Ice is water frozen into a solid state. 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.
In the Solar System, ice is abundant and occurs naturally from as close to the Sun as Mercury to as far away as the Oort cloud objects. Beyond the Solar System, it occurs as interstellar ice. It is abundant on Earth's surface – particularly in the polar regions and above the snow line – and, as a common form of precipitation and deposition, plays a key role in Earth's water cycle and climate. It falls as snowflakes and hail or occurs as frost, icicles or ice spikes.
Ice molecules can exhibit eighteen or more different phases (packing geometries) that depend on temperature and pressure. When water is cooled rapidly (quenching), up to three different types of amorphous ice can form depending on the history of its pressure and temperature. When cooled slowly correlated proton tunneling occurs below −253.15 °C (20 K, −423.67 °F) giving rise to macroscopic quantum phenomena. Virtually all the ice on Earth's surface and in its atmosphere is of a hexagonal crystalline structure denoted as ice Ih (spoken as "ice one h") with minute traces of cubic ice denoted as ice Ic. The most common phase transition to ice Ih occurs when liquid water is cooled below 0 °C (273.15 K, 32 °F) at standard atmospheric pressure. It may also be deposited directly by water vapor, as happens in the formation of frost. The transition from ice to water is melting and from ice directly to water vapor is sublimation.
Ice sample cored in Antarctica, containing air bubbles that are thousands of years old
|Density (ρ)||0.9167–0.9168 g/cm3|
|Refractive index (n)||1.309|
|Young's modulus (E)||3400 to 37,500 kg-force/cm3|
|Tensile strength (σt)||5 to 18 kg-force/cm2|
|Compressive strength (σc)||24 to 60 kg-force/cm2|
|Poisson's ratio (ν)||0.36±0.13|
|Thermal conductivity (k)||0.0053(1 + 0.105 θ) cal/(cm s K), θ = temperature in °C|
|Linear thermal expansion coefficient (α)||5.5×10−5|
|Specific heat capacity (c)||0.5057 − 0.001863 θ cal/(g K), θ = absolute value of temperature in °C|
|Dielectric constant (εr)||~3.15|
|The properties of ice vary substantially with temperature, purity and other factors.|
As a naturally occurring crystalline inorganic solid with an ordered structure, ice is considered to be 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; while it is a weak bond, it is nonetheless 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 (which is equivalent to volumetric expansion of 9%). The density of ice is 0.9167–0.9168 g/cm3 at 0 °C and standard atmospheric pressure (101,325 Pa), whereas water has a density of 0.9998–0.999863 g/cm3 at the same temperature and pressure. 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).
When water freezes, it increases in volume (about 9% for fresh water). The effect of expansion during freezing can be dramatic, and ice expansion 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.
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 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.
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, as shown in the phase diagram below. 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 273.16 K (0.01 °C) at a pressure of 611.657 Pa. The kelvin was in fact defined as 1/ 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 18 separate known crystalline phases. With care, at least 15 of these phases (one of 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 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 ice (ASW) of varying densities. 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) is formed by compression of ordinary ice Ih or LDA at GPa pressures. Very-high-density ASW (VHDA) is HDA slightly warmed to 160K under 1–2 GPa pressures.
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 by volcanic action.
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) the structure may shift to a more stable face-centered cubic lattice.
|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 does not 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. It is 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.|
|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.|
|Ice XVI||The least dense crystalline form of water, topologically equivalent to the empty structure of sII clathrate hydrates.|
|Square ice||Square ice crystals form at room temperature when squeezed between two layers of graphene. The material was a new crystalline phase of ice, joining 17 others, when it was first reported in 2014. The research derived from the earlier discovery that water vapor and liquid water could pass through laminated sheets of graphene oxide, unlike smaller molecules such as helium. The effect is thought to be driven by the van der Waals force, which may involve more than 10,000 atmospheres of pressure.|
The low coefficient of friction ("slipperiness") of ice has been attributed to the pressure of an object coming into contact with the ice, melting a thin layer of the ice and allowing the object to glide across the surface. For example, the blade of an ice skate, upon exerting pressure on the ice, would melt a thin layer, providing lubrication between the ice and the blade. This explanation, called "pressure melting", originated in the 19th century. It, however, did not account for skating on ice temperatures lower than −4 °C (25 °F; 269 K), which is often skated upon.
A second theory describing the coefficient of friction of ice 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 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.
A third theory is "friction heating", which suggests that friction of the material is the cause of the ice layer melting. However, this theory does not sufficiently explain why ice is slippery when standing still even at below-zero temperatures.
A comprehensive theory of ice friction takes into account all the above-mentioned friction mechanisms. This model allows quantitative estimation of the friction coefficient of ice against various materials as a function of temperature and sliding speed. In typical conditions related to winter sports and tires of a vehicle on ice, melting of a thin ice layer due to the frictional heating is the primary reason for the slipperiness.
