with eyes that do not require lenses are able to detect ultraviolet, by quantum photon-absorption mechanisms, various sources define visible light as narrowly as 420 to 680 to as broadly as 380 to 800 nm
10.
Snow science
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Snowstorms organize and develop by feeding on sources of atmospheric moisture and cold air. Snowflakes nucleate around particles in the atmosphere by attracting supercooled water droplets, snowflakes take on a variety of shapes, basic among these are platelets, needles, columns and rime. As snow accumulates into a snowpack, it may blow into drifts, over time, accumulated snow metamorphoses, by sintering, sublimation and freeze-thaw. Where the climate is cold enough for year-to-year accumulation, a glacier may form, otherwise, snow typically melts seasonally, causing runoff into streams and rivers and recharging groundwater. Major snow-prone areas include the regions, the upper half of the Northern Hemisphere and mountainous regions worldwide with sufficient moisture. In the Southern Hemisphere, snow is confined primarily to mountainous areas, Snow affects ecosystems, as well, by providing an insulating layer during winter under which plants and animals are able to survive the cold. Snow develops in clouds that themselves are part of a weather system. The physics of snow crystal development in clouds results from a set of variables that include moisture content. The resulting shapes of the falling and fallen crystals can be classified into a number of shapes and combinations. Occasionally, some plate-like, dendritic and stellar-shaped snowflakes can form under clear sky with a cold temperature inversion present. Two additional and locally productive sources of snow are lake-effect storms and elevation effects, miid-latitude cyclones are low pressure areas which are capable of producing anything from cloudiness and mild snow storms to heavy blizzards. During a hemispheres fall, winter, and spring, the atmosphere over continents can be cold enough through the depth of the troposphere to cause snowfall, in the Northern Hemisphere, the northern side of the low pressure area produces the most snow. For the southern mid-latitudes, the side of a cyclone that produces the most snow is the southern side, a cold front, the leading edge of a cooler mass of air, can produce frontal snowsqualls—an intense frontal convective line, when temperature is near freezing at the surface. The strong convection that develops has enough moisture to produce whiteout conditions at places which line passes over as the wind causes intense blowing snow. This type of snowsquall generally lasts less than 30 minutes at any point along its path, in cases where there is a large amount of vertical growth and mixing the squall may develop embedded cumulonimbus clouds resulting in lightning and thunder which is dubbed thundersnow. A warm front can produce snow for a period, as warm, moist air overrides below-freezing air, often, snow transitions to rain in the warm sector behind the front. The same effect occurs over bodies of salt water, when it is termed ocean-effect or bay-effect snow. The effect is enhanced when the air mass is uplifted by the orographic influence of higher elevations on the downwind shores
11.
Ice
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Ice is water frozen into a solid state. Depending on the presence of such as particles of soil or bubbles of air. In the Solar System, ice is abundant and occurs naturally from as close to the Sun as Mercury to as far as away the Oort cloud objects, beyond the Solar System, it occurs as interstellar ice. It falls as snowflakes and hail or occurs as frost, icicles or ice spikes, Ice molecules can exhibit up to sixteen different phases that depend on temperature and pressure. When water is cooled rapidly, up to three different types of ice can form depending on the history of its pressure and temperature. When cooled slowly correlated proton tunneling occurs below 20 K giving rise to macroscopic quantum phenomena, virtually all the ice on Earths surface and in its atmosphere is of a hexagonal crystalline structure denoted as ice Ih with minute traces of cubic ice denoted as ice Ic. The most common phase transition to ice Ih occurs when water is cooled below 0°C at standard atmospheric pressure. It may also be deposited directly by water vapor, as happens in the formation of frost, the transition from ice to water is melting and from ice directly to water vapor is sublimation. Ice is used in a variety of ways, including cooling, winter sports, as a naturally occurring crystalline inorganic solid with an ordered structure, ice is considered a mineral. It possesses a regular crystalline structure based on the molecule of water, an unusual property of ice frozen at atmospheric pressure is that the solid is approximately 8. 3% less dense than liquid water. The density of ice is 0.9167 g/cm3 at 0 °C, liquid water is densest, essentially 1.00 g/cm³, at 4 °C and becomes less dense as the water molecules begin to form the hexagonal crystals of ice as the freezing point is reached. This is due to hydrogen bonding dominating the intermolecular forces, which results in a packing of molecules less compact in the solid, density of ice increases slightly with decreasing temperature and has a value of 0.9340 g/cm³ at −180 °C. When water freezes, it increases in volume and it is also a common cause of the flooding of houses when water pipes burst due to the pressure of expanding water when it freezes. The result of this process is that ice floats on liquid water, sufficiently thin ice sheets allow light to pass through while protecting the underside from short-term weather extremes such as wind chill. This creates an environment for bacterial and algal colonies. When ice melts, it absorbs as much energy as it would take to heat an equivalent mass of water by 80 °C, during the melting process, the temperature remains constant at 0 °C. While melting, any energy added breaks the bonds between ice molecules. Energy becomes available to increase the thermal energy only after enough hydrogen bonds are broken that the ice can be considered liquid water, the amount of energy consumed in breaking hydrogen bonds in the transition from ice to water is known as the heat of fusion
12.
Silver iodide
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Silver iodide is an inorganic compound with the formula AgI. The compound is a yellow solid, but samples almost always contain impurities of metallic silver that give a gray coloration. The silver contamination arises because AgI is highly photosensitive and this property is exploited in silver-based photography. Silver iodide is used as an antiseptic and in cloud seeding. The structure adopted by silver iodide is temperature dependent, Below 420 K and this phase is encountered in nature as the mineral iodargyrite. Above 420 K, the α-phase becomes more stable and this motif is a body-centered cubic structure which has the silver centers distributed randomly between 6 octahedral,12 tetrahedral and 24 trigonal sites. At this temperature, Ag+ ions can move rapidly through the solid, the transition between the β and α forms represents the melting of the silver sublattice. The entropy of fusion for α-AgI is approximately half that for sodium chloride and this can be rationalized by considering the AgI crystalline lattice to have already partly melted in the transition between α and β polymorphs. A metastable γ-phase also exists below 420 K with the zinc blende structure, silver iodide is prepared by reaction of an iodide solution with a solution of silver ions. The solid is a mixture of the two principal phases, dissolution of the AgI in hydroiodic acid, followed by dilution with water precipitates β-AgI. Alternatively, dissolution of AgI in a solution of concentrated silver nitrate followed by dilution affords α-AgI, if the preparation is not conducted in the absence of sunlight, the solid darkens rapidly, the light causing the reduction of ionic silver to metallic. The photosensitivity varies with sample purity, the crystalline structure of β-AgI is similar to that of ice, allowing it to induce freezing by the process known as heterogeneous nucleation. Approximately 50,000 kg are used for cloud seeding annually, extreme exposure can lead to argyria, characterized by localized discoloration of body tissue
13.
Dry ice
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Dry ice, sometimes referred to as cardice, is the solid form of carbon dioxide. It is used primarily as a cooling agent and its advantages include lower temperature than that of water ice and not leaving any residue. It is useful for preserving frozen foods where mechanical cooling is unavailable, Dry ice sublimates at −78.5 °C at Earth atmospheric pressures. This extreme cold makes the solid dangerous to handle without protection due to burns caused by freezing, while generally not very toxic, the outgassing from it can cause hypercapnia due to buildup in confined locations. Dry ice is the form of carbon dioxide, a molecule consisting of a single carbon atom bonded to two oxygen atoms. Dry ice is colorless, non-flammable, with a sour zesty odor, at pressures below 5.13 atm and temperatures below −56.4 °C, CO2 changes from a solid to a gas with no intervening liquid form, through a process called sublimation. The opposite process is called deposition, where CO2 changes from the gas to solid phase, at atmospheric pressure, sublimation/deposition occurs at −78.5 °C. The density of dry ice varies, but usually ranges between about 1.4 and 1.6 g/cm3. The low temperature and direct sublimation to a gas makes dry ice an effective coolant, since it is colder than water ice and its enthalpy of sublimation is 571 kJ/kg. Dry ice is non-polar, with a moment of zero. The composition results in low thermal and electrical conductivity and it is generally accepted that dry ice was first observed in 1835 by French inventor Adrien-Jean-Pierre Thilorier, who published the first account of the substance. In his experiments, he noted that when opening the lid of a cylinder containing liquid carbon dioxide. This left only solid dry ice in the container, slate applied for a US patent to sell dry ice commercially. Subsequently, he became the first to make dry ice successful as an industry, in 1925, this solid form of CO2 was trademarked by the DryIce Corporation of America as Dry ice, thus leading to its common name. That same year the DryIce Co. sold the substance commercially for the first time, the alternative name Cardice is a registered trademark of Air Liquide UK Ltd. It is sometimes written as card ice, First, gases with a high concentration of carbon dioxide are produced. Such gases can be a byproduct of another process, such as producing ammonia from nitrogen and natural gas, second, the carbon dioxide-rich gas is pressurized and refrigerated until it liquifies. When this occurs some liquid carbon dioxide vaporizes, causing a lowering of temperature of the remaining liquid
14.
Cloud seeding
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The usual intent is to increase precipitation, but hail and fog suppression are also widely practiced in airports. Cloud seeding also occurs due to ice nucleators in nature, most of which are bacterial in origin, the most common chemicals used for cloud seeding include silver iodide, potassium iodide and dry ice. Liquid propane, which expands into a gas, has also been used and this can produce ice crystals at higher temperatures than silver iodide. After promising research, the use of materials, such as table salt, is becoming more popular. When Cloud seeding increases snowfall takes place when temperatures within the clouds are between 19 and −4 °F, introduction of a substance such as silver iodide, which has a crystalline structure similar to that of ice, will induce freezing nucleation. In mid-latitude clouds, the usual seeding strategy has been based on the fact that the vapor pressure is lower over ice than over water. The formation of ice particles in super cooled clouds allows those particles to grow at the expense of liquid droplets, if sufficient growth takes place, the particles become heavy enough to fall as precipitation from clouds that otherwise would produce no precipitation. This process is known as static seeding, Seeding of warm-season or tropical cumulonimbus clouds seeks to exploit the latent heat released by freezing. Cloud seeding chemicals may be dispersed by aircraft or by dispersion devices located on the ground, for release by aircraft, silver iodide flares are ignited and dispersed as an aircraft flies through the inflow of a cloud. When released by devices on the ground, the particles are carried downwind. An electronic mechanism was tested in 2010, when infrared laser pulses were directed to the air above Berlin by researchers from the University of Geneva, the experimenters posited that the pulses would encourage atmospheric sulfur dioxide and nitrogen dioxide to form particles that would then act as seeds. Cloud seeding has never been proven to work. Claims are made that new technology and research has produced results that make cloud seeding a dependable and affordable water supply practice for many regions. But while practiced widely around the world, the effectiveness of cloud seeding is still a matter of academic debate, in 2003 the US National Research Council released a report stating. science is unable to say with assurance which, if any, seeding techniques produce positive effects. In the 55 years following the first cloud-seeding demonstrations, substantial progress has made in understanding the natural processes that account for our daily weather. Yet scientifically acceptable proof for significant seeding effects has not been achieved, referring to 1903,1915,1919,1944, and 1947 weather modification experiments, the Australian Federation of Meteorology discounted rain making. By the 1950s, the CSIRO Division of Radiophysics switched to investigating the physics of clouds and had hoped by 1957 to better understand these processes. By the 1960s, the dreams of making had faded only to be re-ignited post-corporatisation of the Snowy Mountains Scheme in order to achieve above target water
15.
