Contenu de sensagent
Dictionnaire et traducteur pour mobile
Nouveau : sensagent est maintenant disponible sur votre mobile
dictionnaire et traducteur pour sites web
Une fenêtre (pop-into) d'information (contenu principal de Sensagent) est invoquée un double-clic sur n'importe quel mot de votre page web. LA fenêtre fournit des explications et des traductions contextuelles, c'est-à-dire sans obliger votre visiteur à quitter votre page web !
Avec la boîte de recherches Sensagent, les visiteurs de votre site peuvent également accéder à une information de référence pertinente parmi plus de 5 millions de pages web indexées sur Sensagent.com. Vous pouvez Choisir la taille qui convient le mieux à votre site et adapter la charte graphique.
Solution commerce électronique
Augmenter le contenu de votre site
Ajouter de nouveaux contenus Add à votre site depuis Sensagent par XML.
Parcourir les produits et les annonces
Obtenir des informations en XML pour filtrer le meilleur contenu.
Indexer des images et définir des méta-données
Fixer la signification de chaque méta-donnée (multilingue).
Renseignements suite à un email de description de votre projet.
Jeux de lettres
Lettris est un jeu de lettres gravitationnelles proche de Tetris. Chaque lettre qui apparaît descend ; il faut placer les lettres de telle manière que des mots se forment (gauche, droit, haut et bas) et que de la place soit libérée.
Il s'agit en 3 minutes de trouver le plus grand nombre de mots possibles de trois lettres et plus dans une grille de 16 lettres. Il est aussi possible de jouer avec la grille de 25 cases. Les lettres doivent être adjacentes et les mots les plus longs sont les meilleurs. Participer au concours et enregistrer votre nom dans la liste de meilleurs joueurs ! Jouer
Dictionnaire de la langue française
La plupart des définitions du français sont proposées par SenseGates et comportent un approfondissement avec Littré et plusieurs auteurs techniques spécialisés.
Le dictionnaire des synonymes est surtout dérivé du dictionnaire intégral (TID).
L'encyclopédie française bénéficie de la licence Wikipedia (GNU).
Les jeux de lettres anagramme, mot-croisé, joker, Lettris et Boggle sont proposés par Memodata.
Le service web Alexandria est motorisé par Memodata pour faciliter les recherches sur Ebay. La SensagentBox est offerte par sensAgent.
Changer la langue cible pour obtenir des traductions.
Astuce: parcourir les champs sémantiques du dictionnaire analogique en plusieurs langues pour mieux apprendre avec sensagent.
1.a rink with a floor of ice for ice hockey or ice skating"the crowd applauded when she skated out onto the ice"
2.an amphetamine derivative (trade name Methedrine) used in the form of a crystalline hydrochloride; used as a stimulant to the nervous system and as an appetite suppressant
3.a frozen dessert with fruit flavoring (especially one containing no milk)
4.a flavored sugar topping used to coat and decorate cakes
5.the frozen part of a body of water
6.diamonds"look at the ice on that dame!"
7.water frozen in the solid state"Americans like ice in their drinks"
8.frozen dessert containing cream and sugar and flavoring
9.an ice containing milk
1.a heat engine in which combustion occurs inside the engine rather than in a separate furnace; heat expands a gas that either moves a piston or turns a gas turbine
1.put ice on or put on ice"Ice your sprained limbs"
2.decorate with frosting"frost a cake"
3.make cool or cooler"Chill the food"
4.cause to become ice or icy"an iced summer drink"
IceIce (īs), n. [OE. is, iis, AS. īs; aksin to D. ijs, G. eis, OHG. īs, Icel. īss, Sw. is, Dan. iis, and perh. to E. iron.]
1. Water or other fluid frozen or reduced to the solid state by cold; frozen water. It is a white or transparent colorless substance, crystalline, brittle, and viscoidal. Its specific gravity (0.92, that of water at 4° C. being 1.0) being less than that of water, ice floats.
☞ Water freezes at 32° F. or 0° Cent., and ice melts at the same temperature. Ice owes its cooling properties to the large amount of heat required to melt it.
