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85-630: King Edward VII Land or King Edward VII Peninsula is a large, ice -covered peninsula which forms the northwestern extremity of Marie Byrd Land in Antarctica . The peninsula projects into the Ross Sea between Sulzberger Bay and the northeast corner of the Ross Ice Shelf , and forms part of the Ross Dependency . Edward VII Peninsula is defined by the Ross Ice Shelf on the southwest, Okuma Bay on

170-480: A mineral . Depending on the presence of impurities such as particles of soil or bubbles of air , it can appear transparent or a more or less opaque bluish-white color. Virtually all of the ice on Earth is of a hexagonal crystalline structure denoted as ice I h (spoken as "ice one h"). Depending on temperature and pressure, at least nineteen phases ( packing geometries ) can exist. The most common phase transition to ice I h occurs when liquid water

255-619: A density between a quarter and two thirds that of pure ice, due to a high proportion of trapped air, which also makes soft rime appear white. Hard rime is denser, more transparent, and more likely to appear on ships and aircraft. Cold wind specifically causes what is known as advection frost when it collides with objects. When it occurs on plants, it often causes damage to them. Various methods exist to protect agricultural crops from frost - from simply covering them to using wind machines. In recent decades, irrigation sprinklers have been calibrated to spray just enough water to preemptively create

340-410: A few molecules in the droplet need to get together by chance to form an arrangement similar to that in an ice lattice; then the droplet freezes around this "nucleus". Experiments show that this "homogeneous" nucleation of cloud droplets only occurs at temperatures lower than −35 °C (238 K; −31 °F). In warmer clouds an aerosol particle or "ice nucleus" must be present in (or in contact with)

425-689: A form of precipitation consisting of small, translucent balls of ice, which are usually smaller than hailstones. This form of precipitation is also referred to as "sleet" by the United States National Weather Service . (In British English "sleet" refers to a mixture of rain and snow .) Ice pellets typically form alongside freezing rain, when a wet warm front ends up between colder and drier atmospheric layers. There, raindrops would both freeze and shrink in size due to evaporative cooling. So-called snow pellets, or graupel , form when multiple water droplets freeze onto snowflakes until

510-555: A function of temperature and sliding speed. 2014 research suggests that frictional heating is the most important process under most typical conditions. The term that collectively describes all of the parts of the Earth's surface where water is in frozen form is the cryosphere . Ice is an important component of the global climate, particularly in regard to the water cycle. Glaciers and snowpacks are an important storage mechanism for fresh water; over time, they may sublimate or melt. Snowmelt

595-432: A hailstone becomes too heavy to be supported by the storm's updraft, it falls from the cloud. Hail forms in strong thunderstorm clouds, particularly those with intense updrafts, high liquid water content, great vertical extent, large water droplets, and where a good portion of the cloud layer is below freezing 0 °C (32 °F). Hail-producing clouds are often identifiable by their green coloration. The growth rate

680-577: A key role in Earth's water cycle and climate . In the recent decades, ice volume on Earth has been decreasing due to climate change . The largest declines have occurred in the Arctic and in the mountains located outside of the polar regions. The loss of grounded ice (as opposed to floating sea ice ) is the primary contributor to sea level rise . Humans have been using ice for various purposes for thousands of years. Some historic structures designed to hold ice to provide cooling are over 2,000 years old. Before

765-419: A layer of ice that would form slowly and so avoid a sudden temperature shock to the plant, and not be so thick as to cause damage with its weight. Ablation of ice refers to both its melting and its dissolution . The melting of ice entails the breaking of hydrogen bonds between the water molecules. The ordering of the molecules in the solid breaks down to a less ordered state and the solid melts to become

850-456: A liquid. This is achieved by increasing the internal energy of the ice beyond the melting point . When ice melts it absorbs as much energy as would be required to heat an equivalent amount of water by 80 °C. While melting, the temperature of the ice surface remains constant at 0 °C. The rate of the melting process depends on the efficiency of the energy exchange process. An ice surface in fresh water melts solely by free convection with

