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Needle Ice
Needle ice is a needle-shaped column of ice formed by groundwater. Needle ice forms when the temperature of the soil is above and the surface temperature of the air is below . Liquid water underground rises to the surface by capillary action, and then freezes and contributes to a growing needle-like ice column. Needle ice requires a flowing form of water underneath the surface, from that point it comes into contact with air that is below freezing. This area of the process usually occurs at night when temperature reaches its low point. From then on, it produces the needle like structure known as "Needle Ice". The ice needles are typically a few centimetres long. While growing, they may lift or push away small soil particles. On sloped surfaces, needle ice may be a factor contributing to soil creep.Isbell, D.: Needle Ice on Mt. Osceola'', EPOD of July 10, 2005. URL last accessed 2007-12-07.Pidwirny, M. URL last accessed 2007-12-07. Alternate names for needle ice are "frost pil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Needle Ice
Needle ice is a needle-shaped column of ice formed by groundwater. Needle ice forms when the temperature of the soil is above and the surface temperature of the air is below . Liquid water underground rises to the surface by capillary action, and then freezes and contributes to a growing needle-like ice column. Needle ice requires a flowing form of water underneath the surface, from that point it comes into contact with air that is below freezing. This area of the process usually occurs at night when temperature reaches its low point. From then on, it produces the needle like structure known as "Needle Ice". The ice needles are typically a few centimetres long. While growing, they may lift or push away small soil particles. On sloped surfaces, needle ice may be a factor contributing to soil creep.Isbell, D.: Needle Ice on Mt. Osceola'', EPOD of July 10, 2005. URL last accessed 2007-12-07.Pidwirny, M. URL last accessed 2007-12-07. Alternate names for needle ice are "frost pil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silt
Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension with water. Silt usually has a floury feel when dry, and lacks plasticity when wet. Silt also can be felt by the tongue as granular when placed on the front teeth (even when mixed with clay particles). Silt is a common material, making up 45% of average modern mud. It is found in many river deltas and as wind-deposited accumulations, particularly in central Asia, north China, and North America. It is produced in both very hot climates (through such processes as collisions of quartz grains in dust storms) and very cold climates (through such processes as glacial grinding of quartz grains.) Loess is soil rich in silt which makes up some of the most fertile agricultural land on Earth. However, silt is very vulnerable to erosion, and it has poor mechanical properties, making construction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snow Or Ice Weather Phenomena
Snow comprises individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water throughout its life cycle, starting when, under suitable conditions, the ice crystals form in the atmosphere, increase to millimeter size, precipitate and accumulate on surfaces, then metamorphose in place, and ultimately melt, slide or sublimate away. 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, which freeze in hexagonal-shaped crystals. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Spike
An ice spike is an ice formation, often in the shape of an inverted icicle, that projects upwards from the surface of a body of frozen water. Ice spikes created by natural processes on the surface of small bodies of frozen water have been reported for many decades, although their occurrence is quite rare. A mechanism for their formation, now known as the Bally–Dorsey model, was proposed in the early 20th century but this was not tested in the laboratory for many years. In recent years a number of photographs of natural ice spikes have appeared on the Internet as well as methods of producing them artificially by freezing distilled water in domestic refrigerators or freezers. This has allowed a small number of scientists to test the hypothesis in a laboratory setting and, although the experiments appear to confirm the validity of the Bally–Dorsey model, they have raised further questions about how natural ice spikes form, and more work remains to be done before the ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hair Ice
Hair ice, also known as ice wool or frost beard, is a type of ice that forms on dead wood and takes the shape of fine, silky hair. It is somewhat uncommon, and has been reported mostly at latitudes between 45 and 55 °N in broadleaf forests. The meteorologist (and discoverer of continental drift) Alfred Wegener described hair ice on wet dead wood in 1918,Alfred Wegener: ''Haareis auf morschem Holz.'' Die Naturwissenschaften 6/1, 1918. S. 598–601. assuming some specific fungi as the catalyst, a theory mostly confirmed by Gerhart Wagner and Christian Mätzler in 2005.Gerhart Wagner: Haareis – eine seltene winterliche Naturerscheinung. Was haben Pilze damit zu tun?' SZP/BSM 2005.Gerhart Wagner, Christian Mätzler: Haareis auf morschem Laubholz als biophysikalisches Phänomen.'' Forschungsbericht Nr. 2008-05-MW. Universität Bern. 2008.PDF-Download)Gerhart Wagner, Christian Mätzler: ''Haareis - Ein seltenes biophysikalisches Phänomen im Winter.'' Naturwissenschaftliche R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frost Flowers