2. Concreted sugar. Johnson.
3. Water, cream, custard, etc., sweetened, flavored, and artificially frozen.
4. Any substance having the appearance of ice; as, camphor ice.
Anchor ice, ice which sometimes forms about stones and other objects at the bottom of running or other water, and is thus attached or anchored to the ground. -- Bay ice, ice formed in bays, fiords, etc., often in extensive fields which drift out to sea. -- Ground ice, anchor ice. -- Ice age (Geol.), the glacial epoch or period. See under Glacial. -- Ice anchor (Naut.), a grapnel for mooring a vessel to a field of ice. Kane. -- Ice blink [Dan. iisblink], a streak of whiteness of the horizon, caused by the reflection of light from ice not yet in sight. -- Ice boat. (a) A boat fitted with skates or runners, and propelled on ice by sails; an ice yacht. (b) A strong steamboat for breaking a channel through ice. -- Ice box or Ice chest, a box for holding ice; a box in which things are kept cool by means of ice; a refrigerator. -- Ice brook, a brook or stream as cold as ice. [Poetic] Shak. -- Ice cream [for iced cream], cream, milk, or custard, sweetened, flavored, and frozen. -- Ice field, an extensive sheet of ice. -- Ice float, Ice floe, a sheet of floating ice similar to an ice field, but smaller. -- Ice foot, shore ice in Arctic regions; an ice belt. Kane. -- Ice house, a close-covered pit or building for storing ice. -- Ice machine (Physics), a machine for making ice artificially, as by the production of a low temperature through the sudden expansion of a gas or vapor, or the rapid evaporation of a volatile liquid. -- Ice master. See Ice pilot (below). -- Ice pack, an irregular mass of broken and drifting ice. -- Ice paper, a transparent film of gelatin for copying or reproducing; papier glacé. -- Ice petrel (Zoöl.), a shearwater (Puffinus gelidus) of the Antarctic seas, abundant among floating ice. -- Ice pick, a sharp instrument for breaking ice into small pieces. -- Ice pilot, a pilot who has charge of a vessel where the course is obstructed by ice, as in polar seas; -- called also ice master. -- Ice pitcher, a pitcher adapted for ice water. -- Ice plow, a large tool for grooving and cutting ice. -- Ice sludge, bay ice broken small by the wind or waves; sludge. -- Ice spar (Min.), a variety of feldspar, the crystals of which are very clear like ice; rhyacolite. -- Ice tongs, large iron nippers for handling ice. -- Ice water. (a) Water cooled by ice. (b) Water formed by the melting of ice. -- Ice yacht. See Ice boat (above). -- To break the ice. See under Break. -- Water ice, a confection consisting of water sweetened, flavored (usually with a fruit syrup), and frozen.
IceIce (īs), v. t. [imp. & p. p. Iced (īst); p. pr. & vb. n. Icing (ī"sĭng).]
1. To cover with ice; to convert into ice, or into something resembling ice.
2. To cover with icing, or frosting made of sugar and milk or white of egg; to frost, as cakes, tarts, etc.
3. To chill or cool, as with ice; to freeze.
chalk, chicken feed, crank, deoxyephedrine, frappe, freezing rain, frost, frosting, glass, icecream, ice cream, ice-cream, ice lolly, ice-skating rink, icing, meth, methamphetamine, methamphetamine hydrochloride, Methedrine, popsicle, shabu, sherbert, sorbet, sparkler, trash, water ice, ice rink (sport), rink (sport), sherbet (American), skating rink (sport)
Dry Ice • Fall involving ice-skates, skis, roller-skates or skateboards • Fall involving ice-skates, skis, roller-skates or skateboards | farm • Fall involving ice-skates, skis, roller-skates or skateboards | home • Fall involving ice-skates, skis, roller-skates or skateboards | industrial and construction area • Fall involving ice-skates, skis, roller-skates or skateboards | other specified places • Fall involving ice-skates, skis, roller-skates or skateboards | residential institution • Fall involving ice-skates, skis, roller-skates or skateboards | school, other institution and public administrative area • Fall involving ice-skates, skis, roller-skates or