Scanning electron microscope
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A scanning electron microscope is a type of electron microscope that produces images of a sample by scanning it with a focused beam of electrons. The electrons interact with atoms in the sample, producing various signals that contain information about the surface topography. The electron beam is scanned in a raster scan pattern. SEM can achieve better than 1 nanometer. Specimens can be observed in vacuum, in low vacuum, in wet conditions. The most common SEM mode is detection of electrons emitted by atoms excited by the electron beam. The number of electrons that can be detected depends, among other things. By scanning the sample and collecting the electrons that are emitted using a special detector. An account of the history of SEM has been presented by McMullan. Ardenne applied the principle not only to achieve magnification but also to purposefully eliminate the chromatic aberration otherwise inherent in the electron microscope. He further discussed the various modes, possibilities and theory of SEM. The types of produced by an SEM include secondary electrons, reflected or back-scattered electrons, photons of characteristic X-rays and light, absorbed current. Secondary electron detectors are standard equipment in all SEMs, but it is rare that a machine would have detectors for all other possible signals. The signals result from interactions of the beam with atoms at various depths within the sample. In the most common or standard detection mode, ie secondary electron imaging or SEI, consequently, SEM can produce very high-resolution images of a sample surface, revealing details less than 1 nm in size. Back-scattered electrons are beam electrons that are reflected from the sample by elastic scattering and they emerge from deeper locations within the specimen and consequently the resolution of BSE images is generally poorer than SE images. BSE images can provide information about the distribution of different elements in the sample, characteristic X-rays are emitted when the electron beam removes an inner shell electron from the sample, causing a higher-energy electron to fill the shell and release energy. These characteristic X-rays are used to identify the composition and measure the abundance of elements in the sample, due to the very narrow electron beam, SEM micrographs have a large depth of field yielding a characteristic three-dimensional appearance useful for understanding the surface structure of a sample
16.
Hard rime
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Hard rime is a white ice that forms when the water droplets in fog freeze to the outer surfaces of objects. It is often seen on trees atop mountains and ridges in winter and this fog freezes to the windward side of tree branches, buildings, or any other solid objects, usually with high wind velocities and air temperatures between −2 and −8 °C. Hard rime formations are difficult to shake off, they have an appearance, unlike soft rime, which looks feathery or spiky, or clear ice. Rime ice can accumulate on the edges and control surfaces of aircraft operating in certain meteorological conditions. Rime is also a weather form, meteorologists distinguish between three basic types of ice forming on vertical and horizontal surfaces by deposition of supercooled water droplets. Of course there are also intermediate formations, soft rime is less dense than hard rime and is milky and crystalline, like sugar. Soft rime appears similar to hoar frost, hard rime is somewhat less milky, especially if it is not heavy. Clear ice is transparent and homogeneous and resembles ice-cube ice in appearance and its amorphous, dense structure helps it cling tenaciously to any surface on which it forms. Both rime types are less dense than ice and cling less tenaciously. Glaze ice is similar in appearance to clear ice but it is the result of a different process. These three types occur also when ice forms on the surface of an aircraft when it flies through a cloud made of supercooled water liquid droplets, rime ice is the least dense, milky ice is intermediate and clear ice is the most dense. Dense ice can spoil lift and may have an effect on an airborne aircraft. Under some atmospheric conditions, forming and descending snow crystals may encounter and these droplets, which have a diameter of about 10 µm, can exist in the unfrozen state down to temperatures near −40 °C. Contact between the crystal and the supercooled droplets results in freezing of the liquid droplets onto the surface of the crystals. This process of growth is known as accretion. Crystals that exhibit frozen droplets on their surfaces are referred to as rimed, when this process continues so that the shape of the original snow crystal is no longer identifiable, the resulting crystal is referred to as graupel. However, observations of snow crystals with a scanning electron microscope clearly show cloud droplets measuring up to 50 µm on the surface of the crystals. The rime has been observed on all four forms of snow crystals, including plates, dendrites, columns
17.
Deposition (phase transition)
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Deposition is a thermodynamic process, a phase transition in which gas transforms into solid without passing through the liquid phase. The reverse of deposition is sublimation and hence sometimes deposition is called desublimation, one example of deposition is the process by which, in sub-freezing air, water vapor changes directly to ice without first becoming a liquid. This is how snow forms in clouds, as well as how frost, another example is when frost forms on a leaf. For deposition to occur, thermal energy must be removed from a gas, when the leaf becomes cold enough, water vapor in the air surrounding the leaf loses enough thermal energy to change into a solid. Even though the air temperature may be below the dew point, when the leaf is introduced, the supercooled water vapor immediately begins to condense, but by this point is already past the freezing point. This causes the vapor to change directly into a solid. Another example is the soot that is deposited on the walls of chimneys, soot molecules rise from the fire in a hot and gaseous state. When they come into contact with the walls they cool, and change to the solid state, the process is made use of industrially in combustion chemical vapor deposition. Again, the molecules do not go through a liquid state when going from the gas to the solid. See also physical vapor deposition, which is a class of processes used to thin films of various materials onto various surfaces. Deposition releases energy and is a phase change. Fundamentals of Atmospheric Modeling, Cambridge University Press, 2nd ed.2005, p.525 ISBN 978-0-521-83970-9 Moore, principles of Chemistry, The Molecular Science, Brooks Cole,2009, p.387 ISBN 978-0-495-39079-4 Whitten, Kenneth W. et al. Chemistry, Brooks-Cole, 9th ed.2009, p.7 ISBN 978-0-495-39163-0 Glencoe Science Focus on Physical Science
18.
Micrometer
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Micrometers are usually, but not always, in the form of calipers, which is why micrometer caliper is another common name. The spindle is a very accurately machined screw and the object to be measured is placed between the spindle and the anvil, the spindle is moved by turning the ratchet knob or thimble until the object to be measured is lightly touched by both the spindle and the anvil. Micrometers are also used in telescopes or microscopes to measure the apparent diameter of celestial bodies or microscopic objects, the micrometer used with a telescope was invented about 1638 by William Gascoigne, an English astronomer. Colloquially the word micrometer is often shortened to mike or mic, the word micrometer is a neoclassical coinage from Greek micros, meaning small, and metron, meaning measure. The Merriam-Webster Collegiate Dictionary says that English got it from French, neither the metre nor the micrometre nor the micrometer as we know them today existed at that time. However, the people of that time did have much need for, and interest in, the word was no doubt coined in reference to this endeavor, even if it did not refer specifically to its present-day senses. In 1844 details of Whitworths workshop micrometer were published and this was described as having a strong frame of cast iron, the opposite ends of which were two highly finished steel cylinders, which traversed longitudinally by action of screws. The ends of the cylinders where they met was of hemispherical shape, one screw was fitted with a wheel graduated to measure to the ten thousandth of an inch. His object was to furnish ordinary mechanics with an instrument which, the micrometer caliper was introduced to the mass market in anglophone countries by Brown & Sharpe in 1867, allowing the penetration of the instruments use into the average machine shop. Brown & Sharpe were inspired by earlier devices, one of them being Palmers design. In 1888 Edward W. Morley added to the precision of micrometric measurements, each type of micrometer caliper can be fitted with specialized anvils and spindle tips for particular measuring tasks. For example, the anvil may be shaped in the form of a segment of screw thread, in the form of a v-block, universal micrometer sets come with interchangeable anvils, such as flat, spherical, spline, disk, blade, point, and knife-edge. The term universal micrometer may also refer to a type of micrometer whose frame has modular components, allowing one micrometer to function as outside mic, depth mic, step mic, blade micrometers have a matching set of narrow tips. They allow, for example, the measuring of a narrow o-ring groove, pitch-diameter micrometers have a matching set of thread-shaped tips for measuring the pitch diameter of screw threads. Limit mics have two anvils and two spindles, and are used like a snap gauge, the part being checked must pass through the first gap and must stop at the second gap in order to be within specification. The two gaps accurately reflect the top and bottom of the tolerance range, bore micrometer, typically a three-anvil head on a micrometer base used to accurately measure inside diameters. Tube micrometers have a cylindrical anvil positioned perpendicularly to a spindle and is used to measure the thickness of tubes. Micrometer stops are micrometer heads that are mounted on the table of a milling machine, bedways of a lathe, or other machine tool
19.
Guinness World Records
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The book itself holds a world record, as the best-selling copyrighted book of all time. As of the 2017 edition, it is now in its 63rd year of publication, the international franchise has extended beyond print to include television series and museums. On 10 November 1951, Sir Hugh Beaver, then the director of the Guinness Breweries, went on a shooting party in the North Slob, by the River Slaney in County Wexford. After missing a shot at a golden plover, he involved in an argument over which was the fastest game bird in Europe. That evening at Castlebridge House, he realised that it was impossible to confirm in reference books whether or not the golden plover was Europes fastest game bird. Beaver knew that there must be numerous other questions debated nightly in pubs throughout Ireland and abroad and he realised then that a book supplying the answers to this sort of question might prove successful. Beavers idea became reality when Guinness employee Christopher Chataway recommended University friends Norris and Ross McWhirter, the twin brothers were commissioned to compile what became The Guinness Book of Records in August 1954. A thousand copies were printed and given away, after the founding of The Guinness Book of Records at 107 Fleet Street, the first 198-page edition was bound on 27 August 1955 and went to the top of the British best seller lists by Christmas. The following year, it launched in the US, and sold 70,000 copies, since then, Guinness World Records has become a household name and the global leader in world records. Because the book became a hit, many further editions were printed, eventually settling into a pattern of one revision a year, published in September/October. The McWhirters continued to compile it for many years, Ross McWhirter was assassinated by the Provisional Irish Republican Army in 1975. Following Ross assassination, the feature in the show where questions about records posed by children were answered was called Norris on the Spot, Guinness Superlatives Limited was formed in 1954 to publish the first book. Sterling Publishing owned the rights to the Guinness book in the US for decades, and, under their management, the group was owned by Guinness PLC and subsequently Diageo until 2001, when it was purchased by Gullane Entertainment. Gullane was itself purchased by HIT Entertainment in 2002, with offices in New York City and Tokyo, Guinness World Records global headquarters remain in London, while its museum attractions are based at Ripley headquarters in Orlando, Florida, US. Recent editions have focused on record feats by person competitors, many records also relate to the youngest person who achieved something, such as the youngest person to visit all nations of the world, being Maurizio Giuliano. Each edition contains a selection of the records from the Guinness database, as well as new records. The majority of records are no longer listed in the book or on the website. For those unable to wait the 4–6 weeks for a reply, the Guinness Book of Records is the worlds most sold copyrighted book, earning it an entry within its own pages
20.