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 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 the sea bottom. Ice which calves (breaks off) from an ice shelf or glacier may become an iceberg. Sea ice can be forced together by currents and winds to form pressure ridges up to 12 metres (39 ft) tall. Navigation through areas of sea ice occurs in openings called "polynyas" or "leads" or requires the use of a special ship called an "icebreaker".
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.
Freezing rain is a type of winter storm called an ice storm where rain falls and then freezes producing a glaze of ice. Ice can also form icicles, similar to stalactites in appearance, or stalagmite-like forms as water drips and re-freezes.
The term "ice dam" has three meanings (others discussed below). On structures, an ice dam is the buildup of ice on a sloped roof which stops melt water from draining properly and can cause damage from water leaks in buildings.
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 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 to keep navigation possible.
Pancake ice is a formation of ice generally created in areas with less calm conditions.
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 the ice which often settles when loaded with snow.
Shelf ice occurs when floating pieces of ice are driven by the wind piling up on the windward shore.
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 dense.
Ice pellets are a form of precipitation consisting of small, translucent balls of ice. 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 are usually 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 and 3,000 metres (4,900 and 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) and GS for smaller. 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 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 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 are used in cloud seeding. The droplet then grows by condensation of water vapor onto the ice surfaces.
So-called "diamond dust", 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. The METAR identifier for diamond dust within international hourly weather reports is IC.
In fresh ambient melting describes a phase transition from solid to liquid.
To melt ice means breaking the 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 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 velocity 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 a velocity 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)α, with α = 5/ for T∞ much greater than 8 °C, and α = 4/ for in between temperatures T∞.
In salty ambient conditions, dissolution rather than melting often causes 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. Hence dissolution is rate limited by salt transport whereas melting can occur at much higher rates that are characteristic for heat transport.
Humans have used ice for cooling and food preservation for centuries, relying on harvesting natural ice in various forms and then transitioning to the mechanical production of the material. Ice also presents a challenge to transportation in various forms and a setting for winter sports.
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 of a special mortar called sarooj, 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 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 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 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.
Trieste sent ice to Egypt, Corfu, and Zante; Switzerland sent it to France; and Germany sometimes was supplied from Bavarian lakes. 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 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 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.
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 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. Stand-alone icemaker units that make ice cubes are often called ice machines.
Ice can present challenges to safe transportation on land, sea and in the air.
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 being the Titanic. 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.
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 across 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.
One vulnerability effected by icing that is 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. Thus, 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.
Ice also plays a central role in winter recreation and in many sports such as ice skating, tour skating, ice hockey, bandy, 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. Another sport is 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.
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 or around 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.
A Song of Ice and Fire is a series of epic fantasy novels by the American novelist and screenwriter George R. R. Martin. He began the first volume of the series, A Game of Thrones, in 1991, and it was published in 1996. Martin, who initially envisioned the series as a trilogy, has published five out of a planned seven volumes. The fifth and most recent volume of the series published in 2011, A Dance with Dragons, took Martin six years to write. He is currently writing the sixth novel, The Winds of Winter.
A Song of Ice and Fire takes place on the fictional continents Westeros and Essos. The point of view of each chapter in the story is a limited perspective of a range of characters growing from nine in the first novel, to 31 characters by the fifth novel. Three main stories interweave: a dynastic war among several families for control of Westeros, the rising threat of the supernatural Others in the northernmost reaches of Westeros, and the ambition of Daenerys Targaryen, the deposed king's exiled daughter, to assume the Iron Throne.
Martin's inspirations included the Wars of the Roses and the French historical novels The Accursed Kings by Maurice Druon. A Song of Ice and Fire received praise for its diverse portrayal of women and religion, as well as its realism. An assortment of disparate and subjective points of view confronts the reader, and the success or survival of point of view characters is never assured. Within the often morally ambiguous world of A Song of Ice and Fire, questions concerning loyalty, pride, human sexuality, piety, and the morality of violence frequently arise.
The books have sold 90 million copies worldwide as of April 2019, after having been translated into 47 languages as of January 2017. The fourth and fifth volumes reached the top of The New York Times Best Seller lists upon their releases. Among the many derived works are several prequel novellas, a TV series, a comic book adaptation, and several card, board, and video games.Antarctica
Antarctica (UK: or , US: (listen)) is Earth's southernmost continent. It contains the geographic South Pole and is situated in the Antarctic region of the Southern Hemisphere, almost entirely south of the Antarctic Circle, and is surrounded by the Southern Ocean. At 14,200,000 square kilometres (5,500,000 square miles), it is the fifth-largest continent. For comparison, Antarctica is nearly twice the size of Australia. At 0.00008 people per square kilometre, it is by far the least densely populated continent. About 98% of Antarctica is covered by ice that averages 1.9 km (1.2 mi; 6,200 ft) in thickness, which extends to all but the northernmost reaches of the Antarctic Peninsula.