skateboards | sports and athletics area • Fall involving ice-skates, skis, roller-skates or skateboards | street and highway • Fall involving ice-skates, skis, roller-skates or skateboards | trade and service area • Fall involving ice-skates, skis, roller-skates or skateboards | unspecified place • ICE Protease • ICE-LAP6 Protein • ICE-Like Apoptotic Protease 3 • ICE-Like Apoptotic Protease 6 • Ice Cover • Ice Cream • Ice Hockey • Ice Plant • Ice Sheet • Ice Skating • Ice-Pick Headache • Neapolitan ice cream • Polar Ice Shelf • Sea Ice • Sea Ice Cover • accident to or involving ice-yacht • as cold as ice • black ice • break the ice • break-up of ice • camphor ice • choc-ice • chocolate ice cream • clear sth. of ice • cut no ice • dairy ice cream • de-ice • dead ice • drift ice • dry ice • fall (on)(from) involving ice or snow on stairs and steps • fall involving ice or snow • fall with mention of ice-skates and skis • floating ice • french custard ice cream • french ice cream • hole in the ice • ice age • ice ax • ice axe • ice bag • ice baleen whale • ice bear • ice boulder • ice box • ice cap • ice chest • ice coffee • ice cream • ice cream cone • ice cream soda • ice crystal • ice cube • ice dancing • ice drift • ice field • ice floe • ice fog • ice hockey • ice hockey player • ice hockey rink • ice lolly • ice machine • ice maker • ice mass • ice milk • ice needle • ice over • ice over/up • ice pack • ice pick • ice plant • ice rink • ice shelf • ice show • ice skate • ice skater • ice skating • ice storm • ice tea • ice tongs • ice tray • ice up • ice wagon • ice water • ice yacht • ice-clogged • ice-cold • ice-cream • ice-cream bean • ice-cream cake • ice-cream cone • ice-cream float • ice-cream man • ice-cream parlor • ice-cream parlour • ice-cream pudding • ice-cream seller • ice-cream soda • ice-cream sundae • ice-cream vender • ice-cream vendor • ice-crystal • ice-cube • ice-free • ice-hammer • ice-hockey player • ice-hockey rink • ice-maker • ice-making compartment • ice-pick • ice-skate • ice-skater • ice-skating • ice-skating rink • ice-wagon • pack ice • peach ice cream • shelf ice • snow and ice • soft ice • soft ice cream • strawberry ice cream • vanilla ice cream • water ice
1998 Canada ice storm • A Song of Ice and Fire • Actua Ice Hockey • Alain Côté (ice hockey b. 1957) • Alain Côté (ice hockey b. 1967) • Amery Ice Shelf • Amy's Ice Creams • Asia League Ice Hockey • Australian Ice Hockey League • Bailey Ice Stream • Battle on the Ice • Beaver Glacier (Ross Ice Shelf) • Bertrand Ice Piedmont • Bill Baker (ice hockey) • Billy Harris (ice hockey) • Black Ice (poet) • Blood on Ice • Blue Ice (Airplanes) • Blue ice (Airplanes) • Blue ice (aircraft) • Blue ice (glacial) • Blue ice runway • BlueBell Ice Cream • Bob Berry (ice hockey) • Boris Mikhailov (ice hockey) • Bragg Creek Ice Cave • Brian Burke (ice hockey) • Brian Lee (ice hockey) • Brigham's Ice Cream • Butterfinger (ice cream) • Canyon Creek Ice Cave • Centreman (ice hockey) • Champions on Ice • Clipping (ice hockey) • Cold as Ice (novel) • Colin Patterson (ice hockey) • Colin White (ice hockey) • Columbia ice field • Cook Ice Shelf • Crary Ice Rise • Crunch (ice cream) • Disney on Ice • Don Cherry (ice hockey) • Don Grierson (ice hockey) • Doug Anderson (ice hockey) • Doug Wilson (ice hockey) • Dreyer's Grand Ice Cream Holdings • Dry ice • Ekstrom Ice Shelf • Enforcer (ice hockey) • English Premier Ice Hockey League • Ernest Johnson (ice hockey) • Fimbul Ice Shelf • Fire and Ice (1983 film) • Foundation Ice Stream • Frank Patrick (ice hockey) • Freeze-dried ice cream • Gary Edwards (ice hockey) • George Hay (ice hockey) • George Richardson (ice hockey) • George Sullivan (ice hockey) • Glen Murray (ice hockey) • Gordon Roberts (ice hockey) • Greg Adams (ice hockey b. 1960) • Greg Adams (ice hockey b. 1963) • HB Ice Cream • Harry Oliver (ice hockey) • Harry Watson (ice hockey b. 1898) • Henderson Island (Shackleton Ice Shelf) • Henry Ice Rise • Herbie Lewis (ice hockey) • History of ice