Fort Keogh
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Fort Keogh is a former United States Army post located on the western edge of todays Miles City, Montana. It is situated on the bank of the Yellowstone River. It was originally called Tongue River Cantonment for two years, when relocated 1 mile west in 1878, it was renamed Fort Keogh in honor of Captain Myles Keogh, who died at the Battle of the Little Bighorn. In 1877 the fort became the headquarters for the newly created military district, today the former military post is a United States Department of Agriculture livestock and range research station. It is listed on the National Register of Historic Places, the development of Fort Keogh as a military installation soon stimulated traders to supply the liquor and other service businesses that were the beginning of Miles City. The order for development of the fort was signed on August 28,1876, the Armys intended use for its garrison at the post was to reduce warfare by the American Indians in the region and to persuade them to resettle on reservations. Colonel David S. Stanley had originally scouted the first site of the fort during the Yellowstone Expedition of 1873 and he thought the location would be good for supplying troops throughout the region. But, the Army did not decide to build the fort until after Custers overwhelming defeat at the Battle of the Little Bighorn. As the US and developers planned to bring the Great Northern Railway to the region, the troops came into contact with two tribes of Indians, the Lakota and the Crow. The Sioux had pushed the Crow west of their lands as they moved west. Resentful of the Sioux, the Crow frequently allied with the Army, General Miles established the Cantonment Tongue River at the confluence of the north-flowing Tongue River and the east-flowing Yellowstone River. The site would provide access to boats bringing supplies up the Yellowstone. Miles was a well-respected as a leader, not only by his troops, promising fair treatment and better lives to the Native Americans, Miles gradually persuaded the Indian nations to settle on the reservations. Not all the nations surrendered immediately, Miles went to battle against the holdouts with his troops, including during the extreme cold of winter. The Sioux and Crow bands migrated through wide areas in the Montana Territory, and troops were engaged in battle with them hundreds of miles from the fort. The fort was named for Myles Keogh, a Captain and commander of Company I in the 7th US Cavalry under Lt Colonel George Armstrong Custer, born in Ireland on March 25,1840, Keogh came from a comfortable background. Wanting adventure, Keogh left the farming to a brother and went off to war, in 1860 he went to Italy after the Pope recruited Irish men to take up the fight to save the Papal States. In those battles, he won two medals, later Keogh joined the Papal Guard in Rome
21.
Montana
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Montana /mɒnˈtænə/ is a state in the Western region of the United States. The states name is derived from the Spanish word montaña, Montana has several nicknames, although none official, including Big Sky Country and The Treasure State, and slogans that include Land of the Shining Mountains and more recently The Last Best Place. Montana has a 545-mile border with three Canadian provinces, British Columbia, Alberta, and Saskatchewan, the state to do so. It also borders North Dakota and South Dakota to the east, Wyoming to the south, Montana is ranked 4th in size, but 44th in population and 48th in population density of the 50 United States. The western third of Montana contains numerous mountain ranges, smaller island ranges are found throughout the state. In total,77 named ranges are part of the Rocky Mountains, the eastern half of Montana is characterized by western prairie terrain and badlands. The economy is based on agriculture, including ranching and cereal grain farming. Other significant economic activities include oil, gas, coal and hard rock mining, lumber, the health care, service, and government sectors also are significant to the states economy. Millions of tourists annually visit Glacier National Park, the Little Bighorn Battlefield National Monument, the name Montana comes from the Spanish word Montaña and the Latin word Montana, meaning mountain, or more broadly, mountainous country. Montaña del Norte was the name given by early Spanish explorers to the mountainous region of the west. The name was changed by Representatives Henry Wilson and Benjamin F. Harding, when Ashley presented a bill to establish a temporary government in 1864 for a new territory to be carved out of Idaho, he again chose Montana Territory. This time Rep. Samuel Cox, also of Ohio, objected to the name, Cox complained that the name was a misnomer given most of the territory was not mountainous and that a Native American name would be more appropriate than a Spanish one. Other names such as Shoshone were suggested, but it was decided that the Committee on Territories could name it whatever they wanted, with an area of 147,040 square miles, Montana is slightly larger than Japan. It is the fourth largest state in the United States after Alaska, Texas, and California, the largest landlocked U. S. state, and the worlds 56th largest national state/province subdivision. To the north, Montana shares a 545-mile border with three Canadian provinces, British Columbia, Alberta, and Saskatchewan, the state to do so. It borders North Dakota and South Dakota to the east, Wyoming to the south, the states topography is roughly defined by the Continental Divide, which splits much of the state into distinct eastern and western regions. Most of Montanas 100 or more named mountain ranges are in the western half. The Absaroka and Beartooth ranges in the states south-central part are part of the Central Rocky Mountains
22.
Dime (United States coin)
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The dime, in U. S. usage, is a ten-cent coin, one tenth of a United States dollar, labeled formally as one dime. The denomination was first authorized by the Coinage Act of 1792, the dime is the smallest in diameter and is the thinnest of all U. S. coins currently minted for circulation, being.705 inches in diameter and.053 inches in thickness. The obverse of the coin depicts the profile of President Franklin D. Roosevelt and the reverse boasts an olive branch, a torch, as of 2011, the dime coin cost 5.65 cents to produce. The word dime comes from the French word dîme, meaning tithe or tenth part, from the Latin decima. In the past prices have occasionally been quoted on signage and other materials in terms of dimes, abbreviated as d or a d with a slash through it as with the cent. The Coinage Act of 1792 established the dime, cent, and mill as subdivisions of the equal to 1⁄10. The first known proposal for a coinage system in the United States was made in 1783 by Thomas Jefferson, Benjamin Franklin, Alexander Hamilton. Hamilton, the nations first Secretary of the Treasury, recommended the issuance of six such coins in 1791, among the six was a silver coin, which shall be, in weight and value, one tenth part of a silver unit or dollar. Thus dimes are made small and thin, with the passage of the Coinage Act of 1965, the dimes silver content was removed. Dimes from 1965 to the present are composed of layers of 75 percent copper and 25 percent nickel. Starting in 1992, the U. S. Mint began issuing Silver Proof Sets annually and these sets are intended solely for collectors, and are not meant for general circulation. Since its introduction in 1796, the dime has been issued in six different major types, the name for each type indicates the design on the coins obverse. The composition of the disme was set at 89.24 percent silver and 10.76 percent copper, in 1792, a limited number of dismes were minted but never circulated. Some of these were struck in copper, indicating that the 1792 dismes were in fact pattern coins, the first dimes minted for circulation did not appear until 1796, due to a lack of demand for the coin and production problems at the United States Mint. The first dime to be circulated was the Draped Bust dime and it featured the same obverse and reverse as all other circulating coins of the time, the so-called Draped Bust/Small Eagle design. This design was the work of then-Chief Engraver Robert Scot, the portrait of Liberty on the obverse was based on a Gilbert Stuart drawing of prominent Philadelphia socialite Ann Willing Bingham, wife of noted American statesman William Bingham. The reverse design is of a bald eagle surrounded by palm and olive branches. Since the Coinage Act of 1792 required only that the cent and half cent display their denomination, all 1796 dimes have 15 stars on the obverse, representing the number of U. S. states then in the Union
23.
Graupel
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Graupel, also called soft hail or snow pellets, is precipitation that forms when supercooled droplets of water are collected and freeze on falling snowflakes, forming 2–5 mm balls of rime. The term graupel comes from the German language, the METAR code for graupel is GS. Under some atmospheric conditions, snow crystals may encounter supercooled water droplets and these droplets, which have a diameter of about 10 µm, can exist in the liquid state at temperatures as low as −40 °C, far below the normal freezing point. Contact between a crystal and the supercooled droplets results in freezing of the liquid droplets onto the surface of the crystal. This process of growth is known as accretion. Crystals that exhibit frozen droplets on their surfaces are referred to as rimed. When this process continues so that the shape of the snow crystal is no longer identifiable. Graupel was formerly referred to by meteorologists as soft hail, however, graupel is easily distinguishable from hail in both the shape and strength of the pellet and the circumstances in which it falls. Ice from hail is formed in hard, relatively uniform layers, graupel forms fragile, oblong shapes and falls in place of typical snowflakes in wintry mix situations, often in concert with ice pellets. Graupel is also fragile enough that it will fall apart when touched. However, observations of snow crystals with a scanning electron microscope clearly show cloud droplets measuring up to 50 µm on the surface of the crystals. The rime has been observed on all four forms of snow crystals, including plates, dendrites, columns. As the riming process continues, the mass of frozen, accumulated cloud droplets obscures the form of the snow crystal. Graupel commonly forms in high-altitude climates and is denser and more granular than ordinary snow, due to its rimed exterior. Macroscopically, graupel resembles small beads of polystyrene, the combination of density and low viscosity makes fresh layers of graupel unstable on slopes, and layers of 20–30 cm present a high risk of dangerous slab avalanches. In addition, thinner layers of graupel falling at low temperatures can act as ball bearings below subsequent falls of more stable snow. Graupel tends to compact and stabilise approximately one or two days after falling, depending on the temperature and the properties of the graupel, merriam-Webster Online Dictionary, accessed September 12,2006. The Weather Channel, accessed September 12,2006, national Snow and Ice Data Center, accessed September 12,2006
24.