Antarctica, on average, is the coldest, driest, and windiest continent, and has the highest average elevation of all the continents. Most of Antarctica is a polar desert, with annual precipitation of only 200 mm (8 in) along the coast and far less inland. The temperature in Antarctica has reached −89.2 °C (−128.6 °F) (or even −94.7 °C (−135.8 °F) as measured from space), though the average for the third quarter (the coldest part of the year) is −63 °C (−81 °F). Anywhere from 1,000 to 5,000 people reside throughout the year at research stations scattered across the continent. Organisms native to Antarctica include many types of algae, bacteria, fungi, plants, protista, and certain animals, such as mites, nematodes, penguins, seals and tardigrades. Vegetation, where it occurs, is tundra.
Antarctica is noted as the last region on Earth in recorded history to be discovered, unseen until 1820 when the Russian expedition of Fabian Gottlieb von Bellingshausen and Mikhail Lazarev on Vostok and Mirny sighted the Fimbul ice shelf. The continent, however, remained largely neglected for the rest of the 19th century because of its hostile environment, lack of easily accessible resources, and isolation. In 1895, the first confirmed landing was conducted by a team of Norwegians.
Antarctica is a de facto condominium, governed by parties to the Antarctic Treaty System that have consulting status. Twelve countries signed the Antarctic Treaty in 1959, and thirty-eight have signed it since then. The treaty prohibits military activities and mineral mining, prohibits nuclear explosions and nuclear waste disposal, supports scientific research, and protects the continent's ecozone. Ongoing experiments are conducted by more than 4,000 scientists from many nations.Climate change
Climate change occurs when changes in Earth's climate system result in new weather patterns that last for at least a few decades, and maybe for millions of years. The climate system comprises five interacting parts, the atmosphere (air), hydrosphere (water), cryosphere (ice and permafrost), biosphere (living things), and lithosphere (earth's crust and upper mantle). The climate system receives nearly all of its energy from the sun, with a relatively tiny amount from earth's interior. The climate system also gives off energy to outer space. The balance of incoming and outgoing energy, and the passage of the energy through the climate system, determines Earth's energy budget. When the incoming energy is greater than the outgoing energy, earth's energy budget is positive and the climate system is warming. If more energy goes out, the energy budget is negative and earth experiences cooling.
As this energy moves through Earth's climate system, it creates Earth's weather and long-term averages of weather are called "climate". Changes in the long term average are called "climate change". Such changes can be the result of "internal variability", when natural processes inherent to the various parts of the climate system alter Earth's energy budget. Examples include cyclical ocean patterns such as the well-known El Niño–Southern Oscillation and less familiar Pacific decadal oscillation and Atlantic multidecadal oscillation. Climate change can also result from "external forcing", when events outside of the climate system's five parts nonetheless produce changes within the system. Examples include changes in solar output and volcanism.
Human activities can also change earth's climate, and are presently driving climate change through global warming. There is no general agreement in scientific, media or policy documents as to the precise term to be used to refer to anthropogenic forced change; either "global warming" or "climate change" may be used. The first describes the average effect on a global scale, whilst the second describes how different geographical regions are affected differently.
The field of climatology incorporates many disparate fields of research. For ancient periods of climate change, researchers rely on evidence preserved in climate proxies, such as ice cores, ancient tree rings, geologic records of changes in sea level, and glacial geology. Physical evidence of current climate change covers many independent lines of evidence, a few of which are temperature records, the disappearance of ice, and extreme weather events.Glacier
A glacier (US: or UK: ) is a persistent body of dense ice that is constantly moving under its own weight; it forms where the accumulation of snow exceeds its ablation (melting and sublimation) over many years, often centuries. Glaciers slowly deform and flow due to stresses induced by their weight, creating crevasses, seracs, and other distinguishing features. They also abrade rock and debris from their substrate to create landforms such as cirques and moraines. Glaciers form only on land and are distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water.
On Earth, 99% of glacial ice is contained within vast ice sheets (also known as "continental glaciers") in the polar regions, but glaciers may be found in mountain ranges on every continent including Oceania's high-latitude oceanic island countries such as New Zealand and Papua New Guinea. Between 35°N and 35°S, glaciers occur only in the Himalayas, Andes, Rocky Mountains, a few high mountains in East Africa, Mexico, New Guinea and on Zard Kuh in Iran. Glaciers cover about 10 percent of Earth's land surface. Continental glaciers cover nearly 13 million km2 (5 million sq mi) or about 98 percent of Antarctica's 13.2 million km2 (5.1 million sq mi), with an average thickness of 2,100 m (7,000 ft). Greenland and Patagonia also have huge expanses of continental glaciers.Glacial ice is the largest reservoir of fresh water on Earth. Many glaciers from temperate, alpine and seasonal polar climates store water as ice during the colder seasons and release it later in the form of meltwater as warmer summer temperatures cause the glacier to melt, creating a water source that is especially important for plants, animals and human uses when other sources may be scant. Within high-altitude and Antarctic environments, the seasonal temperature difference is often not sufficient to release meltwater.