hockey in Slovakia • Holiday on Ice • Hotheaded Naked Ice Borer • ICE (disambiguation) • IT'S-IT Ice Cream • Ice (disambiguation) • Ice Accretion Indicator • Ice Age (film) • Ice Age (movie) • Ice Age Trail • Ice Blink • Ice Bowl • Ice Box (arena) • Ice Cream Castle • Ice Cream Cones • Ice Cream Man (film) • Ice Cream Truck • Ice Cream U.S.A. • Ice Cruise of the Baltic Fleet • Ice Cube • Ice Gator • Ice Harbor Lock and Dam • Ice Hockey (1988 video game) • Ice Palace Saint Petersburg • Ice Train • Ice Water Inc. • Ice XII • Ice age • Ice algae • Ice cream cake • Ice cream cakes • Ice cream cones • Ice cream parlor • Ice cream parlors • Ice crystals • Ice dam • Ice dancing • Ice diving • Ice field • Ice fish • Ice hockey • Ice nucleus • Ice on Fire • Ice pack • Ice skate • Ice skating • Ice spike • Ice storm • Ice swimming • Ice tea spoon • Ice wine • Ice-Age • Ice-T • Ice-algae • Ice-breaker game • Ice-skating rink • Inter Ice Age 4 • International Ice Patrol • International ice hockey competitions featuring NHL players • Jack Marshall (ice hockey) • Jack Stewart (ice hockey) • Jack Walker (ice hockey) • Jacques Martin (ice hockey) • James Patrick (ice hockey) • Japan Ice Hockey League • Jelbart Ice Shelf • John Ashley (ice hockey) • John Davidson (ice hockey) • John Erskine (ice hockey) • John Harrington (ice hockey) • Junior ice hockey • Just-Ice • Keith Allen (ice hockey) • Ken Richardson (ice hockey) • Kevin Nugent (ice hockey) • Korff Ice Rise • List of ice cream parlors • London Ice House • Manny Fernandez (ice hockey) • Mauds Ice Cream • McMurdo Ice Shelf • Michael Corbett (ice hockey) • Mike Fisher (ice hockey) • Mike Ramsey (ice hockey) • Miracle on Ice • Moscow University Ice Shelf • Nancy Johnson (ice cream) • National Ice Center • Natural Ice • Neapolitan ice cream • Neil Armstrong (ice hockey) • Neil Smith (ice hockey) • Neutral zone (ice hockey) • Nikkō Ice Bucks • North Greenland Ice Core Project • Northern Patagonian Ice Field • Off side (ice hockey) • Paddy Moran (ice hockey) • Pelicans (ice hockey) • Perry's Ice Cream • Prehistoric Ice Man • Ray Whitney (ice hockey) • Rick Green (ice hockey) • Rick Smith (ice hockey) • Riiser-Larsen Ice Shelf • River of Ice • Roger Wilson (ice hockey) • Ross Ice Shelf • Skating on Thin Ice • Skytrain Ice Rise • Sprite Ice • Sprite Ice (soft drink) • St. Louis Blues (ice hockey) • Stars on Ice • Stephane Richer (ice hockey coach) • Steve Smith (ice hockey) • Steven King (ice hockey) • Studio ICE • The Edge Ice Arena • The Ice Warriors • The Thin Ice • The Wonderful Ice Cream Suit and Other Plays • Tim Thomas (ice hockey) • Tom Hooper (ice hockey) • Turkey men's national ice hockey team • Walking On Thin Ice (song) • Wayne Smith (ice hockey) • Women's Ice Hockey in Great Britain
motor vehicle; automotive vehicle[ClasseHyper.]
Environment, Environmental Impact, Environmental Impacts, Environmental Policies, Environmental Policy, Impact, Environmental, Impacts, Environmental, Policies, Environmental, Policy, Environmental - Hydroxides - Oxides[Hyper.]
Hydrogen Oxide, Water[Hyper.]
Ice (n.) [MeSH]
chose froide (fr)[ClasseParExt.]
chose matérielle inanimée (fr)[Classe...]
ice (n.) [British]
chose froide (fr)[ClasseParExt.]
chose matérielle inanimée naturelle (fr)[Classe...]
(coldness; cold)[termes liés]
building, construction, edifice[Hyper.]
(nervous system; systema nervosum)[termes liés]
garniture; garnishing; trimmings; garnish; topping[ClasseHyper.]
frosting, ice, icing[Dérivé]
object, physical object[Hyper.]
glisten, glister, glitter, scintillation, sparkle - glimmer, glistening, glittering, scintillating, scintillation, sparkle, sparkling, twinkle, twinkling - coruscation, glitter, sparkle - ice, sparkler - aglitter, coruscant, fulgid, glinting, glistering, glittering, glittery, scintillant, scintillating, sparkly[Dérivé]
(coldness; cold)[termes liés]
afters, dessert, pudding, sweet[Hyper.]
chose froide (fr)[ClasseParExt.]
chose matérielle inanimée (fr)[Classe...]
afters, dessert, pudding, sweet[Hyper.]