935-436: A low speed. Ice forms on calm water from the shores, a thin layer spreading across the surface, and then downward. Ice on lakes is generally four types: primary, secondary, superimposed and agglomerate. Primary ice forms first. Secondary ice forms below the primary ice in a direction parallel to the direction of the heat flow. Superimposed ice forms on top of the ice surface from rain or water which seeps up through cracks in

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1020-453: A man who works as a blacksmith plunges a screaming great axe blade or adze into cold water, treating it for temper, since this is the way steel is made strong, even so Cyclops' eye sizzled about the beam of the olive. However, it is not beyond doubt that the passage describes deliberate quench-hardening, rather than simply cooling. Likewise, there is a prospect that the Mahabharata refers to

1105-463: A much harder structure known as martensite. Steels with this martensitic structure are often used in applications when the workpiece must be highly resistant to deformation, such as the cutting edge of blades. This is very efficient. The process of quenching is a progression, beginning with heating the sample. Most materials are heated to between 815 and 900 °C (1,499 and 1,652 °F), with careful attention paid to keeping temperatures throughout

1190-707: A party of the Japanese Antarctic Expedition led by Shirase Nobu in 1912. The region was renamed "Edward VII Peninsula" after the peninsular character of the region was determined by exploration conducted by the Byrd Antarctic Expedition (1933–1935) and the United States Antarctic Service (USAS) Expedition (1939–1941). Most of the peninsula is within the Ross Dependency , claimed by New Zealand (see Territorial claims of Antarctica ). This Ross Dependency location article

1275-505: A rate that depends linearly on the water temperature, T ∞ , when T ∞ is less than 3.98 °C, and superlinearly when T ∞ is equal to or greater than 3.98 °C, with the rate being proportional to (T ∞  − 3.98 °C) , with α  =  ⁠ 5 / 3 ⁠ for T ∞ much greater than 8 °C, and α =  ⁠ 4 / 3 ⁠ for in between temperatures T ∞ . In salty ambient conditions, dissolution rather than melting often causes

1360-487: A single oxygen atom covalently bonded to two hydrogen atoms , or H–O–H. However, many of the physical properties of water and ice are controlled by the formation of hydrogen bonds between adjacent oxygen and hydrogen atoms; while it is a weak bond, it is nonetheless critical in controlling the structure of both water and ice. An unusual property of water is that its solid form—ice frozen at atmospheric pressure —is approximately 8.3% less dense than its liquid form; this

1445-746: A soft ball-like shape is formed. So-called " diamond dust ", (METAR code IC ) also known as ice needles or ice crystals, forms at temperatures approaching −40 °C (−40 °F) due to air with slightly higher moisture from aloft mixing with colder, surface-based air. As water drips and re-freezes, it can form hanging icicles , or stalagmite -like structures on the ground. On sloped roofs, buildup of ice can produce an ice dam , which stops melt water from draining properly and potentially leads to damaging leaks. More generally, water vapor depositing onto surfaces due to high relative humidity and then freezing results in various forms of atmospheric icing , or frost . Inside buildings, this can be seen as ice on

1530-488: A substance with an inverse solubility that therefore deposits on the object to slow the rate of cooling. Quenching can also be accomplished using inert gases, such as nitrogen and noble gases. Nitrogen is commonly used at greater than atmospheric pressure ranging up to 20 bar absolute. Helium is also used because its thermal capacity is greater than nitrogen. Alternatively, argon can be used; however, its density requires significantly more energy to move, and its thermal capacity

1615-471: A temperature of −78.5 °C (−109.3 °F), the vaporization point of solid carbon dioxide (dry ice). Most liquids under increased pressure freeze at higher temperatures because the pressure helps to hold the molecules together. However, the strong hydrogen bonds in water make it different: for some pressures higher than 1 atm (0.10 MPa), water freezes at a temperature below 0 °C (32 °F). Ice, water, and water vapour can coexist at

1700-574: A thin surface layer, which makes it particularly hazardous to walk across it. Another dangerous form of rotten ice to traverse on foot is candle ice, which develops in columns perpendicular to the surface of a lake. Because it lacks a firm horizontal structure, a person who has fallen through has nothing to hold onto to pull themselves out. Snow crystals form when tiny supercooled cloud droplets (about 10  μm in diameter) freeze . These droplets are able to remain liquid at temperatures lower than −18 °C (255 K; 0 °F), because to freeze,