Dihedral group
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In mathematics, a dihedral group is the group of symmetries of a regular polygon, which includes rotations and reflections. Dihedral groups are among the simplest examples of groups, and they play an important role in group theory, geometry. The notation for the group of order n differs in geometry. In geometry, Dn or Dihn refers to the symmetries of the n-gon, in abstract algebra, Dn refers to the dihedral group of order n. The geometric convention is used in this article, a regular polygon with n sides has 2 n different symmetries, n rotational symmetries and n reflection symmetries. Usually, we take n ≥3 here. The associated rotations and reflections make up the dihedral group D n, if n is odd, each axis of symmetry connects the midpoint of one side to the opposite vertex. If n is even, there are n/2 axes of symmetry connecting the midpoints of opposite sides, in either case, there are n axes of symmetry and 2 n elements in the symmetry group. Reflecting in one axis of symmetry followed by reflecting in another axis of symmetry produces a rotation through twice the angle between the axes, as with any geometric object, the composition of two symmetries of a regular polygon is again a symmetry of this object. With composition of symmetries to produce another as the binary operation, the following Cayley table shows the effect of composition in the group D3. R0 denotes the identity, r1 and r2 denote counterclockwise rotations by 120° and 240° respectively, for example, s2s1 = r1, because the reflection s1 followed by the reflection s2 results in a rotation of 120°. The order of elements denoting the composition is right to left, the composition operation is not commutative. In all cases, addition and subtraction of subscripts are to be performed using modular arithmetic with modulus n, if we center the regular polygon at the origin, then elements of the dihedral group act as linear transformations of the plane. This lets us represent elements of Dn as matrices, with composition being matrix multiplication and this is an example of a group representation. For example, the elements of the group D4 can be represented by the eight matrices. In general, the matrices for elements of Dn have the following form, rk is a rotation matrix, expressing a counterclockwise rotation through an angle of 2πk/n. Sk is a reflection across a line makes an angle of πk/n with the x-axis. Further equivalent definitions of Dn are, D1 is isomorphic to Z2, D2 is isomorphic to K4, the Klein four-group. D1 and D2 are exceptional in that, D1 and D2 are the only abelian dihedral groups, Dn is a subgroup of the symmetric group Sn for n ≥3
25.
Hexagonal crystal family
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In crystallography, the hexagonal crystal family is one of the 6 crystal families. In the hexagonal family, the crystal is described by a right rhombic prism unit cell with two equal axes, an included angle of 120° and a height perpendicular to the two base axes. There are 52 space groups associated with it, which are exactly those whose Bravais lattice is either hexagonal or rhombohedral, the hexagonal crystal family consists of two lattice systems, hexagonal and rhombohedral. Each lattice system consists of one Bravais lattice, hence, there are 3 lattice points per unit cell in total and the lattice is non-primitive. The Bravais lattices in the hexagonal crystal family can also be described by rhombohedral axes, the unit cell is a rhombohedron. This is a cell with parameters a = b = c, α = β = γ ≠ 90°. In practice, the description is more commonly used because it is easier to deal with a coordinate system with two 90° angles. However, the axes are often shown in textbooks because this cell reveals 3m symmetry of crystal lattice. However, such a description is rarely used, the hexagonal crystal family consists of two crystal systems, trigonal and hexagonal. A crystal system is a set of point groups in which the point groups themselves, the trigonal crystal system consists of the 5 point groups that have a single three-fold rotation axis. The crystal structures of alpha-quartz in the example are described by two of those 18 space groups associated with the hexagonal lattice system. The hexagonal crystal system consists of the seven point groups such that all their groups have the hexagonal lattice as underlying lattice. Graphite is an example of a crystal that crystallizes in the crystal system. Note that the atom in the center of the HCP unit cell in the hexagonal lattice system does not appear in the unit cell of the hexagonal lattice. It is part of the two atom motif associated with each point in the underlying lattice. The trigonal crystal system is the crystal system whose point groups have more than one lattice system associated with their space groups. The 5 point groups in this system are listed below, with their international number and notation, their space groups in name. The point groups in this system are listed below, followed by their representations in Hermann–Mauguin or international notation and Schoenflies notation
26.
Crystal structure
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In crystallography, crystal structure is a description of the ordered arrangement of atoms, ions or molecules in a crystalline material. Ordered structures occur from the nature of the constituent particles to form symmetric patterns that repeat along the principal directions of three-dimensional space in matter. The smallest group of particles in the material that constitutes the pattern is the unit cell of the structure. The unit cell completely defines the symmetry and structure of the crystal lattice. The repeating patterns are said to be located at the points of the Bravais lattice, the lengths of the principal axes, or edges, of the unit cell and the angles between them are the lattice constants, also called lattice parameters. The symmetry properties of the crystal are described by the concept of space groups, all possible symmetric arrangements of particles in three-dimensional space may be described by the 230 space groups. The crystal structure and symmetry play a role in determining many physical properties, such as cleavage, electronic band structure. The crystal structure of a material can be described in terms of its unit cell, the unit cell is a box containing one or more atoms arranged in three dimensions. The unit cells stacked in three-dimensional space describe the arrangement of atoms of the crystal. Commonly, atomic positions are represented in terms of fractional coordinates, the atom positions within the unit cell can be calculated through application of symmetry operations to the asymmetric unit. The asymmetric unit refers to the smallest possible occupation of space within the unit cell and this does not, however imply that the entirety of the asymmetric unit must lie within the boundaries of the unit cell. Symmetric transformations of atom positions are calculated from the group of the crystal structure. Vectors and planes in a lattice are described by the three-value Miller index notation. It uses the indices ℓ, m, and n as directional parameters, which are separated by 90°, by definition, the syntax denotes a plane that intercepts the three points a1/ℓ, a2/m, and a3/n, or some multiple thereof. That is, the Miller indices are proportional to the inverses of the intercepts of the plane with the unit cell, if one or more of the indices is zero, it means that the planes do not intersect that axis. A plane containing a coordinate axis is translated so that it no longer contains that axis before its Miller indices are determined, the Miller indices for a plane are integers with no common factors. Negative indices are indicated with horizontal bars, as in, in an orthogonal coordinate system for a cubic cell, the Miller indices of a plane are the Cartesian components of a vector normal to the plane. Likewise, the planes are geometric planes linking nodes
27.
Photography
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Typically, a lens is used to focus the light reflected or emitted from objects into a real image on the light-sensitive surface inside a camera during a timed exposure. With an electronic sensor, this produces an electrical charge at each pixel. A negative image on film is used to photographically create a positive image on a paper base, known as a print. The word photography was created from the Greek roots φωτός, genitive of φῶς, light and γραφή representation by means of lines or drawing, several people may have coined the same new term from these roots independently. Johann von Maedler, a Berlin astronomer, is credited in a 1932 German history of photography as having used it in an article published on 25 February 1839 in the German newspaper Vossische Zeitung. Both of these claims are now widely reported but apparently neither has ever been confirmed as beyond reasonable doubt. Credit has traditionally given to Sir John Herschel both for coining the word and for introducing it to the public. Photography is the result of combining several technical discoveries, later Greek mathematicians Aristotle and Euclid also independently described a pinhole camera in the 5th and 4th centuries BCE. Daniele Barbaro described a diaphragm in 1566, wilhelm Homberg described how light darkened some chemicals in 1694. The fiction book Giphantie, published in 1760, by French author Tiphaigne de la Roche, the discovery of the camera obscura that provides an image of a scene dates back to ancient China. Leonardo da Vinci mentions natural camera obscura that are formed by dark caves on the edge of a sunlit valley, a hole in the cave wall will act as a pinhole camera and project a laterally reversed, upside down image on a piece of paper. So the birth of photography was primarily concerned with inventing means to capture, renaissance painters used the camera obscura which, in fact, gives the optical rendering in color that dominates Western Art. The camera obscura literally means dark chamber in Latin and it is a box with a hole in it which allows light to go through and create an image onto the piece of paper. Around the year 1800, British inventor Thomas Wedgwood made the first known attempt to capture the image in a camera obscura by means of a light-sensitive substance and he used paper or white leather treated with silver nitrate. The shadow images eventually darkened all over, the first permanent photoetching was an image produced in 1822 by the French inventor Nicéphore Niépce, but it was destroyed in a later attempt to make prints from it. Niépce was successful again in 1825, in 1826 or 1827, he made the View from the Window at Le Gras, the earliest surviving photograph from nature. Because Niépces camera photographs required a long exposure, he sought to greatly improve his bitumen process or replace it with one that was more practical. With an eye to eventual commercial exploitation, the partners opted for total secrecy, Daguerres efforts culminated in what would later be named the daguerreotype process
28.
Microscope
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A microscope is an instrument used to see objects that are too small for the naked eye. The science of investigating small objects using such an instrument is called microscopy, microscopic means invisible to the eye unless aided by a microscope. There are many types of microscopes, the most common is the optical microscope, which uses light to image the sample. Other major types of microscopes are the microscope, the ultramicroscope. The earliest microscopes were single lens magnifying glasses with limited magnification which date at least as far back as the wide use of lenses in eyeglasses in the 13th century. Compound microscopes, which combine an objective lens with an eyepiece to view a real image, the actual inventor of the compound microscope is unknown although many claims have been made over the years. These include what may be a claim by the son of Zacharias Janssen that his father invented the microscope and telescope as early as 1590. Historians note the compound microscope did not appear in the Netherlands until the 1620s, giovanni Faber coined the name microscope for the compound microscope Galileo submitted to the Accademia dei Lincei in 1625. The first detailed account of the construction of living tissue based on the use of a microscope did not appear until 1644, in Giambattista Odiernas Locchio della mosca. It was not until the 1660s and 1670s that the microscope was used extensively for research in Italy, marcello Malpighi in Italy began the analysis of biological structures, beginning with the lungs. Robert Hookes Micrographia had an impact, largely because of its impressive illustrations. A significant contribution came from Antonie van Leeuwenhoek who achieved up to 300 times magnification using a single lens microscope. He sandwiched a very small glass ball lens between the holes in two metal plates riveted together, and with a needle attached to mount the specimen. Then, Van Leeuwenhoek re-discovered red blood cells and spermatozoa, on 9 October 1676, he reported the discovery of micro-organisms. The performance of light microscopy depends as much on how the sample is illuminated as on how it is observed, early instruments were limited until this principle was fully appreciated and developed, and until electric lamps were available as light sources. In 1893 August Köhler developed a key principle of sample illumination, Köhler illumination and this method of sample illumination produces even lighting and overcomes the limited contrast and resolution imposed by early techniques of sample illumination. In the early 20th century a significant alternative to light microscopy was developed, ernst Ruska started development of the first electron microscope in 1931 which was the transmission electron microscope. The transmission electron microscope works on the principle as an optical microscope but uses electrons in the place of light
29.