(coldness; cold)[termes liés]
devenir froid (fr)[Classe]
chill, cool, cool down[Cause]
heat, heat up[Ant.]
nourriture (pour l'homme) (fr)[Classe]
cuisine; art of cooking; cookery; preparation[ClasseHyper.]
frosting, ice, icing[Dérivé]
alter, change, modify[Hyper.]
Ice is water frozen into the solid state. It can appear transparent or opaque bluish-white color, depending on the presence of impurities or air inclusions. The addition of other materials such as soil may further alter the appearance.
Ice appears in nature in forms of snowflakes, hail, icicles, glaciers, pack ice, and entire polar ice caps. It is an important component of the global climate, and plays an important role in the water cycle. Furthermore, ice has numerous cultural applications, from ice cooling of drinks to winter sports and the art of ice sculpting.
The molecules in solid ice may be arranged in different ways, called phases, depending on the temperature and pressure. Usually ice is the phase known as ice Ih, which is the most abundant of the varying solid phases on the Earth's surface. The most common phase transition to ice Ih occurs when liquid water is cooled below 0°C (273.15K, 32°F) at standard atmospheric pressure. It can also deposit from vapour with no intervening liquid phase, such as in the formation of frost.
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, which consists of 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. It is a weak bond, but is critical in controlling the structure of both water and ice.
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, whereas water has a density of 0.9998 g/cm³ at the same temperature. 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 (93 K).
The effect of expansion during freezing can be dramatic, and is a basic cause of freeze-thaw weathering of rock in nature. 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, then leak water after thawing.
The result of this process is that ice (in its most common form) floats on liquid water, which is an important feature in Earth's biosphere. It has been argued that without this property natural bodies of water would freeze, in some cases permanently, from the bottom up, resulting in a loss of bottom-dependent animal and plant life in fresh and sea 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 a sheltered environment for 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, which in turn provide food for animals such as krill and specialised fish like 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. During the melting process, the temperature remains constant at 0 °C. While melting, any energy added breaks the hydrogen bonds between ice (water) molecules. Energy becomes available to increase 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 is shifted toward slightly lower energies. Thus, ice appears blue, with a slightly greener tint than for 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 the ice itself. For instance, icebergs containing impurities (e.g., sediments, algae, air bubbles) can appear brown, grey or green.
It has long been believed that ice is slippery because the pressure of an object in contact with it causes a thin layer to melt. For example, the blade of an ice skate, exerting pressure on the ice, melts a thin layer, providing lubrication between the ice and the blade. This explanation, called "pressure melting", originated in 19th century. This however did not account for skating on ice temperatures lower than -3.5 °C, whereas skaters often skate on lower temperature ice. In 20th century an alternative explanation, called "friction heating" was proposed, whereby friction of the material was causing the ice layer melting. However, this theory also failed to explain skating at low temperature. In fact, neither explanation explained why ice is slippery when standing still even at below-zero temperatures.
This explanation has come into doubt with the proposal that ice molecules in contact with air 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 semiliquid state, providing lubrication regardless of pressure against the ice exerted by any object.
Ice that is found at sea may be in the form of sea ice, pack ice, or icebergs. 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 is often an important source of seasonal fresh water.
Rime is a type of ice formed on cold objects when drops of water crystallize on them. This can be observed in foggy weather, when the temperature drops during the night. Soft rime contains a high proportion of trapped air, making it appear white rather than transparent, and giving it a density about one quarter of that of pure ice. Hard rime is comparatively denser.
Aufeis is 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 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.
Clathrate hydrates are forms of ice that contain gas molecules trapped within its crystal lattice.
Pancake ice is a formation of ice generally created in areas with less calm conditions.
Ice discs are circular formations of ice surrounded by water in a river.
Ice pellets are a form of precipitation consisting of small, translucent balls of ice. This form of precipitation is also known as sleet. Ice pellets are usually (but not always) smaller than hailstones. They often bounce when they hit the ground, and generally do not freeze into a solid mass unless mixed with freezing rain. The METAR code for ice pellets is PL.
Ice pellets form when a layer of above-freezing air is located between 1,500 metres (4,900 ft) and 3,000 metres (9,800 ft) above the ground, with sub-freezing air both above and below it. This causes the partial or complete melting of any snowflakes falling through the warm layer. As they fall back into the sub-freezing layer closer to the surface, they re-freeze into ice pellets. However, if the sub-freezing layer beneath the warm layer is too small, the precipitation will not have time to re-freeze, and freezing rain will be the result at the surface. A temperature profile showing a warm layer above the ground is most likely to be found in advance of a warm front during the cold season, but can occasionally be found behind a passing cold front.