1785-454: A uniform and lamellar (or layered) pearlitic grain structure. This is a mixture of ferrite and cementite formed when steel or cast iron are manufactured and cooled at a slow rate. Pearlite is not an ideal material for many common applications of steel alloys as it is quite soft. By heating pearlite past its eutectoid transition temperature of 727 °C and then rapidly cooling, some of the material's crystal structure can be transformed into

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1870-458: Is a stub . You can help Misplaced Pages by expanding it . Ice Ice is water that is frozen into a solid state, typically forming at or below temperatures of 0 ° C , 32 ° F , or 273.15 K . It occurs naturally on Earth , on other planets, in Oort cloud objects, and as interstellar ice . As a naturally occurring crystalline inorganic solid with an ordered structure, ice is considered to be

1955-442: Is a basic cause of freeze-thaw weathering of rock in nature and damage to building foundations and roadways from frost heaving . 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. Because ice is less dense than liquid water, it floats, and this prevents bottom-up freezing of the bodies of water. Instead, a sheltered environment for animal and plant life

2040-427: Is abundant on the Earth's surface, particularly in the polar regions and above the snow line , where it can aggregate from snow to form glaciers and ice sheets . As snowflakes and hail , ice is a common form of precipitation , and it may also be deposited directly by water vapor as frost . The transition from ice to water is melting and from ice directly to water vapor is sublimation . These processes plays

2125-424: Is an important source of seasonal fresh water. The World Meteorological Organization defines several kinds of ice depending on origin, size, shape, influence and so on. Clathrate hydrates are forms of ice that contain gas molecules trapped within its crystal lattice. Ice that is found at sea may be in the form of drift ice floating in the water, fast ice fixed to a shoreline or anchor ice if attached to

2210-524: Is below the boiling point of the liquid. There is evidence of the use of quenching processes by blacksmiths stretching back into the middle of the Iron Age , but little detailed information exists related to the development of these techniques and the procedures employed by early smiths. Although early ironworkers must have swiftly noticed that processes of cooling could affect the strength and brittleness of iron, and it can be claimed that heat treatment of steel

2295-498: Is cooled below 0  °C ( 273.15  K , 32  °F ) at standard atmospheric pressure . When water is cooled rapidly ( quenching ), up to three types of amorphous ice can form. Interstellar ice is overwhelmingly low-density amorphous ice (LDA), which likely makes LDA ice the most abundant type in the universe. When cooled slowly, correlated proton tunneling occurs below −253.15  °C ( 20  K , −423.67  °F ) giving rise to macroscopic quantum phenomena . Ice

2380-420: Is desired, but there is a small chance that it may cause distortion and tiny cracking. When hardness can be sacrificed, mineral oils are often used. These oil-based fluids often oxidize and form sludge during quenching, which consequently lowers the efficiency of the process. The cooling rate of oil is much less than water. Intermediate rates between water and oil can be obtained with a purpose-formulated quenchant,

2465-490: Is divided into four categories: pore ice, vein ice (also known as ice wedges), buried surface ice and intrasedimental ice (from the freezing of underground waters). One example of ice formation in permafrost areas is aufeis - layered ice that forms in Arctic and subarctic stream valleys. Ice, frozen in the stream bed, blocks normal groundwater discharge, and causes the local water table to rise, resulting in water discharge on top of

2550-450: Is done by heating the material to a certain temperature, depending on the material. This produces a harder material by either surface hardening or through-hardening varying on the rate at which the material is cooled. The material is then often tempered to reduce the brittleness that may increase from the quench hardening process. Items that may be quenched include gears, shafts, and wear blocks. Before hardening, cast steels and iron are of

2635-435: Is equivalent to a volumetric expansion of 9%. The density of ice is 0.9167 –0.9168  g/cm at 0 °C and standard atmospheric pressure (101,325 Pa), whereas water has a density of 0.9998 –0.999863  g/cm at the same temperature and pressure. Liquid water is densest, essentially 1.00 g/cm , at 4 °C and begins to lose its density as the water molecules begin to form the hexagonal crystals of ice as