Since glacial mass is affected by long-term climatic changes, e.g., precipitation, mean temperature, and cloud cover, glacial mass changes are considered among the most sensitive indicators of climate change and are a major source of variations in sea level.
A large piece of compressed ice, or a glacier, appears blue, as large quantities of water appear blue. This is because water molecules absorb other colors more efficiently than blue. The other reason for the blue color of glaciers is the lack of air bubbles. Air bubbles, which give a white color to ice, are squeezed out by pressure increasing the density of the created ice.Hockey
Hockey is a sport in which two teams play against each other by trying to manoeuvre a ball or a puck into the opponent's goal using a hockey stick. There are many types of hockey such as bandy, field hockey, and ice hockey.
In most of the world, hockey refers to field hockey, while in Canada, the United States, Finland, Sweden, Latvia, the Czech Republic and Slovakia, hockey usually refers to ice hockey.Ice-T
Tracy Lauren Marrow (born February 16, 1958), better known by his stage name Ice-T, is an American musician, rapper, songwriter, actor, record producer, and author. He began his career as an underground rapper in the 1980s and was signed to Sire Records in 1987, when he released his debut album Rhyme Pays; the second hip-hop album to carry an explicit content sticker after Slick Rick's La Di Da Di. The following year, he founded the record label Rhyme $yndicate Records (named after his collective of fellow hip-hop artists called the "Rhyme $yndicate") and released another album, Power, which went on to go Platinum. He also released several other albums that went Gold.
He co-founded the heavy metal band Body Count, which he introduced on his 1991 rap album O.G.: Original Gangster, on the track titled "Body Count". The band released their self-titled debut album in 1992. Ice-T encountered controversy over his track "Cop Killer", which glamorized killing police officers. Ice-T asked to be released from his contract with Warner Bros. Records, and his next solo album, Home Invasion, was released later in February 1993 through Priority Records. Body Count's next album was released in 1994, and Ice-T released two more albums in the late-1990s. Since 2000, he has portrayed NYPD Detective/Sergeant Odafin Tutuola on the NBC police drama Law & Order: Special Victims Unit.Ice Cube
O'Shea Jackson (born June 15, 1969), known professionally as Ice Cube, is an American rapper, actor, producer, director and writer.
Ice Cube initially gained recognition as a member of the hip hop group C.I.A. in 1984, which gained limited commercial success prior to disbanding three years later. Ice Cube, alongside Dr. Dre and Eazy E, then formed the group N.W.A, where he gained extreme notoriety as the group's primary songwriter and performer, noted for becoming one of the founding artists of gangsta rap, and pushing the boundaries of lyrical content in mainstream popular music, as well as visual imagery in music videos.After leaving N.W.A in December 1989, Ice Cube embarked on a successful solo career, releasing the albums AmeriKKKa's Most Wanted (1990) and Death Certificate (1991), both of which have attained platinum certification in the United States, while also being classed as defining albums of the 1990s. Much of his musical output has contained harsh socio-political commentary and storytelling, which has earned him several accolades from multiple publications and artists, often cited as an influence and one of the best rappers of all time.Following the release of Death Certificate, Ice Cube transitioned into film, where his popularity was further enhanced by his starring role in Boyz n the Hood (1991), where his performance was heavily praised. He also wrote and starred in the Friday film series, which contributed to reinventing his public image as a movie star. Ice Cube has also featured in the Barbershop, Ride Along, and XXX film series, while also serving as a producer to several other films, including Straight Outta Compton (2015), a biographical film depicting the career of N.W.A..
As a businessman, Ice Cube has founded his clothing line, Solo by Cube, as well as the 3 on 3 basketball league Big3, which predominately features retired NBA players.Ice age
An ice age is a long period of reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth is currently in the Quaternary glaciation, known in popular terminology as the Ice Age. Individual pulses of cold climate are termed "glacial periods" (or, alternatively, "glacials", "glaciations", "glacial stages", "stadials", "stades", or colloquially, "ice ages"), and intermittent warm periods are called "interglacials" or "interstadials" with both climatic pulses part of the Quaternary or other periods in Earth's history.In the terminology of glaciology, ice age implies the presence of extensive ice sheets in both northern and southern hemispheres. By this definition, we are in an interglacial period—the Holocene. The amount of heat trapping gases emitted into Earth's Oceans and atmosphere will prevent the next ice age, which otherwise would begin in around 50,000 years, and likely more glacial cycles.Ice cream
Ice cream (derived from earlier iced cream or cream ice) is a sweetened frozen food typically eaten as a snack or dessert. It may be made from dairy milk or cream, or soy, cashew, coconut or almond milk, and is flavored with a sweetener, either sugar or an alternative, and any spice, such as cocoa or vanilla. Colourings are usually added, in addition to stabilizers. The mixture is stirred to incorporate air spaces and cooled below the freezing point of water to prevent detectable ice crystals from forming. The result is a smooth, semi-solid foam that is solid at very low temperatures (below 2 °C or 35 °F). It becomes more malleable as its temperature increases.