Like other precipitation, 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 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). GR is derived from the French word grêle. Smaller-sized hail, as well as snow pellets, use the coding of GS, which is short for the French word grésil. Stones just larger than golf ball-sized are one of the most frequently reported hail sizes. Hailstones can grow to 15 centimetres (6 in) and weigh more than .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 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 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 the frequency of hail by promoting evaporational 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.
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, 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) 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 include particles of silver iodide and dry ice, and these are used to stimulate precipitation in cloud seeding.
Once a droplet has frozen, it grows in the water-supersaturated air, when the temperature remains below the freezing point. The droplet then grows by condensation of water vapor onto the ice surfaces. Air saturation with water is maintained by continuous simultaneous evaporation of water droplets. Thus ice crystals grow at the expense of water droplets in a process called the Wegner-Bergeron-Findeison process. These large crystals are an efficient source of precipitation, since they fall through the atmosphere due to their weight, and may collide and aggregate in clusters. These aggregates are snowflakes, and are usually the type of ice particle that falls to the ground. Guinness World Records list the world’s largest snowflakes as those of January 1887 at Fort Keogh, Montana; allegedly one measured 38 cm (15 inches) wide.
The exact details of the sticking mechanism remain controversial. Possibilities include mechanical interlocking, sintering, electrostatic attraction as well as the existence of a "sticky" liquid-like layer on the crystal surface. The individual ice crystals often have hexagonal symmetry. Although the ice is clear, scattering of light by the crystal facets and hollows/imperfections mean that the crystals often appear white in color due to diffuse reflection of the whole spectrum of light by the small ice particles. The shape of the snowflake is determined broadly by the temperature and humidity at which it is formed. Rarely, at a temperature of around −2 °C (28 °F), snowflakes can form in threefold symmetry — triangular snowflakes. The most common snow particles are visibly irregular, although near-perfect snowflakes may be more common in pictures because they are more visually appealing. It is unlikely that any two snowflakes are alike due to the estimated 1019 (10 quintillion) water molecules which make up a typical snowflake, which grow at different rates and in different patterns depending on the changing temperature and humidity within the atmosphere that the snowflake falls through on its way to the ground. The METAR code for snow is SN, while snow showers are coded SHSN.
Diamond dust, also known as ice needles or ice crystals, forms at temperatures approaching −40 °F (−40 °C) due to air with slightly higher moisture from aloft mixing with colder, surface based air. The METAR identifier for diamond dust within international hourly weather reports is IC.
Ice is now mechanically produced on a large scale, but before refrigeration was developed ice was harvested from natural sources for human use.
Ice has long been valued as a means of cooling. In 400 BC Iran, Persian engineers had already mastered the technique of storing ice in the middle of summer in the desert. The ice was brought in during the winters from nearby mountains in bulk amounts, and stored in specially designed, naturally cooled refrigerators, called yakhchal (meaning ice storage). This was a large underground space (up to 5000 m³) that had thick walls (at least two meters at the base) made out of a special mortar called sārooj, composed of sand, clay, egg whites, lime, goat hair, and ash in specific proportions, and which was known to be resistant to heat transfer. This mixture was thought to be completely water impenetrable. The space often had access to a Qanat, and often contained a system of windcatchers which could easily bring temperatures inside the space down to frigid levels on summer days. The ice was used to chill treats for royalty.
There were thriving industries in the 16/17th century in UK whereby low lying areas along the River 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 was copied from the Chinese who had been doing it for thousands of years. This was reportedly 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 big business. Frederic Tudor, who became known as the “Ice King,” worked on developing better insulation products for the long distance shipment of ice, especially to the tropics; this became known as the ice trade.
Until recently,[when?] the Hungarian Parliament building used ice harvested in the winter from Lake Balaton for air conditioning. Icehouses were used to store ice formed in the winter, to make ice available all year long, and early refrigerators were known as iceboxes, because they had a block of ice in them. In many cities, it was not unusual to have a regular ice delivery service during the summer. The advent of artificial refrigeration technology has since made delivery of ice obsolete.
Ice harvesting is still done for ice and snow sculpture events. A swing saw is used to get ice out of the river for the Harbin International Ice and Snow Sculpture Festival each year. A swing saws is used to cut ice out from the frozen surface of the Songhua River. Many ice sculptures are made from the ice.
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 ice makers 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.
For small-scale ice production, many modern home refrigerators can also make ice with a built in icemaker, which will typically make ice cubes or crushed ice. Stand-alone icemaker units that make ice cubes are often called ice machines.