Wilson Bentley
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Wilson Alwyn Snowflake Bentley is one of the first known photographers of snowflakes. He perfected a process of catching flakes on black velvet in such a way that their images could be captured before they either melted or sublimated, the broadest collection of Bentleys photographs is held by the Jericho Historical Society in his home town, Jericho, Vermont. Bentley donated his collection of original glass-plate photomicrographs of snow crystals to the Buffalo Museum of Science, a portion of this collection has been digitized and organized into a digital library. Bentley was born on February 9,1865, in Jericho and he first became interested in snow crystals as a teenager on his family farm. He tried to draw what he saw through an old microscope given to him by his mother when he was fifteen and he would capture more than 5,000 images of crystals in his lifetime. Each crystal was caught on a blackboard and transferred rapidly to a microscope slide, even at subzero temperatures, snowflakes are ephemeral because they sublime. Bentley poetically described snowflakes as tiny miracles of beauty and snow crystals as ice flowers, despite these poetic descriptions, Bentley brought a highly objective eye to his work, similar to the German photographer Karl Blossfeldt, who photographed seeds, seed pods, and foliage. In collaboration with George Henry Perkins, professor of history at the University of Vermont. This concept caught the imagination and he published other articles in magazines, including National Geographic, Nature, Popular Science. His photographs have been requested by academic institutions worldwide, in 1931 Bentley worked with William J. Humphreys of the U. S. Weather Bureau to publish Snow Crystals, a monograph illustrated with 2,500 photographs. His other publications include the entry on snow in the edition of Encyclopædia Britannica. Bentley also photographed all forms of ice and natural water formations including clouds and he was the first American to record raindrop sizes and was one of the first cloud physicists. He died of pneumonia at his farm on December 23,1931, Bentley was memorialized in the naming of a science center in his memory at Johnson State College in Johnson, Vermont. Shortly before his death, his book Snow Crystals was published by McGraw-Hill and is still in print today, Bentleys lifelong home is listed on the National Register of Historic Places. The Caldecott Medal winner in 1999 for the childrens book was Snowflake Bentley. Patterns in nature Ukichiro Nakaya Thompson, Jean M. Illustrated by Bentley, water Wonders Every Child Should Know Bentley, Wilson A. The Guide to Nature Bentley, Wilson A, the Magic Beauty of Snow and Dew, National Geographic Bentley, Wilson A. Humphreys, William J. Snow Crystals Bentley, Wilson A. Snow, Encyclopædia Britannica, Vol.20 Knight, N. Bulletin of the American Meteorological Society 69,496 Blanchard, Duncan, the Snowflake Man, A Biography of Wilson A. Bentley, ISBN 0-939923-71-8
30.
Ukichiro Nakaya
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Ukichiro Nakaya was a Japanese physicist and science essayist known for his work in glaciology and low-temperature sciences. He is credited with making the first artificial snowflakes, Nakaya later wrote that his father wanted him to be a potter and sent him to live with a potter while he was in primary school. Nakaya was inspired to study physics in high school by the hypotheses of Kant and Laplace. He majored in physics under Torahiko Terada at Tokyo Imperial University. Soon thereafter, he became Teradas research assistant at the Institute of Physical and Chemical Research, Nakaya studied electrostatic discharge as an assistant professor at Tokyo Imperial University. In 1928 and 1929, he continued his studies at Kings College London under Owen Willans Richardson. When he arrived at Hokkaido University, the department had a minimum of equipment. But there was a supply of natural snow, so Nakaya began his research into snow crystals. From over 3,000 photomicrographs he established a classification of natural snow crystals. In 1935, he opened the Low Temperature Science Laboratory, and on March 12,1936, from 1936 until 1938, Nakaya and his family lived at a hot springs resort on the Izu Peninsula while he recuperated from a bout of clonorchiasis. After his recovery, he began his studies of frost heaving which eventually led to the founding of the Laboratory of Agricultural Physics at Hokkaido University in 1946, in 1941, he received the Imperial Prize of the Japan Academy for his contributions to snow crystal research. In 1943, two years after the Pacific War began, Nakaya moved to a newly built atmospheric icing observatory at Mt. Niseko-Annupuri, a Zero fighter plane was brought to the observatory in the hope of finding ways to prevent atmospheric icing. The following year, Nakaya moved to the Nemuro coast to study artificial dissipation of fog, after the war, he continued his research for the Laboratory of Agricultural Physics into flood and snowmelt in drainage basins. Nakaya always enjoyed field work as well as laboratory research and his studies took him to locations ranging from the top of Mauna Loa, Hawaii to the ice island T-3 in the Canadian Arctic Archipelago. In 1949, on the invitation of the International Glaciological Society, Nakaya toured the United States and Canada, from 1952 until 1954, he was a research fellow at SIPRE. In 1957 he visited Greenland as a member of the United States expedition for the International Geophysical Year and he visited Greenland several more times, usually staying for a month or two at a time, to observe the glaciological ice cap at the latitude 78° observatory site. In 1960, Nakaya underwent surgery for cancer at the hospital at the University of Tokyo. He died on April 11,1962, of osteomyelitis, in recognition of his achievements, he was posthumously decorated with one of the highest orders awarded by the Japanese government
31.
Christmastide
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Christmastide, also known as Twelvetide, is a season of the liturgical year in most Christian churches. Customs of the Christmas season include carol singing, gift giving, seeing Nativity plays, attending church services, traditional examples of Christmas greetings include the Western Christian phrase Merry Christmas and a Happy New Year. and the Eastern Christian greeting Christ is born. To which others respond, Glorify Him, Christmastide begins very early on 25 December. Historically, the ending of Christmastide was 5 January, however, the ending is defined differently by some Christian denominations. In 1969, the Roman Rite of the Catholic Church expanded Christmastide by a number of days. Up to and including the Sunday after Epiphany or after 6 January, in 567, the Council of Tours proclaimed the twelve days from Christmas to Epiphany as a sacred and festive season, and established the duty of Advent fasting in preparation for the feast. The Council held at Tours also spoke of a three-day fast at the beginning of January as an ancient custom, in that canon, which dealt with the fasts to be observed by monks, the council decreed, De ieiuniis. In Augusto, quia quotidie missae sanctorum sunt, prandium habeant, De Decembri usque ad natale Domini, omni die ieiunent. Et quia inter natale Domini et epiphania omni die festivitates sunt, excipitur triduum illud, quo ad calcandam gentilium consuetudinem, patres nostri statuerunt privatas in Kalendis Ianuarii fieri litanias. In medieval era Christendom, Christmastide lasted from the Nativity to the Purification, many Churches refer to the period after the traditional Twelve Days of Christmas and up to Candlemas, as Epiphanytide, also called the Epiphany season. During the Christmas season, various festivities are traditionally enjoyed and buildings are adorned with Christmas decorations and these Christmas decorations include the Nativity Scene, Christmas tree, jingle bells, as well as various Christmas ornaments. In the Western Christian world, the two days on which Christmas decorations are removed are Twelfth Night and Candlemas. Any not removed on the first occasion should be left undisturbed until the second, leaving the decorations up beyond Candlemas is considered to be inauspicious. On Christmas Eve or Christmas Day, the start of Christmastide, it is customary for most households in Christendom to attend a service of worship or Mass, in which they receive Holy Communion. The practice of giving gifts during Christmastide, according to Christian tradition, is symbolic of the presentation of the gifts by the Three Wise Men to the infant Jesus. In the Anglian city of Oxford, many Christian families, after attending church, in several parts of the world, it is common to have a large family feast on Christmas Day, preceded with grace. Throughout the twelve days of Christmastide, many people view Nativity plays, in Russia, Christmastide, understood as the period between Orthodox Christmas and Epiphany, is often referred to as Svyatki. During this period, Russians perform fortunetelling by the use of shadows, candles, wax, maidens who participate in the ceremony have to shed everything that “hinders” the flow of spirits including their belts and rings
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Christian
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A Christian is a person who follows or adheres to Christianity, an Abrahamic, monotheistic religion based on the life and teachings of Jesus Christ. Christian derives from the Koine Greek word Christós, a translation of the Biblical Hebrew term mashiach, while there are diverse interpretations of Christianity which sometimes conflict, they are united in believing that Jesus has a unique significance. The term Christian is also used as an adjective to describe anything associated with Christianity, or in a sense all that is noble, and good. According to a 2011 Pew Research Center survey, there were 2.2 billion Christians around the world in 2010, by 2050, the Christian population is expected to exceed 3 billion. According to a 2012 Pew Research Center survey Christianity will remain the worlds largest religion in 2050, about half of all Christians worldwide are Catholic, while more than a third are Protestant. Orthodox communions comprise 12% of the worlds Christians, other Christian groups make up the remainder. Christians make up the majority of the population in 158 countries and territories,280 million Christian live as a minority. In the Greek Septuagint, christos was used to translate the Hebrew מָשִׁיחַ, in other European languages, equivalent words to Christian are likewise derived from the Greek, such as Chrétien in French and Cristiano in Spanish. The second mention of the term follows in Acts 26,28, where Herod Agrippa II replied to Paul the Apostle, Then Agrippa said unto Paul, Almost thou persuadest me to be a Christian. The third and final New Testament reference to the term is in 1 Peter 4,16, which believers, Yet if as a Christian, let him not be ashamed. The city of Antioch, where someone gave them the name Christians, had a reputation for coming up with such nicknames, in the Annals he relates that by vulgar appellation commonly called Christians and identifies Christians as Neros scapegoats for the Great Fire of Rome. Another term for Christians which appears in the New Testament is Nazarenes which is used by the Jewish lawyer Tertullus in Acts 24, the Hebrew equivalent of Nazarenes, Notzrim, occurs in the Babylonian Talmud, and is still the modern Israeli Hebrew term for Christian. A wide range of beliefs and practices is found across the world among those who call themselves Christian, denominations and sects disagree on a common definition of Christianity. Most Baptists and fundamentalists, for example, would not acknowledge Mormonism or Christian Science as Christian, in fact, the nearly 77 percent of Americans who self-identify as Christian are a diverse pluribus of Christianities that are far from any collective unity. The identification of Jesus as the Messiah is not accepted by Judaism, the term for a Christian in Hebrew is נוּצְרי, a Talmudic term originally derived from the fact that Jesus came from the Galilean village of Nazareth, today in northern Israel. Adherents of Messianic Judaism are referred to in modern Hebrew as יְהוּדִים מָשִׁיחַיים, the term Nasara rose to prominence in July 2014, after the Fall of Mosul to the terrorist organization Islamic State of Iraq and the Levant. The nun or ن— the first letter of Nasara—was spray-painted on the property of Christians ejected from the city, where there is a distinction, Nasrani refers to people from a Christian culture and Masihi is used by Christians themselves for those with a religious faith in Jesus. In some countries Nasrani tends to be used generically for non-Muslim Western foreigners, another Arabic word sometimes used for Christians, particularly in a political context, is Ṣalībī from ṣalīb which refers to Crusaders and has negative connotations
33.