The meaning of the name "ice cream" varies from one country to another. Terms such as "frozen custard," "frozen yogurt," "sorbet," "gelato," and others are used to distinguish different varieties and styles. In some countries, such as the United States, "ice cream" applies only to a specific variety, and most governments regulate the commercial use of the various terms according to the relative quantities of the main ingredients, notably the amount of cream. Products that do not meet the criteria to be called ice cream are sometimes labelled "frozen dessert" instead. In other countries, such as Italy and Argentina, one word is used for all variants. Analogues made from dairy alternatives, such as goat's or sheep's milk, or milk substitutes (e.g., soy milk or tofu), are available for those who are lactose intolerant, allergic to dairy protein, or vegan.
Ice cream may be served in dishes, for eating with a spoon, or licked from edible cones. Ice cream may be served with other desserts, such as apple pie, or as an ingredient in ice cream floats, sundaes, milkshakes, ice cream cakes and even baked items, such as Baked Alaska.Ice hockey
Ice hockey is a contact team sport played on ice, usually in a rink, in which two teams of skaters use their sticks to shoot a vulcanized rubber puck into their opponent's net to score points. The sport is known to be fast-paced and physical, with teams usually consisting of six players each: one goaltender, and five players who skate up and down the ice trying to take the puck and score a goal against the opposing team.
Ice hockey is most popular in Canada, central and eastern Europe, the Nordic countries, Russia and the United States. Ice hockey is the official national winter sport of Canada. In addition, ice hockey is the most popular winter sport in Belarus, Croatia, the Czech Republic, Finland, Latvia, Russia, Slovakia, Sweden, and Switzerland. North America's National Hockey League (NHL) is the highest level for men's ice hockey and the strongest professional ice hockey league in the world. The Kontinental Hockey League (KHL) is the highest league in Russia and much of Eastern Europe. The International Ice Hockey Federation (IIHF) is the formal governing body for international ice hockey, with the IIHF managing international tournaments and maintaining the IIHF World Ranking. Worldwide, there are ice hockey federations in 76 countries.In Canada, the United States, Nordic countries, and some other European countries the sport is known simply as hockey; the name "ice hockey" is used in places where "hockey" more often refers to the more popular field hockey, such as countries in South America, Asia, Africa, Australasia, and some European countries including the United Kingdom, Ireland and the Netherlands.Ice hockey is believed to have evolved from simple stick and ball games played in the 18th and 19th centuries in the United Kingdom and elsewhere. These games were brought to North America and several similar winter games using informal rules were developed, such as shinny and ice polo. The contemporary sport of ice hockey was developed in Canada, most notably in Montreal, where the first indoor hockey game was played on March 3, 1875. Some characteristics of that game, such as the length of the ice rink and the use of a puck, have been retained to this day. Amateur ice hockey leagues began in the 1880s, and professional ice hockey originated around 1900. The Stanley Cup, emblematic of ice hockey club supremacy, was first awarded in 1893 to recognize the Canadian amateur champion and later became the championship trophy of the NHL. In the early 1900s, the Canadian rules were adopted by the Ligue Internationale de Hockey sur Glace, the precursor of the IIHF and the sport was played for the first time at the Olympics during the 1920 Summer Olympics.
In international competitions, the national teams of six countries (the Big Six) predominate: Canada, Czech Republic, Finland, Russia, Sweden and the United States. Of the 69 medals awarded all-time in men's competition at the Olympics, only seven medals were not awarded to one of those countries (or two of their precursors, the Soviet Union for Russia, and Czechoslovakia for the Czech Republic). In the annual Ice Hockey World Championships, 177 of 201 medals have been awarded to the six nations. Teams outside the Big Six have won only five medals in either competition since 1953. The World Cup of Hockey is organized by the National Hockey League and the National Hockey League Players' Association (NHLPA), unlike the annual World Championships and quadrennial Olympic tournament, both run by the International Ice Hockey Federation. World Cup games are played under NHL rules and not those of the IIHF, and the tournament occurs prior to the NHL pre-season, allowing for all NHL players to be available, unlike the World Championships, which overlaps with the NHL's Stanley Cup playoffs. Furthermore, all 12 Women's Olympic and 36 IIHF World Women's Championships medals were awarded to one of these six countries. The Canadian national team or the United States national team have between them won every gold medal of either series.List of A Song of Ice and Fire characters
George R. R. Martin's A Song of Ice and Fire novels feature a sizable cast of characters. The series follows three interwoven plotlines: a dynastic war for control of Westeros by several families; the rising threat of the superhuman Others beyond Westeros' northern border; and the ambition of Daenerys Targaryen, the exiled heir of the previous ruling dynasty. The Great Houses of Westeros represent the Seven Kingdoms forged across the continent: the North, the Iron Islands, the Vale of Arryn, the Westerlands, the Stormlands, the Reach, and Dorne. A massive Wall of ice and old magic separates the Seven Kingdoms from the largely unmapped area in the most northern portion of the continent.