Ice also plays a central role in winter recreation and in many sports such as ice skating, tour skating, ice hockey, ice fishing, ice climbing, curling, broomball and sled racing on bobsled, luge and skeleton. Many of the different sports played on ice get international attention every four years during the Winter Olympic Games.
A sort of sailboat on blades gives rise to ice yachting. The human quest for excitement has even led to ice racing, where drivers must speed on lake ice, while also controlling the skid of their vehicle (similar in some ways to dirt track racing). The sport has even been modified for ice rinks.
Ice can also be an obstacle; for harbors near the poles, being ice-free is an important advantage; ideally, all year long. Examples are Murmansk (Russia), Petsamo (Russia, formerly Finland) and Vardø (Norway). Harbors which are not ice-free are opened up using icebreakers.
Ice forming on roads is a dangerous winter hazard. Black ice is very difficult to see, because it lacks the expected frosty surface. Whenever there is freezing rain or snow which occurs at a temperature near the melting point, it is common for ice to build up on the windows of vehicles. Driving safely requires the removal of the ice build-up. Ice scrapers are tools designed to break the ice free and clear the windows, though removing the ice can be a long and laborious process.
Far enough below the freezing point, a thin layer of ice crystals can form on the inside surface of windows. This usually happens when a vehicle has been left alone after being driven for a while, but can happen while driving, if the outside temperature is low enough. Moisture from the driver's breath is the source of water for the crystals. It is troublesome to remove this form of ice, so people often open their windows slightly when the vehicle is parked in order to let the moisture dissipate, and it is now common for cars to have rear-window defrosters to solve the problem. A similar problem can happen in homes, which is one reason why many colder regions require double-pane windows for insulation.
When the outdoor temperature stays below freezing for extended periods, very thick layers of ice can form on lakes and other bodies of water, although places with flowing water require much colder temperatures. The ice can become thick enough to drive onto with automobiles and trucks. Doing this safely requires a thickness of at least 30 cm (one foot).
For ships, ice presents two distinct hazards. Spray and freezing rain can produce an ice build-up on the superstructure of a vessel sufficient to make it unstable, and to require it to be hacked off or melted with steam hoses. And icebergs — large masses of ice floating in water (typically created when glaciers reach the sea) — can be dangerous if struck by a ship when underway. Icebergs have been responsible for the sinking of many ships, the most famous probably being the Titanic.
For aircraft, ice can cause a number of dangers. As an aircraft climbs, it passes through air layers of different temperature and humidity, some of which may be conducive to ice formation. If ice forms on the wings or control surfaces, this may adversely affect the flying qualities of the aircraft. During the first non-stop flight of the Atlantic, the British aviators Captain John Alcock and Lieutenant Arthur Whitten Brown encountered such icing conditions – Brown left the cockpit and climbed onto the wing several times to remove ice which was covering the engine air intakes of the Vickers Vimy aircraft they were flying.
A particular icing vulnerability associated with reciprocating internal combustion engines is the carburetor. As air is sucked through the carburetor into the engine, the local air pressure is lowered, which causes adiabatic cooling. So, in humid near-freezing conditions, the carburetor will be colder, and tend to ice up. This will block the supply of air to the engine, and cause it to fail. For this reason, aircraft reciprocating engines with carburetors are provided with carburetor air intake heaters. The increasing use of fuel injection—which does not require carburetors—has made "carb icing" less of an issue for reciprocating engines.
Jet engines do not experience carb icing, but recent evidence indicates that they can be slowed, stopped, or damaged by internal icing in certain types of atmospheric conditions much more easily than previously believed. In most cases, the engines can be quickly restarted and flights are not endangered, but research continues to determine the exact conditions which produce this type of icing, and find the best methods to prevent, or reverse it, in flight.
Most liquids freeze at higher temperatures under increased pressure; because the pressure helps to hold the molecules together. However, the strong hydrogen bonds in water make it different: water freezes at a temperature below 0 °C under a pressure higher than 1 atm (0.10 MPa). Consequently, water also remains frozen at a temperature above 0 °C under a pressure lower than 1 atm. The melting of ice under high pressures is thought to contribute to the movement of glaciers.
Ice, water, and water vapour can coexist at the triple point, which is exactly 0.01 °C or 273.16 K (by definition) at a pressure of 611.73 Pa. 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 fifteen separate known phases. With care all these phases except ice X can be recovered at ambient pressure and low temperature. The types are differentiated by their crystalline structure, ordering and density. There are also two metastable phases of ice under pressure, both fully hydrogen-disordered; these are IV and XII. Ice XII was discovered in 1996. In 2006, XIII and XIV were discovered. Ices XI, XIII, and XIV are hydrogen-ordered forms of ices Ih, V, and XII respectively. In 2009, ice XV 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), low-density amorphous ice (LDA), high-density amorphous ice (HDA), very high-density amorphous ice (VHDA) and hyperquenched glassy water (HGW).