Incarnation (Christianity)
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The doctrine of the Incarnation, then, entails that Jesus Christ is fully God and fully human, his two natures joined in hypostatic union. This is central to the traditional faith held by most Christians, alternative views on the subject have been proposed throughout the centuries, but all were rejected by mainstream Christian bodies. An alternative doctrine known as Oneness has been espoused among various Pentecostal groups, the noun incarnation derives from the ecclesiastical Latin verb incarno, itself derived from the prefix in- and caro, flesh, meaning to make into flesh or, in the passive, to be made flesh. The verb incarno does not occur in the Latin Bible but the term is drawn from the Gospel of John et Verbum caro factum est, Incarnation refers to the act of a pre-existent divine being, the Son of God, in becoming a human being. While all Christians believed that Jesus was indeed the Son of God, justin Martyr argued that the incarnate Word was pre-figured in Old Testament prophecies. Eventually, teaching of Alexander, Athanasius, and the other Nicene Fathers, all divergent beliefs were defined as heresies. This included Docetism, Arianism, Nestorianism, and Sabellianism, the most widely accepted definitions of the Incarnation and the nature of Jesus were made by the First Council of Nicaea in 325, the Council of Ephesus in 431, and the Council of Chalcedon in 451. These councils declared that Jesus was both fully God, begotten from, but not created by the Father, and fully man, taking his flesh and these two natures, human and divine, were hypostatically united into the one personhood of Jesus Christ. Without diminishing his divinity, he added to it all that is involved in being human, in Christian belief it is understood that Jesus was at the same time both fully God and fully human, two persons in one nature. The body of Christ was therefore subject to all the bodily weaknesses to which nature is universally subject, such are hunger, thirst, fatigue, pain. They were the results of the human nature He assumed. The significance of the Incarnation has been discussed throughout Christian history. The link between the Incarnation and the Atonement within systematic theology is complex, in his work The Trinity and the Kingdom of God, Jürgen Moltmann differentiated between what he called a fortuitous and a necessary Incarnation. The latter gives a soteriological emphasis to the Incarnation, the Son of God became a man so that he could save us from our sins. The former, on the hand, speaks of the Incarnation as a fulfilment of the Love of God, of his desire to be present and living amidst humanity. Moltmann favours fortuitous Incarnation primarily because he feels that to speak of an Incarnation of necessity is to do an injustice to the life of Christ, moltmanns work, alongside other systematic theologians, opens up avenues of liberation Christology. The Son of God, Servetus asserted, is not an existing being. For this reason, Servetus refused to call Christ the eternal Son of God preferring the Son of the eternal God instead, in describing Servetus theology of the Logos, Andrew Dibb comments, In Genesis God reveals himself as the creator
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Jesus in Christianity
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Christians believe that Jesus is the Messiah and believe that through his death and resurrection, humans can be reconciled to God and thereby are offered salvation and the promise of eternal life. The choice Jesus made thus counter-positions him as a new man of morality and obedience, most Christians believe that Jesus was both human and divine—the Son of God. Jesus, having become fully human in all respects, suffered the pains and temptations of a mortal man, as fully God, he defeated death and rose to life again. According to the Bible, God raised him from the dead and he ascended to heaven to sit at the Right Hand of God, and he will return to earth again for the Last Judgment and the establishment of the Kingdom of God in the World to Come. Although Christian views of Jesus vary, it is possible to summarize key elements of the shared beliefs among major denominations based on their catechetical or confessional texts. Christian views of Jesus are derived from biblical sources, particularly from the canonical Gospels. Christians predominantly hold that these works are historically true and those groups or denominations committed to what are considered biblically orthodox Christianity nearly all agree on the following points, Christians believe that the mother of Jesus was a virgin. Christians believe that Jesus was a human being who was also fully God, Christians believe that Jesus came into the world as the son of only one earthly parent, Mary. Christians believe that Jesus never sinned or did anything wrong, Christians believe that Jesus was eventually martyred, was buried in a tomb, and then on the third day came back to life. Christians believe that because he rose from the tomb on the third day, Christians believe that Jesus eventually ascended back to God the Father. Christians believe that Jesus will come back to earth a second time, the five major milestones in the gospel narrative of the life of Jesus are his Baptism, Transfiguration, Crucifixion, Resurrection and Ascension. These are usually bracketed by two episodes, his Nativity at the beginning and the sending of the Paraclete at the end. The gospel accounts of the teachings of Jesus are often presented in terms of specific categories involving his works and words, e. g. his ministry, Christians not only attach theological significance to the works of Jesus, but also to his name. Devotions to the name of Jesus go back to the earliest days of Christianity and these exist today both in Eastern and Western Christianity—both Catholic and Protestant. Christians predominantly profess that through Jesus life, death, and resurrection and his death on a cross is understood as a redemptive sacrifice, the source of humanitys salvation and the atonement for sin which had entered human history through the sin of Adam. But who do you say that I am, only Simon Peter answered him, You are the Christ, the Son of the living God — Matthew 16, 15-16 Jesus is mediator, but…the title means more that someone between God and man. He is not just a third party between God and humanity…, as true God he brings God to mankind. As true man he brings mankind to God, most Christians generally consider Jesus to be the Christ, the long awaited Messiah, as well as the one and only Son of God
35.
Justification (theology)
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Justification, in Christian theology, is Gods act of removing the guilt and penalty of sin while at the same time declaring a sinner righteous through Christs atoning sacrifice. The means of justification is an area of significant difference between Catholicism, Orthodoxy and Protestantism, even within the latter, in Lutheranism and Calvinism, righteousness from God is viewed as being credited to the sinners account through faith alone, without works. Justification is granted to all who exercise faith, and that is viewed as a gift from God by Lutherans and Calvinists, in Methodism, justification refers to pardon and the forgiveness of sins and sanctification is the consequent process that together, will ultimately lead to ones salvation. Catholics, Orthodox and Methodists use James 2, 14-26, Galatians 5, 19-21, Justification is often seen as being the theological fault line that divided Catholic from the Lutheran and Reformed traditions of Protestantism during the Reformation. Jesus used the idea of ransom, or redemption when referring to his work on earth, Christs death and resurrection provide justification for believers before God. His righteousness becomes theirs, and his death becomes an offering to God in their place, According to Protestants this justification is by faith alone - not through good deeds - and is a gift from God through Christ. But also for us, to whom God will credit righteousness—for us who believe in him who raised Jesus our Lord from the dead and he was delivered over to death for our sins and was raised to life for our justification. This righteousness is given through faith in Jesus Christ to all who believe. There is no difference between Jew and Gentile, for all have sinned and fall short of the glory of God, God presented Christ as a sacrifice of atonement, through the shedding of his blood—to be received by faith. I warn you, as I warned you before, that those who do such things will not inherit the kingdom of God, if you would enter life, keep the commandments. You shall not murder, You shall not commit adultery, You shall not steal, whoever believes and is baptized will be saved, but whoever does not believe will be condemned. You see that a person is justified by what he does, but faith without works is dead. When the justified live in Christ and act in the grace they receive, they bring forth, in biblical terms, since Christians struggle against sin their entire lives, this consequence of justification is also for them an obligation they must fulfill. Thus both Jesus and the apostolic Scriptures admonish Christians to bring forth the works of love, an example can be cited from section 4.7 no. 38-39, when Catholics affirm the character of good works, they wish to say that, according to the biblical witness. They do emphasize that righteousness as acceptance by God and sharing in the righteousness of Christ is always complete, at the same time, they state that there can be growth in its effects in Christian living. Suppose a brother or sister is without clothes and daily food, if one of you says to him, Go, I wish you well, keep warm and well fed, but does nothing about his physical needs, what good is it. In the same way, faith by itself, if it is not accompanied by action, is dead, but someone will say, You have faith, I have deeds
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Christian views on sin
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The doctrine of sin is central to Christianity, since its basic message is about redemption in Christ. Christian hamartiology describes sin as an act of offence against God by despising his persons and Christian biblical law, in Christian views it was an evil human act, which violates the rational nature of man as well as Gods nature and his eternal law. According to the definition of St. Augustine of Hippo sin is a word, deed. As with the definition of sin, this definition also affects the understanding of Christian grace and salvation. The first reference to sin as a noun is of sin is crouching at your door, it desires to have you, but you must rule over it” waiting to be mastered by Cain, a form of literary theriomorphism. The first use of the verb is God appears to Abimelech in the dream, “Yes, I know you did this with a clear conscience, and so I have kept you from sinning against me. That is why I did not let you touch her. ”Isaiah announced the consequences, But your iniquities have separated you from your God, your sins have hidden his face from you, for your hands are stained with blood, your fingers with guilt. Your lips have spoken falsely, and your tongue mutters wicked things — a separation between God and man, and unrequited worshipping, the concept of original sin was first alluded to in the 2nd century by Irenaeus, Bishop of Lyon in his controversy with certain dualist Gnostics. Other church fathers such as Augustine also developed the doctrine, seeing it as based on the New Testament teaching of Paul the Apostle, tertullian, Cyprian, Ambrose and Ambrosiaster considered that humanity shares in Adams sin, transmitted by human generation. The Jansenist movement, which the Catholic Church declared to be heretical, the way Thomas Aquinas viewed sin and vices was radically different from later approaches, especially that of 17th century moral theology. He presented sin and vices as contraries of virtues and he discusses the subject in his Summa Theologica part Ia-IIae qq. 71-89. In one of his definitions of sin Thomas quotes Augustine of Hippos description of sin as a thought, words and deed against the Eternal Law. Now there are two rules of the human will, one is proximate and homogeneous, viz. the human reason, the other is the first rule, viz. the eternal law, which is Gods reason, so to speak. To recognise the possibilities of sin in man is equal to acknowledge his human nature, his control, sin is a motion to the goal, it is judged by the object to which it is directed. The field of sin is the same as the field of virtue, there are three major fields, relationship with God, with oneself and with the neighbour. Thomas distinguished between mortal and venial sins, mortal sin is when a person has irreparably destroyed the very principle of his/her order to the goal of life. According to Aquinas the gravity of sin depends also on some disposition of the agent, sin, venial by reason of its object, may become mortal. It happens when person fixes his/her ultimate happiness, the last end of life in the object of that venial sin
37.