Each chapter is narrated in the third-person limited point of view through the eyes of a single character. Beginning with nine POV characters in A Game of Thrones (1996), a total of 31 such characters have narrated over the course of the first five volumes of the series.N.W.A
N.W.A (an abbreviation for Niggaz Wit Attitudes) was an American hip hop group from Compton, California. They were among the earliest and most significant popularizers and controversial figures of the gangsta rap subgenre, and are widely considered one of the greatest and most influential groups in the history of hip hop music.Active from 1986 to 1991, the rap group endured controversy owing to their music's explicit lyrics which many viewed as being mysogynist, as well as to its glorification of drugs and crime. The group was subsequently banned from many mainstream American radio stations. In spite of this, the group has sold over 10 million units in the United States alone. Drawing on their own experiences of racism and excessive policing, the group made inherently political music. They were known for their deep hatred of the police system, which sparked much controversy over the years.
The original lineup, formed in 1986, consisted of Arabian Prince, Dr. Dre, Eazy-E, and Ice Cube. DJ Yella and MC Ren joined later in 1987. They released their first compilation album as a group in 1987 called N.W.A. and the Posse which peaked at #39 on Billboard magazine's Top R&B/Hip-Hop Albums chart. Arabian Prince eventually left shortly after the release of their debut studio album, Straight Outta Compton, in 1988 and Ice Cube following suit in December 1989. Eazy-E, Ice Cube, MC Ren and Dr. Dre would later become platinum-selling solo artists in the 1990s. Their debut album marked the beginning of the new gangsta rap era as the production and social commentary in their lyrics were revolutionary within the genre. N.W.A's second studio album, Niggaz4Life, was the first hardcore rap album to debut at number one on the Billboard 200 sales charts.Rolling Stone ranked N.W.A number 83 on their list of the "100 Greatest Artists of All Time". In 2016, the group was inducted into the Rock and Roll Hall of Fame, following three previous nominations.National Hockey League
The National Hockey League (NHL; French: Ligue nationale de hockey—LNH) is a professional ice hockey league in North America, currently comprising 31 teams: 24 in the United States and 7 in Canada. The NHL is considered to be the premier professional ice hockey league in the world, and one of the major professional sports leagues in the United States and Canada. The Stanley Cup, the oldest professional sports trophy in North America, is awarded annually to the league playoff champion at the end of each season.
The National Hockey League was organized on November 26, 1917, at the Windsor Hotel in Montreal after the suspension of operations of its predecessor organization, the National Hockey Association (NHA), which had been founded in 1909 in Renfrew, Ontario. The NHL immediately took the NHA's place as one of the leagues that contested for the Stanley Cup in an annual interleague competition before a series of league mergers and folds left the NHL as the only league left competing for the Stanley Cup in 1926.
At its inception, the NHL had four teams—all in Canada, thus the adjective "National" in the league's name. The league expanded to the United States in 1924, when the Boston Bruins joined, and has since consisted of American and Canadian teams. From 1942 to 1967, the league had only six teams, collectively (if not contemporaneously) nicknamed the "Original Six". The NHL added six new teams to double its size at the 1967 NHL expansion. The league then increased to 18 teams by 1974 and 21 teams in 1979. Between 1991 and 2000, the NHL further expanded to 30 teams. It added its 31st team in 2017 and has approved the addition of a 32nd team in 2021.
The league's headquarters have been in New York City since 1989 when the head office moved there from Montreal.After a labour-management dispute that led to the cancellation of the entire 2004–05 season, the league resumed play in 2005–06 under a new collective agreement that included a salary cap. In 2009, the NHL enjoyed record highs in terms of sponsorships, attendance, and television audiences.The International Ice Hockey Federation (IIHF) considers the Stanley Cup to be one of the "most important championships available to the sport". The NHL draws many highly skilled players from all over the world and currently has players from approximately 20 countries. Canadians have historically constituted the majority of the players in the league, with an increasing percentage of American and European players in recent seasons.
