In science, buoyancy or upthrust, is an upward force exerted by a fluid that opposes the weight of an immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid, thus the pressure at the bottom of a column of fluid is greater than at the top of the column. Similarly, the pressure at the bottom of an object submerged in a fluid is greater than at the top of the object and this pressure difference results in a net upwards force on the object. For this reason, an object whose density is greater than that of the fluid in which it is submerged tends to sink, If the object is either less dense than the liquid or is shaped appropriately, the force can keep the object afloat. This can occur only in a reference frame, which either has a gravitational field or is accelerating due to a force other than gravity defining a downward direction. In a situation of fluid statics, the net upward force is equal to the magnitude of the weight of fluid displaced by the body.
The center of buoyancy of an object is the centroid of the volume of fluid. Archimedes principle is named after Archimedes of Syracuse, who first discovered this law in 212 B. C, more tersely, Buoyancy = weight of displaced fluid. The weight of the fluid is directly proportional to the volume of the displaced fluid. Thus, among completely submerged objects with equal masses, objects with greater volume have greater buoyancy and this is known as upthrust. Suppose a rocks weight is measured as 10 newtons when suspended by a string in a vacuum with gravity acting upon it, suppose that when the rock is lowered into water, it displaces water of weight 3 newtons. The force it exerts on the string from which it hangs would be 10 newtons minus the 3 newtons of buoyancy force,10 −3 =7 newtons. Buoyancy reduces the apparent weight of objects that have sunk completely to the sea floor and it is generally easier to lift an object up through the water than it is to pull it out of the water. The density of the object relative to the density of the fluid can easily be calculated without measuring any volumes.
Density of object density of fluid = weight weight − apparent immersed weight Example, If you drop wood into water, Example, A helium balloon in a moving car. During a period of increasing speed, the air mass inside the car moves in the direction opposite to the cars acceleration, the balloon is pulled this way. However, because the balloon is buoyant relative to the air, it ends up being pushed out of the way, If the car slows down, the same balloon will begin to drift backward. For the same reason, as the car goes round a curve and this is the equation to calculate the pressure inside a fluid in equilibrium
Ellesmere Island is part of the Qikiqtaaluk Region of the Canadian territory of Nunavut. Lying within the Canadian Arctic Archipelago, it is considered part of the Queen Elizabeth Islands and it comprises an area of 196,235 km2 and the total length of the island is 830 kilometres, making it the worlds tenth largest island and Canadas third largest island. The Arctic Cordillera mountain system covers much of Ellesmere Island, making it the most mountainous in the Canadian Arctic Archipelago, the Arctic willow is the only woody species to grow on Ellesmere Island. The first human inhabitants of Ellesmere Island were small bands drawn to the area for Peary caribou, vikings from the Greenland colonies reached Ellesmere Island, Skraeling Island, and Ruin Island during hunting expeditions and trading with the Inuit groups. Unusual structures on Bache peninsula may be the remains of a late-period Dorset stone longhouse, the first European to sight the island after the height of the Little Ice Age was William Baffin in 1616.
Ellesmere Island was named in 1852 by Edward Inglefields expedition after Francis Egerton, the US expedition led by Adolphus Greely in 1881 crossed the island from east to west, establishing Fort Conger in the northern part of the island. The Greely expedition found fossil forests on Ellesmere Island in the late 1880s, Stenkul Fiord was first explored in 1902 by Per Schei, a member of Otto Sverdrups 2nd Norwegian Polar Expedition. In 1906 Robert Peary led an expedition in northern Ellesmere Island, during Pearys expedition, the Ice Shelf was continuous, a modern estimate is that it covered 8,900 km2. In 2011, Jon Turk and Erik Boomer completed the first known circumnavigation of Ellesmere Island, Ellesmere Island contains Canadas northernmost point, Cape Columbia at 83°6′41″N. Barbeau Peak, the highest mountain in Nunavut is located in the British Empire Range on Ellesmere Island, the most northern mountain range in the world, the Challenger Mountains, is located in the northeast region of the island.