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2720-484: Is extremely rare otherwise. Even icy moons like Ganymede are expected to mainly consist of other crystalline forms of ice. Water in the interstellar medium is dominated by amorphous ice, making it likely the most common form of water in the universe. Low-density ASW (LDA), also known as hyperquenched glassy water, may be responsible for noctilucent clouds on Earth and is usually formed by deposition of water vapor in cold or vacuum conditions. High-density ASW (HDA)

2805-484: Is formed beneath the floating ice, which protects the underside from short-term weather extremes such as wind chill . Sufficiently thin floating ice allows light to pass through, supporting the photosynthesis of bacterial and algal colonies. When sea water freezes, the ice is riddled with brine-filled channels which sustain sympagic organisms such as bacteria, algae, copepods and annelids . In turn, they provide food for animals such as krill and specialized fish like

2890-452: Is formed by compression of ordinary ice I h or LDA at GPa pressures. Very-high-density ASW (VHDA) is HDA slightly warmed to 160 K under 1–2 GPa pressures. Ice from a theorized superionic water may possess two crystalline structures. At pressures in excess of 500,000 bars (7,300,000 psi) such superionic ice would take on a body-centered cubic structure. However, at pressures in excess of 1,000,000 bars (15,000,000 psi)

2975-433: Is important that the temperature throughout the sample remains as uniform as possible during soaking. Once the workpiece has finished soaking, it moves on to the cooling step. During this step, the part is submerged into some kind of quenching fluid; different quenching fluids can have a significant effect on the final characteristics of a quenched part. Water is one of the most efficient quenching media where maximum hardness

3060-455: Is less than the alternatives. To minimize distortion in the workpiece, long cylindrical workpieces are quenched vertically; flat workpieces are quenched on the edge; and thick sections should enter the bath first. To prevent steam bubbles the bath is agitated. Often, after quenching, an iron or steel alloy will be excessively hard and brittle due to an overabundance of martensite. In these cases, another heat treatment technique known as tempering

3145-448: Is maximized at about −13 °C (9 °F), and becomes vanishingly small much below −30 °C (−22 °F) as supercooled water droplets become rare. For this reason, hail is most common within continental interiors of the mid-latitudes, as hail formation is considerably more likely when the freezing level is below the altitude of 11,000 feet (3,400 m). Entrainment of dry air into strong thunderstorms over continents can increase

3230-401: Is most commonly used to harden steel by inducing a martensite transformation, where the steel must be rapidly cooled through its eutectoid point, the temperature at which austenite becomes unstable. Rapid cooling prevents the formation of cementite structure, instead forcibly dissolving carbon atoms in the ferrite lattice. In steel alloyed with metals such as nickel and manganese ,

3315-464: Is over 70% ice on its surface is said to be covered by pack ice. Fully formed sea ice can be forced together by currents and winds to form pressure ridges up to 12 metres (39 ft) tall. On the other hand, active wave activity can reduce sea ice to small, regularly shaped pieces, known as pancake ice . Sometimes, wind and wave activity "polishes" sea ice to perfectly spherical pieces known as ice eggs . The largest ice formations on Earth are

3400-469: Is performed on the quenched material to increase the toughness of iron -based alloys . Tempering is usually performed after hardening , to reduce some of the excess hardness , and is done by heating the metal to some temperature below the critical point for a certain period of time, then allowing it to cool in still air. Heat is removed in three particular stages: Stage A: Vapor bubbles formed over metal and starts cooling During this stage, due to

3485-409: Is shifted toward slightly lower energies. Thus, ice appears blue, with a slightly greener tint than liquid water. Since absorption is cumulative, the color effect intensifies with increasing thickness or if internal reflections cause the light to take a longer path through the ice. Other colors can appear in the presence of light absorbing impurities, where the impurity is dictating the color rather than

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3570-531: Is therefore slower than melting. Ice has long been valued as a means of cooling. In 400 BC Iran, Persian engineers had already developed techniques for ice storage in the desert through the summer months. During the winter, ice was transported from harvesting pools and nearby mountains in large quantities to be stored in specially designed, naturally cooled refrigerators , called yakhchal (meaning ice storage ). Yakhchals were large underground spaces (up to 5000 m ) that had thick walls (at least two meters at