The current NHL Champions are the St. Louis Blues, who defeated the Boston Bruins four games to three in the 2019 Stanley Cup Finals.Pleistocene
The Pleistocene ( , often colloquially referred to as the Ice Age) is the geological epoch which lasted from about 2,588,000 to 11,700 years ago, spanning the world's most recent period of repeated glaciations. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the Paleolithic age used in archaeology.
The Pleistocene is the first epoch of the Quaternary Period or sixth epoch of the Cenozoic Era. In the ICS timescale, the Pleistocene is divided into four stages or ages, the Gelasian, Calabrian, Middle Pleistocene (unofficially the 'Chibanian') and Upper Pleistocene (unofficially the 'Tarantian'). In addition to this international subdivision, various regional subdivisions are often used.
Before a change finally confirmed in 2009 by the International Union of Geological Sciences, the time boundary between the Pleistocene and the preceding Pliocene was regarded as being at 1.806 million years Before Present (BP), as opposed to the currently accepted 2.588 million years BP: publications from the preceding years may use either definition of the period.Port
A port is a maritime commercial facility which may comprise one or more wharves where ships may dock to load and discharge passengers and cargo. Although usually situated on a sea coast or estuary, some ports, such as Hamburg, Manchester and Duluth, are many miles inland, with access from the sea via river or canal.
Today, by far the greatest growth in port development is in Asia, the continent with some of the world's largest and busiest ports, such as Singapore and the Chinese ports of Shanghai and Ningbo-Zhoushan.Stanley Cup
The Stanley Cup (French: La Coupe Stanley) is the championship trophy awarded annually to the National Hockey League (NHL) playoff winner. It is the oldest existing trophy to be awarded to a professional sports franchise, and the International Ice Hockey Federation (IIHF) considers it to be one of the "most important championships available to the sport". The trophy was commissioned in 1892 as the Dominion Hockey Challenge Cup and is named after Lord Stanley of Preston, the Governor General of Canada who donated it as an award to Canada's top-ranking amateur ice hockey club. The entire Stanley family supported the sport, the sons and daughters all playing and promoting the game. The first Cup was awarded in 1893 to Montreal Hockey Club, and winners from 1893 to 1914 were determined by challenge games and league play. Professional teams first became eligible to challenge for the Stanley Cup in 1906. In 1915, professional ice hockey organizations National Hockey Association (NHA) and the Pacific Coast Hockey Association (PCHA) reached a gentlemen's agreement in which their respective champions would face each other annually for the Stanley Cup. It was established as the de facto championship trophy of the NHL in 1926 and then the de jure NHL championship prize in 1947.
There are actually three Stanley Cups: the original bowl of the "Dominion Hockey Challenge Cup", the authenticated "Presentation Cup", and the spelling-corrected "Permanent Cup" on display at the Hockey Hall of Fame. The NHL has maintained control over the trophy itself and its associated trademarks; the NHL does not actually own the trophy but uses it by agreement with the two Canadian trustees of the cup. The NHL has registered trademarks associated with the name and likeness of the Stanley Cup, although there has been dispute as to whether the league has the right to own trademarks associated with a trophy that it does not own.The original bowl was made of silver and is 18.5 centimetres (7.28 inches) high and 29 centimetres (11.42 inches) wide. The current Stanley Cup is topped with a copy of the original bowl, made of a silver and nickel alloy. It has a height of 89.54 centimetres (35.25 inches) and weighs 15.5 kilograms (34.5 lb). A new Stanley Cup is not made each year, unlike the trophies awarded by the other major professional sports leagues of North America. The winners originally kept it until a new champion was crowned, but winning teams currently get the Stanley Cup during the summer and a limited number of days during the season. Every year since 1924, a select portion of the winning players, coaches, management, and club staff names are engraved on its bands, which is unusual among trophies. However, there is not enough room to include all the players and non-players, so some names must be omitted. Between 1924 and 1940, a new band was added almost every year that the trophy was awarded, earning the nickname "Stovepipe Cup" due to the unnatural height of all the bands. In 1947, the cup size was reduced, but not all the large rings were the same size. In 1958, the modern one-piece Cup was designed with a five-band barrel which could contain 13 winning teams per band. The oldest band is removed when the bottom band is full and preserved in the Hockey Hall of Fame in order to prevent the Stanley Cup from growing, and a new blank band added to the bottom. It has been referred to as The Cup, Lord Stanley's Cup, The Holy Grail, or facetiously as Lord Stanley's Mug. The Stanley Cup is surrounded by numerous legends and traditions, the oldest of which is the winning team drinking champagne from it.