Christian symbolism
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Christian symbolism is the use of symbols, including archetypes, acts, artwork or events, by Christianity. It invests objects or actions with an inner meaning expressing Christian ideas, the symbolism of the early Church was characterized by being understood by initiates only, while after the legalization of Christianity in the 4th-century more recognizable symbols entered in use. Christianity has borrowed from the stock of significant symbols known to most periods. The shape of the cross, as represented by the letter T, at the end of the 2nd century, it is mentioned in the Octavius of Minucius Felix, rejecting the claim by detractors that Christians worship the cross. In his book De Corona, written in 204, Tertullian tells how it was already a tradition for Christians to trace repeatedly on their foreheads the sign of the cross. An early example of the halo, used to identify Christ in paintings, is found in the Miracles of the Loaves and Fishes mosaic of SantApollinare Nuovo. Instances of the St Thomas cross, a Greek cross with clover leaf edges, popular in southern India, the Patriarchal cross, a Latin cross with an additional horizontal bar, first appears in the 10th century. Although the cross was used as a symbol by early Christians, the purported discovery of the True Cross by Constantines mother, Helena, and the development of Golgotha as a site for pilgrimage led to a change of attitude. In the early period, the plain cross became depicted as the crux gemmata, covered with jewels. The first depictions of crucifixion displaying suffering are believed to have arisen in Byzantine art, Early Western examples include the Gero Cross and the reverse of the Cross of Lothair, both from the end of the 10th century. Marie-Madeleine Davy described in great detail Romanesque Symbolism as it developed in the Middle Ages in Western Europe, among the symbols employed by the early Christians, that of the fish seems to have ranked first in importance. The Staurogram ⳨, also Monogrammatic Cross or Tau-Rho symbol, is composed by a tau superimposed on a rho, in such a way the symbol expresses the idea that the Cross saves. The two letters tau and rho can also be found separately as symbols on early Christian ossuaries, the Monogrammatic Cross was later seen also as a variation of the Chi Rho symbol, and it spread over Western Europe in the 5th and 6th centuries. The Chi Rho is formed by superimposing the first two letters chi and rho of the Greek word ΧΡΙΣΤΟΣ =Christ in such a way to produce the monogram, widespread in ancient Christianity, it was the symbol used by the Roman emperor Constantine I as vexillum. This symbol was explained in the Epistle of Barnabas and by Clement of Alexandria. For other christograms such as IHS, see Article Christogram, initially it was also understood as a symbol like others used in Early Christian art. By about the 5th century the more often took on the appearance of the conventional depiction of Christ, as it had developed by this time. The dove as a Christian symbol is of frequent occurrence in ancient ecclesiastical art
38.
White Christmas (weather)
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A white Christmas refers to the presence of snow at Christmas, either Christmas Eve or Christmas Day depending on local tradition. This phenomenon is most common in the countries of the Northern Hemisphere. The Irving Berlin song, White Christmas, sung by Bing Crosby from the film Holiday Inn, is the single of all time. The definition of White Christmas varies, in most countries, it simply means that the ground is covered by snow at Christmas, but some countries have more strict definitions. In the United Kingdom the most likely place to see snowfall on a Christmas Day is in North and North Eastern Scotland, in Aberdeen, the definition of a white Christmas in Canada is 2 cm of snow-cover or more on Christmas morning at 7 am. Environment Canada started to analyze data from 1955 to 2013 for a total of 59 years, the year 2006 saw some of the warmest weather on record, with such places as Quebec City experiencing their first green Christmas in recorded history. In 2008, Canada experienced the first nationwide white Christmas in 37 years, as a series of storms hit the nation. The 2004 storm also brought the first measurable snow of any kind since 1895 to Brownsville, Texas, the Florida winter storm of 1989 also occurred immediately before Christmas causing a white Christmas for cities like Pensacola and Jacksonville. The same storm buried Wilmington, North Carolina and the rest of Southeastern North Carolina under 38 cm of snow, White Christmas is an Irving Berlin song reminiscing about an old-fashioned Christmas setting. The National Climatic Data Center based the probability of a white Christmas at selected cities upon the 1988–2005 numbers from stations with at least 25 years of data, in the United Kingdom, white Christmases were more common from the 1550s to the 1850s, during the Little Ice Age. The shift from the Julian to the Gregorian calendar in 1752 also slightly reduced the chance of a white Christmas, during the 20th century there were only seven official white Christmases in the United Kingdom. Although most places in the UK do tend to see snow in the winter. However white Christmases do occur, on average every 6 years, Christmas 2009 was a white Christmas in some parts of Britain, with thick lying snow which easterly winds had brought over the previous week. Travel over much of Britain was badly affected by ice and snow on roads and it was the first white Christmas anywhere in the United Kingdom since 2004. In Ireland, the prospect of winter snow is always remote due to the countrys mild. Bookmakers offer odds every year for a white Christmas, which is officially lying snow being recorded at 09,00 local time on Christmas Day, and recorded at either Dublin Airport or Cork Airport. Since 1961, countrywide, snow has fallen on 17 Christmas Days, the maximum amount of lying snow ever recorded on Christmas Day was 27 cm at Casement Aerodrome in 2010. At Dublin Airport, there have been 12 Christmas Days with snowfall since 1941, the statistical likelihood of snow falling on Christmas Day at Dublin Airport is approximately once every 5.9 years
39.
Tire
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A tire or tyre is a ring-shaped vehicle component that covers the wheels rim to protect it and enable better vehicle performance. Most tires, such as those for automobiles and bicycles, provide traction between the vehicle and the road providing a flexible cushion that absorbs shock. The materials of modern tires are synthetic rubber, natural rubber, fabric and wire, along with carbon black. They consist of a tread and a body, the tread provides traction while the body provides containment for a quantity of compressed air. Before rubber was developed, the first versions of tires were bands of metal fitted around wooden wheels to prevent wear and tear. Pneumatic tires are used on many types of vehicles, including cars, bicycles, motorcycles, buses, trucks, heavy equipment, and aircraft. Metal tires are used on locomotives and railcars, and solid rubber tires are still used in various non-automotive applications, such as some casters, carts, lawnmowers. The etymology of tire is that the word is a form of attire. The spelling tyre does not appear until the 1840s when the English began shrink fitting railway car wheels with malleable iron, nevertheless, traditional publishers continued using tire. The Times newspaper in Britain was still using tire as late as 1905, the spelling tyre began to be commonly used in the 19th century for pneumatic tires in the UK. However, over the course of the 20th century, tyre became established as the standard British spelling, the earliest tires were bands of leather, then iron, placed on wooden wheels, used on carts and wagons. The tire would be heated in a fire, placed over the wheel and quenched, causing the metal to contract. A skilled worker, known as a wheelwright, carried out this work, the outer ring served to tie the wheel segments together for use, providing also a wear-resistant surface to the perimeter of the wheel. The word tire thus emerged as a variant spelling to refer to the bands used to tie wheels. The first patent for what appears to be a standard pneumatic tire appeared in 1847 lodged by the Scottish inventor Robert William Thomson, however, this never went into production. The first practical pneumatic tire was made in 1888 on May Street, Belfast, by Scots-born John Boyd Dunlop and it was an effort to prevent the headaches of his 10-year-old son Johnnie, while riding his tricycle on rough pavements. His doctor, John, later Sir John Fagan, had prescribed cycling as an exercise for the boy, Fagan participated in designing the first pneumatic tires. In Dunlops tire patent specification dated 31 October 1888, his interest is only in its use in cycles, in September 1890, he was made aware of an earlier development but the company kept the information to itself
40.
1968 Winter Olympics
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The 1968 Winter Olympics, officially known as the X Olympic Winter Games, were a winter multi-sport event which was celebrated in 1968 in Grenoble, France and opened on 6 February. Norway won the most medals, the first time a country other than the USSR had done so since the USSR first entered the Winter Games in 1956, frenchman Jean-Claude Killy won three gold medals in all the alpine skiing events. In womens figure skating, Peggy Fleming won the only United States gold medal, the year 1968 marked the first time the IOC first permitted East and West Germany to enter separately, and the first time the IOC ever ordered drug and gender testing of competitors. The application was given to the IOC during a meeting between IOC executives and representatives of international sport agencies in Lausanne in February 1963. Between 1946 and 1962 the number of inhabitants in Grenoble increased from 102,000 to 159,000, the development of the infrastructure could not keep up with this rapid increase and was for the most part at the same level as before the Second World War. The 61st IOC session, where the awarding of the Olympic Games should have been voted for and this session was moved to Baden-Baden because Kenya refused entry to IOC members from Portugal and South Africa for political reasons. Due to a lack of time only the Summer Games of 1968 could be voted for, the vote finally took place in Innsbruck on 28 January 1964, one day before the start of the 1964 Winter Olympic Games. After Grenoble was voted as the host city the French National Olympic Sports Committee decided the foundation of the organisation committee. The Comité d’Organisation des dixièmes Jeux Olympiques, the committee for the organisation of the 10th Olympic Games, albert Michallon, alongside being the former mayor of Grenoble, was also president of COJO. The upper panel was made up of the assembly with its 340 members and the supervisory board conduct business with 39 members,19 of which were appointed. The general secretary consisted of five departments and 17 subordinate departments. The number of employees grew to 1920 in February 1968, minister for Youth and Sport Francois Missoffe formed an interministerial committee for the coordination of the work commissioned by prime minister Georges Pompidou. Just over 7000 soldiers of the French armed forces and also employees of the ministries for Youth and Sport, Finance, Social Building, Education, Post, Culture, the sum of the investments contributed to 1.1 billion Francs. The government contributed 47. 08%, the Isere Department 3. 65%, the city of Grenoble 20. 07% and the surrounding communities 1. 37%. Different institutions, such as the train company SNCF, the television broadcaster ORTF, the government housing association, to test the new sport complex and to improve organisational processes they organized International Sports Weeks. From 20 January to 19 February 1967 speed skating competitions and ski races took place, from 12 to 15 October 1967 an ice hockey tournament, on 16 December 1967, the olympic torch was lit in ancient Olympia in Greece. The route of the relay at first led over Mount Olympus to Athens. From there, the torch was flown by an Air France Boeing 707 to the Paris-Orly airport
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1972 Winter Olympics