In outer space, hexagonal crystalline ice (the predominant form found on Earth) is extremely rare. Amorphous ice is more common; however, hexagonal crystalline ice can be formed via volcanic action.
|Amorphous ice||Amorphous ice is an ice lacking crystal structure. Amorphous ice exists in three forms: low-density (LDA) formed at atmospheric pressure, or below, high density (HDA) and very high density amorphous ice (VHDA), forming at higher pressures. LDA forms by extremely quick cooling of liquid water ("hyperquenched glassy water", HGW), by depositing water vapour on very cold substrates ("amorphous solid water", ASW) or by heating high density forms of ice at ambient pressure ("LDA").|
|Ice Ih||Normal hexagonal crystalline ice. Virtually all ice in the biosphere is ice Ih, with the exception only of a small amount of ice Ic.|
|Ice Ic||A metastable cubic crystalline variant of ice. The oxygen atoms are arranged in a diamond structure. It is produced at temperatures between 130 and 220 K, and can exist up to 240 K, when it transforms into ice Ih. It may occasionally be present in the upper atmosphere.|
|Ice II||A rhombohedral crystalline form with highly ordered structure. Formed from ice Ih by compressing it at temperature of 190–210 K. When heated, it undergoes transformation to ice III.|
|Ice III||A tetragonal crystalline ice, formed by cooling water down to 250 K at 300 MPa. Least dense of the high-pressure phases. Denser than water.|
|Ice IV||A metastable rhombohedral phase. It can be formed by heating high-density amorphous ice slowly at a pressure of 810 MPa. It doesn't form easily without a nucleating agent.|
|Ice V||A monoclinic crystalline phase. Formed by cooling water to 253 K at 500 MPa. Most complicated structure of all the phases.|
|Ice VI||A tetragonal crystalline phase. Formed by cooling water to 270 K at 1.1 GPa. Exhibits Debye relaxation.|
|Ice VII||A cubic phase. The hydrogen atoms' positions are disordered. Exhibits Debye relaxation. The hydrogen bonds form two interpenetrating lattices.|
|Ice VIII||A more ordered version of ice VII, where the hydrogen atoms assume fixed positions. Formed from ice VII, by cooling it below 5 °C (278 K).|
|Ice IX||A tetragonal phase. Formed gradually from ice III by cooling it from 208 K to 165 K, stable below 140 K and pressures between 200 MPa and 400 MPa. It has density of 1.16 g/cm3, slightly higher than ordinary ice.|
|Ice X||Proton-ordered symmetric ice. Forms at about 70 GPa.|
|Ice XI||An orthorhombic, low-temperature equilibrium form of hexagonal ice. It is ferroelectric. Ice XI is considered the most stable configuration of ice Ih. The natural transformation process is very slow and ice XI has been found in Antarctic ice 100 to 10,000 years old. That study indicated that the temperature below which ice XI forms is −36 °C (240 K).|
|Ice XII||A tetragonal, metastable, dense crystalline phase. It is observed in the phase space of ice V and ice VI. It can be prepared by heating high-density amorphous ice from 77 K to about 183 K at 810 MPa. It has a density of 1.3 g cm−3 at 127 K (i.e., approximately 1.3 times more dense than water).|
|Ice XIII||A monoclinic crystalline phase. Formed by cooling water to below 130 K at 500 MPa. The proton-ordered form of ice V.|
|Ice XIV||An orthorhombic crystalline phase. Formed below 118 K at 1.2 GPa. The proton-ordered form of ice XII.|
|Ice XV||The proton-ordered form of ice VI formed by cooling water to around 80–108 K at 1.1 GPa.|
The solid phases of several other volatile substances are also referred to as ices; generally a volatile is classed as an ice if its melting point lies above ~100 K. The best known example is dry ice, the solid form of carbon dioxide.
A "magnetic analogue" of ice is also realized in some insulating magnetic materials in which the magnetic moments mimic the position of protons in water ice and obey energetic constraints similar to the Bernal-Fowler ice rules arising from the geometrical frustration of the proton configuration in water ice. These materials are called spin ice.
|Look up ice in Wiktionary, the free dictionary.|
|Wikimedia Commons has media related to: Ice|