3655-462: The Leidenfrost effect , the object is fully surrounded by vapor which insulates it from the rest of the liquid. Stage B: Vapor-transport cooling Once the temperature has dropped enough, the vapor layer will destabilize and the liquid will be able to fully contact the object and heat will be removed much more quickly. Stage C: Liquid cooling This stage occurs when the temperature of the object

3740-660: The Swinburne Ice Shelf is located. Edward VII Peninsula was discovered on 30 January 1902 by the British National Antarctic Expedition (BrNAE) (1901–1904) under Robert Falcon Scott , who named it King Edward VII Land for King Edward VII of the United Kingdom . The coastline was further explored by the Nimrod Expedition under Ernest Shackleton in 1908–09, and the first landfall was made by

3825-446: The bald notothen , fed upon in turn by larger animals such as emperor penguins and minke whales . When ice melts, it absorbs as much energy as it would take to heat an equivalent mass of water by 80 °C (176 °F). During the melting process, the temperature remains constant at 0 °C (32 °F). While melting, any energy added breaks the hydrogen bonds between ice (water) molecules. Energy becomes available to increase

3910-752: The triple point , which is exactly 273.16 K (0.01 °C) at a pressure of 611.657  Pa . The kelvin was defined as ⁠ 1 / 273.16 ⁠ of the difference between this triple point and absolute zero , though this definition changed in May 2019. Unlike most other solids, ice is difficult to superheat . In an experiment, ice at −3 °C was superheated to about 17 °C for about 250 picoseconds . Subjected to higher pressures and varying temperatures, ice can form in nineteen separate known crystalline phases at various densities, along with hypothetical proposed phases of ice that have not been observed. With care, at least fifteen of these phases (one of

3995-473: The "Ice King", worked on developing better insulation products for long distance shipments of ice, especially to the tropics; this became known as the ice trade. Between 1812 and 1822, under Lloyd Hesketh Bamford Hesketh 's instruction, Gwrych Castle was built with 18 large towers, one of those towers is called the 'Ice Tower'. Its sole purpose was to store Ice. Trieste sent ice to Egypt , Corfu , and Zante ; Switzerland, to France; and Germany sometimes

4080-621: The United States, with a combined value of shipments of $ 595,487,000. Home refrigerators can also make ice with a built in icemaker , which will typically make ice cubes or crushed ice. The first such device was presented in 1965 by Frigidaire . Ice forming on roads is a common winter hazard, and black ice particularly dangerous because it is very difficult to see. It is both very transparent, and often forms specifically in shaded (and therefore cooler and darker) areas, i.e. beneath overpasses . Quenching In metallurgy , quenching

4165-469: The ablation of ice. For example, the temperature of the Arctic Ocean is generally below the melting point of ablating sea ice. The phase transition from solid to liquid is achieved by mixing salt and water molecules, similar to the dissolution of sugar in water, even though the water temperature is far below the melting point of the sugar. However, the dissolution rate is limited by salt concentration and

4250-431: The air has most of the desired effects of quenching; high-speed steel weakens much less from heat cycling due to high-speed cutting. Extremely rapid cooling can prevent the formation of all crystal structures, resulting in amorphous metal or "metallic glass". Quench hardening is a mechanical process in which steel and cast iron alloys are strengthened and hardened. These metals consist of ferrous metals and alloys. This

4335-419: The base) made of a specific type of mortar called sarooj made from sand, clay, egg whites, lime, goat hair, and ash. The mortar was resistant to heat transfer, helping to keep the ice cool enough not to melt; it was also impenetrable by water. Yakhchals often included a qanat and a system of windcatchers that could lower internal temperatures to frigid levels, even during the heat of the summer. One use for

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4420-427: The droplet to act as a nucleus. Our understanding of what particles make efficient ice nuclei is poor – what we do know is they are very rare compared to that cloud condensation nuclei on which liquid droplets form. Clays, desert dust and biological particles may be effective, although to what extent is unclear. Artificial nuclei are used in cloud seeding . The droplet then grows by condensation of water vapor onto