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The 1972 Winter Olympics, officially known as the XI Olympic Winter Games, were a winter multi-sport event which was held from February 3 to February 13,1972, in Sapporo, Hokkaidō, Japan. It was the first Winter Olympics to be held outside Europe and North America, Sapporo first won the rights to host the 1940 Winter Olympics, but Japan resigned as the Games host after its 1937 invasion of China. The 1940 Games were later cancelled, all the cities awarded Games that were cancelled due to war have since hosted the Games. Sapporo competed with Banff, Lahti, and Salt Lake City, the Games were awarded at the 64th IOC Session in Rome, Italy, on April 26,1966. In preparation, the Japanese constructed new facilities at Sapporo. The Games organizers themselves turned a profit in part because they arranged a record $8.47 million for broadcast rights. Prior to these games, Japan had never won a medal in the Winter Olympics. The host countrys fans in Sapporo were booed when three Japanese athletes, led by Yukio Kasaya, swept the ski jumping 70 m event for gold, silver, galina Kulakova of the USSR won all three cross-country skiing events for women. Dutch skater Ard Schenk won three medals in speed skating. In Womens Alpine Skiing, American Barbara Ann Cochran, one of three siblings on the U. S, in Alpine skiing, virtual unknown Swiss Marie-Thérès Nadig won both the downhill and the giant slalom events. Magnar Solberg from Norway was the first repeat winner in the individual 20 km biathlon event, spain scored its first Winter gold medal courtesy of slalom skier Francisco Fernández Ochoa. American speedskaters Anne Henning and Dianne Holum made the United States best showing in the Winter Games, three days before the Games, controversy over amateur status arose when IOC president Avery Brundage threatened to disqualify 40 alpine skiers who received endorsement and other deals. Austrian skier Karl Schranz, who received over $50,000 per year from ski manufacturers, was banned as an example, meanwhile, Canada refused to send an ice hockey team, maintaining that professional ice hockey players from Communist nations were allowed to compete with no restrictions. On a historical note, these Games are the last where a skier won the gold medal using all-wooden skis, since this time, top-level cross-country skiers use skis made mostly of fibreglass synthetics. Luge had its only tie in the history of the Winter Olympics in the doubles event. Teine Alpine Skiing courses¹ – alpine skiing Mt. Teine Bobsleigh Course – bobsleigh Mt. ² Existing facilities modified or refurbished in preparation for the Olympic Games, there were 35 events contested in 6 sports. 35 nations participated in the 1972 Winter Olympics, the Republic of China and the Philippines participated in their first Winter Olympic Games. These are the top ten nations that won medals at these Games, the host nation Japan finished 11th
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1988 Winter Olympics
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The 1988 Winter Olympics, officially known as the XV Olympic Winter Games, was a Winter Olympics multi-sport event celebrated in and around Calgary, Alberta, Canada between February 13 and 28,1988. The host city was selected in 1981 over Falun, Sweden and Cortina dAmpezzo, most events took place in Calgary while several skiing events were held in the mountain resorts of Nakiska and Canmore, west of the city. A then-record 57 nations competed and 1,423 athletes participated, the Soviet Union won the most medals with 29, followed by East Germany with 25. As it had in Montreal in 1976, Canada again failed to win a medal in an official medal event as the host nation. Finnish ski jumper Matti Nykänen and Dutch speed skater Yvonne van Gennip were individual medal leaders, the bid for the 1988 Winter Olympics was Canadas seventh attempt at hosting a winter games and Calgarys fourth. Previous bids representing Montreal and Vancouver bookended failed attempts by the Calgary Olympic Development Association to host the 1964,1968 and 1972 games. The CODA became dormant in 1966 after losing its bid for the 1972 Olympics, Calgary earned the right to bid on behalf of Canada by the Canadian Olympic Association, defeating a rival challenge from a group representing Vancouver. The defeated organizing group lamented that they lost to Calgarys big-ticket games, the CODA then spent two years building local support for the project, selling memberships to 80,000 of the citys 600,000 residents. The city was one of three finalists, opposed by the Swedish community of Falun and Cortina dAmpezzo, the Italian town that hosted the 1956 Winter Olympics. The vote was held September 30,1981, at Baden-Baden, West Germany, during the 84th IOC Session, after Cortina dAmpezzo was eliminated in the first round of balloting, Calgary won the right to host the games over Falun by a 48–31 vote. The announcement of the CODAs victory sent delegates in Baden-Baden and residents of Calgary into celebration and it was the first Winter Olympics awarded to Canada, and the second games overall, following the 1976 Summer Olympics in Montreal. McMahon Stadium, Calgarys primary outdoor facility, was the site of both the opening and closing ceremonies, the first time in 28 years that the venue hosted both events. Three other existing venues served as secondary facilities, The Max Bell Centre hosted the events of curling. The Father David Bauer Olympic Arena hosted some ice hockey matches, as did the Stampede Corral, the Games five primary venues were all purpose-built however, at significant cost. The Olympic Saddledome was the venue for ice hockey and figure skating. Located at Stampede Park, the facility was expected to cost $83 million, the Olympic Oval was built on the campus of the University of Calgary. It was the first fully enclosed 400-metre speed skating venue in the world as it was necessary to protect against the possibility of either bitter cold temperatures or ice-melting chinook winds. Seven world and three Olympic records were broken during the Games, resulting in the facility earning praise as the fastest ice on Earth, Canada Olympic Park was built on the western outskirts of Calgary and hosted bobsled, luge, ski jumping and freestyle skiing
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1998 Winter Olympics
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The 1998 Winter Olympics, officially the XVIII Olympic Winter Games, was a winter multi-sport event celebrated from 7 to 22 February 1998 in Nagano, Japan. 72 nations and 2,176 participants contested in 7 sports and 68 events at 15 venues, the Games saw the introduction of womens ice hockey, curling and snowboarding. National Hockey League players were allowed to participate in the ice hockey. The host was selected on June 15,1991, over Salt Lake City, Östersund, Jaca and they were the third Olympic Games and second winter Olympics to be held in Japan, after the 1964 Summer Olympics in Tokyo and the 1972 Winter Olympics in Sapporo. Nagano is so far the southernmost city to host a Winter Olympics, next to Squaw Valley, the games were succeeded by the 1998 Winter Paralympics from 5 to 14 March. These were the final Winter Olympic Games under the IOC Presidency of Juan Antonio Samaranch, other candidate cities for the 1998 Olympics were Aosta, Italy, Jaca, Spain, Östersund, Sweden, and Salt Lake City, United States. The host city selection was held in Birmingham, United Kingdom, on 15 June 1991, Nagano prevailed over Salt Lake City by just 4 votes. In June 1995, Salt Lake was chosen as the host of the following 2002 Winter Olympics, the Nagano Olympic bid committee spent approximately $14 million to entertain the 62 International Olympic Committee members and many of their companions. The precise figures are unknown since Nagano, after the IOC asked that the entertainment expenditures not be made public, sukki, Nokki, Lekki and Tsukki, also known as the Snowlets are the 1998 Winter Olympic mascots and are four snowy owls. They represent respectively fire, air, earth and water and together represent the four major islands of Japan. Australia Seven Network China CCTV United Kingdom BBC Bjørn Dæhlie won 3 gold medals in skiing, making him the Winter Olympic competitor with the most wins ever. Alpine skier Hermann Maier survived a fall in the downhill and went on to win gold in the super-G, Netherlands won 5 of the 10 speed skating events, including 2 each by Gianni Romme and Marianne Timmer. Canada beat Denmark in the womens curling final, securing the latter their first Winter Olympic medal ever, womens ice hockey was contested at the Olympic Games for the first time ever, and the United States beat the Canadians 3–1 for the gold medal. United States went undefeated in the womens tournament, the Czech Republic defeated Russia by a score of 1–0 for the mens gold medal, while Finland won both the mens and womens bronze medals for ice hockey. Cross-country skier Bjørn Dæhlie of Norway won three medals in Nordic skiing to become the first winter Olympian to earn eight career gold medals. Curling returned as a sport, after having been demoted to a demonstration event after the inaugural Winter Games in Chamonix in 1924. Snowboarding debuted as an official sport, players from the NHL were able to compete in mens ice hockey due to a three-week suspension of the NHL season. Tara Lipinski,15, narrowly beat Michelle Kwan in womens figure skating to become the youngest champion in an event in the history of the Winter Olympics
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2002 Winter Olympics
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Approximately 2,400 athletes from 78 nations participated in 78 events in fifteen disciplines, held throughout 165 sporting sessions. The 2002 Winter Olympics and the 2002 Paralympic Games were both organized by the Salt Lake Organizing Committee, Utah became the fifth state in the United States to host the Olympic Games, and the 2002 Winter Olympics are the most recent games to be held in the United States. These were the first Olympic Games under the IOC presidency of Jacques Rogge, the opening ceremony was held on February 8,2002, and sporting competitions were held up until the closing ceremony on February 24,2002. Production for both ceremonies was designed by Seven Nielsen, and music for both ceremonies was directed by Mark Watters, Salt Lake City became the most populous area ever to have hosted the Winter Olympics, although the two subsequent host cities populations were larger. Following a trend, the 2002 Olympic Winter Games were also larger than all prior Winter Games, with 10 more events than the 1998 Winter Olympics in Nagano, Japan. The Salt Lake Games faced a scandal and some local opposition during the bid. Nevertheless, from sporting and business standpoints, this was one of the most successful Winter Olympiads in history, over 2 billion viewers watched more than 13 billion viewer-hours. The Games were also financially successful raising more money with fewer sponsors than any prior Olympic Games, the surplus was used to create the Utah Athletic Foundation, which maintains and operates many of the remaining Olympic venues. U. S. Federal subsidies amounted to $1.3 billion, Salt Lake City was chosen over Québec City, Canada, Sion, Switzerland, and Östersund, Sweden, on June 16,1995, at the 104th IOC Session in Budapest, Hungary. The 1976 Winter Olympics were ultimately awarded to Innsbruck, Austria, 1Because of the no-commercialization policy of the Olympics, the Delta Center, now the Vivint Smart Home Arena, was labeled as the Salt Lake Ice Center, causing some confusion for visitors. The Oxford Olympics Study established the outturn cost of the Salt Lake City 2002 Winter Olympics at USD2.5 billion in 2015-dollars and cost overrun at 24% in real terms. This includes sports-related costs only, that is, operational costs incurred by the committee for the purpose of staging the Games. The competition venues, the Olympic village, international broadcast center, and media and press center, average cost for Winter Games since 1960 is USD3.1 billion, average cost overrun is 142%. A total 78 National Olympic Committees sent athletes to the Salt Lake City games, cameroon, Hong Kong, Nepal, Tajikistan, and Thailand participated in their first Winter Olympic Games. There were 78 events contested in 7 sports, in the following calendar for the 2002 Winter Olympic Games, each blue box represents an event competition, such as a qualification round, on that day. The yellow boxes represent days during which medal-awarding finals for a sport are held, the number in each box represents the number of finals that were contested on that day. All dates are in Mountain Standard Time Host country To sort this table by nation, total medal count, or any other column, several medals records were set and/or tied. They included, Norway tied the Soviet Union at the 1976 Winter Olympics for most gold medals at a Winter Olympics, germany set a record for most total medals at a Winter Olympics, with 36
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Snowflake (heraldry)
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The snowflake or snow crystal, is a charge in heraldry. The display in coats of arms is following a strictlt stylized form of the six pointed crystal form of a snowflake. In older heraldic literature, this charge is not to be seen, in modern heraldry, the snowflake is most used in northern Europe, in arms in Sweden, Norway and Finland, where it alludes to the meteorological features of the lands. Otherwise, it also is a symbol for winter, and together with the sun the changing seasons, walter Leonhard, Das große Buch der Wappenkunst. Bechtermünz, Augsburg 2001, ISBN 3-8289-0768-7, S.261
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