The northern lobe of the island is called Grant Land, in July 2007, a study noted the disappearance of habitat for waterfowl and algae on Ellesmere Island. The researchers noted that In the 1980s they often needed to wear hip waders to make their way to the ponds. while by 2006 the same areas were dry enough to burn. The northwest coast of Ellesmere Island was covered by a massive,500 km long ice shelf until the 20th century. A1986 survey of Canadian ice shelves found that 48 km2 or 3.3 km3 of ice calved from the Milne and Ayles ice shelves between 1959 and 1974. The Ward Hunt Ice Shelf, the largest remaining section of thick landfast sea ice along the coastline of Ellesmere Island. It further decreased by 27% in thickness between 1967 and 1999, Schei and Nathorst described the Paleocene-Eocene fossil forest in the Stenkul Fiord sediments. The Stenkul Fiord site represents a series of deltaic swamp and floodplain forests, the trees stood for at least 400 years. Individual stumps and stems of >1 m diameter were abundant, and are identified as Metasequoia, well preserved Pliocene peats containing abundant vertebrate and plant macrofossils characteristic of a boreal forest have been reported from Strathcona Fiord
Ice is water frozen into a solid state. Depending on the presence of such as particles of soil or bubbles of air. In the Solar System, ice is abundant and occurs naturally from as close to the Sun as Mercury to as far as away the Oort cloud objects, beyond the Solar System, it occurs as interstellar ice. It falls as snowflakes and hail or occurs as frost, icicles or ice spikes, Ice molecules can exhibit up to sixteen different phases that depend on temperature and pressure. When water is cooled rapidly, up to three different types of ice can form depending on the history of its pressure and temperature. When cooled slowly correlated proton tunneling occurs below 20 K giving rise to macroscopic quantum phenomena, virtually all the ice on Earths surface and in its atmosphere is of a hexagonal crystalline structure denoted as ice Ih with minute traces of cubic ice denoted as ice Ic. The most common phase transition to ice Ih occurs when water is cooled below 0°C at standard atmospheric pressure.
It may be deposited directly by water vapor, as happens in the formation of frost, the transition from ice to water is melting and from ice directly to water vapor is sublimation. Ice is used in a variety of ways, including cooling, winter sports, as a naturally occurring crystalline inorganic solid with an ordered structure, ice is considered a mineral. It possesses a regular crystalline structure based on the molecule of water, an unusual property of ice frozen at atmospheric pressure is that the solid is approximately 8. 3% less dense than liquid water. The density of ice is 0.9167 g/cm3 at 0 °C, liquid water is densest, essentially 1.00 g/cm³, at 4 °C and becomes less dense as the water molecules begin to form the hexagonal crystals of ice as the freezing point is reached. This is due to hydrogen bonding dominating the intermolecular forces, which results in a packing of molecules less compact in the solid, density of ice increases slightly with decreasing temperature and has a value of 0.9340 g/cm³ at −180 °C.
When water freezes, it increases in volume and it is a common cause of the flooding of houses when water pipes burst due to the pressure of expanding water when it freezes. The result of this process is that ice floats on liquid water, sufficiently thin ice sheets allow light to pass through while protecting the underside from short-term weather extremes such as wind chill. This creates an environment for bacterial and algal colonies. When ice melts, it absorbs as much energy as it would take to heat an equivalent mass of water by 80 °C, during the melting process, the temperature remains constant at 0 °C. While melting, any energy added breaks the bonds between ice molecules. Energy becomes available to increase the thermal energy only after enough hydrogen bonds are broken that the ice can be considered liquid water, the amount of energy consumed in breaking hydrogen bonds in the transition from ice to water is known as the heat of fusion
Johns Hopkins Glacier
Johns Hopkins Glacier is a 12-mile long glacier located in Glacier Bay National Park and Preserve in the U. S. state of Alaska. It was named after Johns Hopkins University in Baltimore, Maryland in 1893 by Harry Fielding Reid and it is one of the few advancing tidewater glaciers of the Fairweather Range. Access to the face of the glacier is limited to the Johns Hopkins Inlet
IMAX is a motion picture film format and a set of cinema projection standards developed in Canada by Graeme Ferguson, Roman Kroitor, Robert Kerr, and William C. IMAX has the capacity to record and display images of far greater size, since 2002, some feature films have been converted into IMAX format for displaying in IMAX theatres and some have been partially shot in IMAX. IMAX is the most widely used system for special-venue film presentations, as of June 2016, there were 1,102 IMAX theatres in 69 countries. The desire to increase the impact of film has a long history. In 1929, Fox introduced Fox Grandeur, the first 70 mm film format, in the 1950s, the potential of 35 mm film to provide wider projected images was explored in the processes of CinemaScope and VistaVision, following multi-projector systems such as Cinerama. While impressive, Cinerama was difficult to install, during Expo 67 in Montreal, the National Film Board of Canadas In the Labyrinth and Fergusons Man and the Polar Regions both used multi-projector, multi-screen systems.