4505-481: The eutectoid temperature becomes much lower, but the kinetic barriers to phase transformation remain the same. This allows quenching to start at a lower temperature, making the process much easier. High-speed steel also has added tungsten , which serves to raise kinetic barriers, which, among other effects, gives material properties (hardness and abrasion resistance) as though the workpiece had been cooled more rapidly than it really has. Even cooling such alloys slowly in

4590-449: 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. The density of ice increases slightly with decreasing temperature and has a value of 0.9340 g/cm at −180 °C (93 K). When water freezes, it increases in volume (about 9% for fresh water). The effect of expansion during freezing can be dramatic, and ice expansion

4675-465: The frequency of hail by promoting evaporative cooling which lowers the freezing level of thunderstorm clouds giving hail a larger volume to grow in. Accordingly, hail is actually less common in the tropics despite a much higher frequency of thunderstorms than in the mid-latitudes because the atmosphere over the tropics tends to be warmer over a much greater depth. Hail in the tropics occurs mainly at higher elevations. Ice pellets ( METAR code PL ) are

4760-534: The frozen layer. This water then freezes, causing the water table to rise further and repeat the cycle. The result is a stratified ice deposit, often several meters thick. Snow line and snow fields are two related concepts, in that snow fields accumulate on top of and ablate away to the equilibrium point (the snow line) in an ice deposit. Ice which forms on moving water tends to be less uniform and stable than ice which forms on calm water. Ice jams (sometimes called "ice dams"), when broken chunks of ice pile up, are

4845-636: The greatest ice hazard on rivers. Ice jams can cause flooding, damage structures in or near the river, and damage vessels on the river. Ice jams can cause some hydropower industrial facilities to completely shut down. An ice dam is a blockage from the movement of a glacier which may produce a proglacial lake . Heavy ice flows in rivers can also damage vessels and require the use of an icebreaker vessel to keep navigation possible. Ice discs are circular formations of ice floating on river water. They form within eddy currents , and their position results in asymmetric melting, which makes them continuously rotate at

4930-499: The hailstones to the upper part of the cloud. The updraft dissipates and the hailstones fall down, back into the updraft, and are lifted up again. Hail has a diameter of 5 millimetres (0.20 in) or more. Within METAR code, GR is used to indicate larger hail, of a diameter of at least 6.4 millimetres (0.25 in) and GS for smaller. Stones of 19 millimetres (0.75 in), 25 millimetres (1.0 in) and 44 millimetres (1.75 in) are

5015-464: The ice exerted by any object. However, the significance of this hypothesis is disputed by experiments showing a high coefficient of friction for ice using atomic force microscopy . Thus, the mechanism controlling the frictional properties of ice is still an active area of scientific study. A comprehensive theory of ice friction must take into account all of the aforementioned mechanisms to estimate friction coefficient of ice against various materials as

5100-429: The ice itself. For instance, icebergs containing impurities (e.g., sediments, algae, air bubbles) can appear brown, grey or green. Because ice in natural environments is usually close to its melting temperature, its hardness shows pronounced temperature variations. At its melting point, ice has a Mohs hardness of 2 or less, but the hardness increases to about 4 at a temperature of −44 °C (−47 °F) and to 6 at

5185-456: The ice layer is caused by friction. However, this theory does not sufficiently explain why ice is slippery when standing still even at below-zero temperatures. Subsequent research suggested that ice molecules at the interface cannot properly bond with the molecules of the mass of ice beneath (and thus are free to move like molecules of liquid water). These molecules remain in a semi-liquid state, providing lubrication regardless of pressure against

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5270-471: The ice surfaces. Ice storm is a type of winter storm characterized by freezing rain , which produces a glaze of ice on surfaces, including roads and power lines . In the United States, a quarter of winter weather events produce glaze ice, and utilities need to be prepared to minimize damages. Hail forms in storm clouds when supercooled water droplets freeze on contact with condensation nuclei , such as dust or dirt . The storm's updraft blows

5355-474: The ice was to create chilled treats for royalty. There were thriving industries in 16th–17th century England whereby low-lying areas along the Thames Estuary were flooded during the winter, and ice harvested in carts and stored inter-seasonally in insulated wooden houses as a provision to an icehouse often located in large country houses, and widely used to keep fish fresh when caught in distant waters. This