Since the 1914–15 season, the Cup has been won a combined 103 times by 20 current NHL teams and 5 defunct teams. It was not awarded in 1919 because of a Spanish flu epidemic or in 2005 because of the 2004–05 NHL lockout. It was held by nine different teams between 1893 and 1914. The Montreal Canadiens have won it a record 24 times and are the most recent Canadian-based team to win it, doing so in 1993; while the Detroit Red Wings have won it 11 times, the most of any United States-based NHL team, most recently in 2008.Vanilla Ice
Robert Matthew Van Winkle (born October 31, 1967), known professionally as Vanilla Ice, is an American rapper, actor, and television host. Born in South Dallas, and raised in Texas and South Florida, Ice released his debut album, Hooked, in 1989 on Ichiban Records, before signing a contract with SBK Records, a record label of the EMI Group, which released a reformatted version of the album in 1990 under the title To the Extreme, which contained Ice's best-known hits: "Ice Ice Baby" and a cover of "Play That Funky Music". "Ice Ice Baby" was the first hip hop single to top the Billboard charts.
Although he was successful, Ice later regretted his business arrangements with SBK, which had paid him to adopt a more commercial appearance to appeal to a mass audience and published fabricated biographical information without his knowledge. After surviving a suicide attempt, Ice changed his musical style and lifestyle. While his later, less mainstream albums failed to chart or receive much radio airplay, Ice has had an underground following. In 2009, Ice began hosting The Vanilla Ice Project on DIY Network. His latest album, WTF – Wisdom, Tenacity & Focus, was released in August 2011. After that, Ice signed to Psychopathic Records.Wayne Gretzky
Wayne Douglas Gretzky (; born January 26, 1961) is a Canadian former professional ice hockey player and former head coach. He played 20 seasons in the National Hockey League (NHL) for four teams from 1979 to 1999. Nicknamed "The Great One", he has been called "the greatest hockey player ever" by many sportswriters, players, and the league itself. Gretzky is the leading scorer in NHL history, with more goals and assists than any other player. He garnered more assists than any other player scored total points, and is the only NHL player to total over 200 points in one season – a feat he accomplished four times. In addition, Gretzky tallied over 100 points in 16 professional seasons, 14 of them consecutive. At the time of his retirement in 1999 and persisting through 2017, he holds 61 NHL records: 40 regular season records, 15 playoff records, and six All-Star records.Born and raised in Brantford, Ontario, Canada, Gretzky honed his skills at a backyard rink and regularly played minor hockey at a level far above his peers. Despite his unimpressive stature, strength and speed, Gretzky's intelligence and reading of the game were unrivaled. He was adept at dodging checks from opposing players, and consistently anticipated where the puck was going to be and executed the right move at the right time. Gretzky became known for setting up behind his opponent's net, an area that was nicknamed "Gretzky's office".In 1978, Gretzky signed with the Indianapolis Racers of the World Hockey Association (WHA), where he briefly played before being traded to the Edmonton Oilers. When the WHA folded, the Oilers joined the NHL, where he established many scoring records and led his team to four Stanley Cup championships. Gretzky's trade to the Los Angeles Kings on August 9, 1988, had an immediate impact on the team's performance, eventually leading them to the 1993 Stanley Cup Finals, and he is credited with popularizing hockey in California. Gretzky played briefly for the St. Louis Blues before finishing his career with the New York Rangers. Gretzky captured nine Hart Trophies as the most valuable player, 10 Art Ross Trophies for most points in a season, two Conn Smythe Trophies as playoff MVP and five Lester B. Pearson Awards (now called the Ted Lindsay Award) for most outstanding player as judged by his peers. He won the Lady Byng Memorial Trophy for sportsmanship and performance five times, and often spoke out against fighting in hockey.After his retirement in 1999, Gretzky was immediately inducted into the Hockey Hall of Fame, making him the most recent player to have the waiting period waived. The NHL retired his jersey number 99 league-wide, making him the only player to receive such an honour. Gretzky was one of six players voted to the International Ice Hockey Federation's (IIHF) Centennial All-Star Team. Gretzky became executive director for the Canadian national men's hockey team during the 2002 Winter Olympics, in which the team won a gold medal. In 2000, he became part-owner of the Phoenix Coyotes, and following the 2004–05 NHL lock-out, he became the team's head coach. In 2004, Gretzky was inducted into the Ontario Sports Hall of Fame. In September 2009, following the Phoenix Coyotes' bankruptcy, Gretzky resigned as head coach and relinquished his ownership share. In October 2016, he became partner and vice-chairman of Oilers Entertainment Group.Zdeno Chára
Zdeno Chára (Slovak pronunciation: [ˈzdɛnɔ ˈxaːra]; born 18 March 1977) is a Slovak professional ice hockey defenseman who serves as captain of the Boston Bruins of the National Hockey League (NHL). He won the James Norris Memorial Trophy while playing for the Bruins in the 2008–09 season. Standing at 6 feet 9 inches (2.06 m) tall, Chára is the tallest person ever to play in the NHL. He is also the second European-born and raised captain to win the Stanley Cup (in 2011), and the first born and trained in a country within the Iron Curtain.