A frost flower or ice flower is formed when thin layers of ice are extruded from long-stemmed plants in autumn or early winter. The thin layers of ice are often formed into exquisite patterns that curl into "petals" that resemble flowers. Types Frost flower formations are also referred to as ''frost faces'', ''ice castles'', ''ice blossoms'', or ''crystallofolia''. Types of frost flowers include needle ice, frost pillars or frost columns, extruded from pores in the soil, and ice ribbons, rabbit frost or rabbit ice, extruded from linear fissures in plant stems. The term "ice flower" is also used as synonym for ice ribbons, but it may be used to describe the unrelated phenomenon of window frost as well. Formation The formation of frost flowers is dependent on a freezing weather condition occurring when the ground is not already frozen. The sap in the stem of the plants will expand (water expands when frozen), causing long, thin cracks to form along the length of the stem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frost
Frost is a thin layer of ice on a solid surface, which forms from water vapor in an above- freezing atmosphere coming in contact with a solid surface whose temperature is below freezing, and resulting in a phase change from water vapor (a gas) to ice (a solid) as the water vapor reaches the freezing point. In temperate climates, it most commonly appears on surfaces near the ground as fragile white crystals; in cold climates, it occurs in a greater variety of forms. The propagation of crystal formation occurs by the process of nucleation. The ice crystals of frost form as the result of fractal process development. The depth of frost crystals varies depending on the amount of time they have been accumulating, and the concentration of the water vapor (humidity). Frost crystals may be invisible (black), clear (translucent), or white; if a mass of frost crystals scatters light in all directions, the coating of frost appears white. Types of frost include crystalline frost ( hoar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frost Heaving
Frost heaving (or a frost heave) is an upwards swelling of soil during freezing conditions caused by an increasing presence of ice as it grows towards the surface, upwards from the depth in the soil where freezing temperatures have penetrated into the soil (the freezing front or freezing boundary). Ice growth requires a water supply that delivers water to the freezing front via capillary action in certain soils. The weight of overlying soil restrains vertical growth of the ice and can promote the formation of lens-shaped areas of ice within the soil. Yet the force of one or more growing ice lenses is sufficient to lift a layer of soil, as much as or more. The soil through which water passes to feed the formation of ice lenses must be sufficiently porous to allow capillary action, yet not so porous as to break capillary continuity. Such soil is referred to as "frost susceptible". The growth of ice lenses continually consumes the rising water at the freezing front. Differential fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desiccation
Desiccation () is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic (attracts and holds water) substance that induces or sustains such a state in its local vicinity in a moderately sealed container. Industry Desiccation is widely employed in the oil and gas industry. These materials are obtained in a hydrated state, but the water content leads to corrosion or is incompatible with downstream processing. Removal of water is achieved by cryogenic condensation, absorption into glycols, and absorption onto desiccants such as silica gel. Laboratory A desiccator is a heavy glass or plastic container, now somewhat antiquated, used in practical chemistry for drying or keeping small amounts of materials very dry. The material is placed on a shelf, and a drying agent or ''desiccant'', such as dry silica gel or anhydrous sodium hydroxide, is placed below the shelf. Often some sort of humidity indicator is included in the desiccator to sho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seedling
A seedling is a young sporophyte developing out of a plant embryo from a seed. Seedling development starts with germination of the seed. A typical young seedling consists of three main parts: the radicle (embryonic root), the hypocotyl (embryonic shoot), and the cotyledons (seed leaves). The two classes of flowering plants (angiosperms) are distinguished by their numbers of seed leaves: monocotyledons (monocots) have one blade-shaped cotyledon, whereas dicotyledons (dicots) possess two round cotyledons. Gymnosperms are more varied. For example, pine seedlings have up to eight cotyledons. The seedlings of some flowering plants have no cotyledons at all. These are said to be acotyledons. The plumule is the part of a seed embryo that develops into the shoot bearing the first true leaves of a plant. In most seeds, for example the sunflower, the plumule is a small conical structure without any leaf structure. Growth of the plumule does not occur until the cotyledons have grown abov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Periglacial
Periglaciation (adjective: "periglacial", also referring to places at the edges of glacial areas) describes geomorphic processes that result from seasonal thawing of snow in areas of permafrost, the runoff from which refreezes in ice wedges and other structures. "Periglacial" suggests an environment located on the margin of past glaciers. However, freeze and thaw cycles influence landscapes outside areas of past glaciation. Therefore, periglacial environments are anywhere that freezing and thawing modify the landscape in a significant manner. Tundra is a common ecological community in periglacial areas. History Periglaciation became a distinct subject within the study of geology after Walery Łoziński, a Polish geologist, introduced the term in 1909. Łoziński drew upon the early work of Johan Gunnar Andersson. According to Alfred Jahn, his introduction of his work at the 1910 International Geological Congress held in Stockholm caused significant discussion. In the field trip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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