5440-416: The ice which often settles when loaded with snow. An ice shove occurs when ice movement, caused by ice expansion and/or wind action, occurs to the extent that ice pushes onto the shores of lakes, often displacing sediment that makes up the shoreline. Shelf ice is formed when floating pieces of ice are driven by the wind piling up on the windward shore. This kind of ice may contain large air pockets under

5525-603: The ice, would melt a thin layer, providing sufficient lubrication for the blade to glide across the ice. Yet, 1939 research by Frank P. Bowden and T. P. Hughes found that skaters would experience a lot more friction than they actually do if it were the only explanation. Further, the optimum temperature for figure skating is −5.5 °C (22 °F; 268 K) and −9 °C (16 °F; 264 K) for hockey; yet, according to pressure melting theory, skating below −4 °C (25 °F; 269 K) would be outright impossible. Instead, Bowden and Hughes argued that heating and melting of

5610-427: The invention of refrigeration technology, the only way to safely store food without modifying it through preservatives was to use ice. Sufficiently solid surface ice makes waterways accessible to land transport during winter, and dedicated ice roads may be maintained. Ice also plays a major role in winter sports . Ice possesses a regular crystalline structure based on the molecule of water, which consists of

5695-515: The known exceptions being ice X) can be recovered at ambient pressure and low temperature in metastable form. The types are differentiated by their crystalline structure, proton ordering, and density. There are also two metastable phases of ice under pressure, both fully hydrogen-disordered; these are Ice IV and Ice XII. Ice XII was discovered in 1996. In 2006, Ice XIII and Ice XIV were discovered. Ices XI, XIII, and XIV are hydrogen-ordered forms of ices I h , V, and XII respectively. In 2009, ice XV

5780-495: The large number of glaciers it contains. They cover an area of around 80,000 km (31,000 sq mi), and have a combined volume of between 3,000-4,700 km . These glaciers are nicknamed "Asian water towers", because their meltwater run-off feeds into rivers which provide water for an estimated two billion people. Permafrost refers to soil or underwater sediment which continuously remains below 0 °C (32 °F) for two years or more. The ice within permafrost

5865-517: The most frequently reported hail sizes in North America. Hailstones can grow to 15 centimetres (6 in) and weigh more than 0.5 kilograms (1.1 lb). In large hailstones, latent heat released by further freezing may melt the outer shell of the hailstone. The hailstone then may undergo 'wet growth', where the liquid outer shell collects other smaller hailstones. The hailstone gains an ice layer and grows increasingly larger with each ascent. Once

5950-478: The oil-quenching of iron arrowheads, but the evidence is problematic. Pliny the Elder addressed the topic of quenchants, distinguishing the water of different rivers. Chapters 18-21 of the twelfth-century De diversis artis by Theophilus Presbyter mentions quenching, recommending amongst other things that 'tools are also given a harder tempering in the urine of a small, red-headed boy than in ordinary water'. One of

6035-514: The process to an even older author, Ibn Bakhtawayhi, of whom nothing is known. Ice is now produced on an industrial scale, for uses including food storage and processing, chemical manufacturing, concrete mixing and curing, and consumer or packaged ice. Most commercial icemakers produce three basic types of fragmentary ice: flake, tubular and plate, using a variety of techniques. Large batch ice makers can produce up to 75 tons of ice per day. In 2002, there were 426 commercial ice-making companies in

6120-481: The quenching is slower or interrupted, which also allows pearlite to form and results in a less brittle product. The earliest examples of quenched steel may come from ancient Mesopotamia, with a relatively secure example of a fourth-century BC quench-hardened chisel from Al Mina in Turkey. Book 9, lines 389-94 of Homer's Odyssey is widely cited as an early, possibly the first, written reference to quenching: as when

6205-425: The seafloor. Ice which calves (breaks off) from an ice shelf or a coastal glacier may become an iceberg. The aftermath of calving events produces a loose mixture of snow and ice known as Ice mélange . Sea ice forms in several stages. At first, small, millimeter-scale crystals accumulate on the water surface in what is known as frazil ice . As they become somewhat larger and more consistent in shape and cover,

6290-440: The structure may shift to a more stable face-centered cubic lattice. It is speculated that superionic ice could compose the interior of ice giants such as Uranus and Neptune. Ice is " slippery " because it has a low coefficient of friction. This subject was first scientifically investigated in the 19th century. The preferred explanation at the time was " pressure melting " -i.e. the blade of an ice skate, upon exerting pressure on

6375-688: The summer. The advent of artificial refrigeration technology made the delivery of ice obsolete. Ice is still harvested for ice and snow sculpture events . For example, a swing saw is used to get ice for the Harbin International Ice and Snow Sculpture Festival each year from the frozen surface of the Songhua River . The earliest known written process to artificially make ice is by the 13th-century writings of Arab historian Ibn Abu Usaybia in his book Kitab Uyun al-anba fi tabaqat-al-atibba concerning medicine in which Ibn Abu Usaybia attributes

6460-443: The surface of un-insulated windows. Hoar frost is common in the environment, particularly in the low-lying areas such as valleys . In Antarctica, the temperatures can be so low that electrostatic attraction is increased to the point hoarfrost on snow sticks together when blown by wind into tumbleweed -like balls known as yukimarimo . Sometimes, drops of water crystallize on cold objects as rime instead of glaze. Soft rime has

6545-441: The thermal energy (temperature) 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 . As with water, ice absorbs light at the red end of the spectrum preferentially as the result of an overtone of an oxygen–hydrogen (O–H) bond stretch. Compared with water, this absorption

6630-480: The two ice sheets which almost completely cover the world's largest island, Greenland , and the continent of Antarctica . These ice sheets have an average thickness of over 1 km (0.6 mi) and have existed for millions of years. Other major ice formations on land include ice caps , ice fields , ice streams and glaciers . In particular, the Hindu Kush region is known as the Earth's "Third Pole" due to

6715-433: The water surface begins to look "oily" from above, so this stage is called grease ice . Then, ice continues to clump together, and solidify into flat cohesive pieces known as ice floes . Ice floes are the basic building blocks of sea ice cover, and their horizontal size (defined as half of their diameter ) varies dramatically, with the smallest measured in centimeters and the largest in hundreds of kilometers. An area which

6800-457: The west, and to the east by Sulzberger Bay and the Saunders Coast , all essentially on the Ross Sea / Southern Ocean in Antarctica . The northwest extremity of the peninsula is Cape Colbeck . Edward VII Peninsula is located at 77°40′S 155°00′W  /  77.667°S 155.000°W  / -77.667; -155.000 . The western coast is Shirase Coast . In the north and east

6885-401: The workpiece uniform. Minimizing uneven heating and overheating is key to imparting desired material properties. The second step in the quenching process is soaking. Workpieces can be soaked in air (air furnace), a liquid bath, or a vacuum. The recommended time allocation in salt or lead baths is up to 6 minutes. Soaking times can range a little higher within a vacuum. As in the heating step, it

6970-452: Was allegedly copied by an Englishman who had seen the same activity in China. Ice was imported into England from Norway on a considerable scale as early as 1823. In the United States, the first cargo of ice was sent from New York City to Charleston, South Carolina , in 1799, and by the first half of the 19th century, ice harvesting had become a big business. Frederic Tudor , who became known as

7055-411: Was found at extremely high pressures and −143 °C. At even higher pressures, ice is predicted to become a metal ; this has been variously estimated to occur at 1.55 TPa or 5.62 TPa. As well as crystalline forms, solid water can exist in amorphous states as amorphous solid water (ASW) of varying densities. In outer space, hexagonal crystalline ice is present in the ice volcanoes , but

7140-529: Was known in the Old World from the late second millennium BC, it is hard to identify deliberate uses of quenching archaeologically. Moreover, it appears that, at least in Europe, "quenching and tempering separately do not seem to have become common until the 15th century"; it is helpful to distinguish between "full quenching" of steel, where the quenching is so rapid that only martensite forms, and "slack quenching", where

7225-500: Was supplied from Bavarian lakes. From 1930s and up until 1994, the Hungarian Parliament building used ice harvested in the winter from Lake Balaton for air conditioning. Ice houses were used to store ice formed in the winter, to make ice available all year long, and an early type of refrigerator known as an icebox was cooled using a block of ice placed inside it. Many cities had a regular ice delivery service during

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