Each encountered technical difficulties led them to found a company called Multiscreen. As it became clear that a single, large-screen image had more impact than multiple smaller ones and was a viable product direction. An IMAX 3D theatre is in operation near the former Expo 67 site at the Montreal Science Centre in the Port of Old Montreal, tiger Child, the first IMAX film, was demonstrated at Expo 70 in Osaka, Japan. The first permanent IMAX installation was built at the Cinesphere theatre at Ontario Place in Toronto and it debuted in May 1971, showing the film North of Superior. The installation is still in place, Ontario Place is on hiatus for redevelopment, during Expo 74 in Spokane, Washington, an IMAX screen that measured 27 m ×20 m was featured in the US Pavilion. It became the first IMAX Theatre to not be partnered with any brand of movie theaters. About five million visitors viewed the screen, which covered the total visual field when looking directly forward. This created a sensation of motion in most viewers, and motion sickness in some, much to the dismay of the majority of Spokane and the disapproval of the IMAX Corporation itself, it will be demolished to make way for a parking lot.
Another IMAX 3D theater was built in Spokane, not too far from where the original was. However, its screen-size is less than half that of the original, due to protests, the IMAX Corporation has been able to remodel the area with the city, and turn the U. S. Pavilion itself into the first permanent outdoor IMAX screen, the first permanent IMAX Dome installation, the Eugene Heikoff and Marilyn Jacobs Heikoff Dome Theatre at the Reuben H. Fleet Science Center, opened in San Diegos Balboa Park in 1973, the first permanent IMAX 3D theatre was built in Vancouver, British Columbia for Transitions at Expo 86, and was in use until September 30,2009
Ablation is removal of material from the surface of an object by vaporization, chipping, or other erosive processes. Biological ablation is the removal of a structure or functionality. Genetic ablation is another term for gene silencing, in gene expression is abolished through the alteration or deletion of genetic sequence information. In cell ablation, individual cells in a population or culture are destroyed or removed, both can be used as experimental tools, as in loss-of-function experiments. In glaciology and meteorology, ablation—the opposite of accumulation—refers to all processes that remove snow, Ablation refers to the melting of snow or ice that runs off the glacier, sublimation, calving, or erosive removal of snow by wind. Air temperature is typically the dominant control of ablation, with precipitation exercising secondary control, in a temperate climate during ablation season, ablation rates typically average around 2 mm/h. Where solar radiation is the dominant cause of snow ablation, characteristic ablation textures such as suncups, Ablation can refer either to the processes removing ice and snow or to the quantity of ice and snow removed.
Laser ablation is greatly affected by the nature of the material and its ability to absorb energy, since the cornea does not grow back, laser is used to remodel the cornea refractive properties to correct refraction errors, such as astigmatism and hyperopia. Laser ablation is used to remove part of the uterine wall in women with menstruation. Ablative paints are often utilized for this purpose to prevent the dilution or deactivation of the antifouling agent, over time, the paint will slowly decompose in the water, exposing fresh antifouling compounds on the surface. Engineering the antifouling agents and the rate can produce long-lived protection from the deleterious effects of biofouling. In medicine, ablation is the same as removal of a part of biological tissue, surface ablation of the skin can be carried out by chemicals, by lasers, or by electricity. Its purpose is to remove skin spots, aged skin, surface ablation is employed in otolaryngology for several kinds of surgery, such as for snoring.
The term is used in the context of laser ablation. For a laser to ablate tissues, the density or fluence must be high, otherwise thermocoagulation occurs. Rotoablation is a type of arterial cleansing that consists of inserting a tiny, diamond-tipped, the procedure is used in the treatment of coronary heart disease to restore blood flow. Radiofrequency ablation is a method of removing aberrant tissue from within the body via minimally invasive procedures, microwave ablation is similar to RFA but at higher frequency of electromagnetic radiation. Bone marrow ablation is a process whereby the human bone marrow cells are eliminated in preparation for a marrow transplant
Greenland is an autonomous constituent country within the Danish Realm between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for more than a millennium. The majority of its residents are Inuit, whose ancestors began migrating from the Canadian mainland in the 13th century, Greenland is the worlds largest island. Three-quarters of Greenland is covered by the permanent ice sheet outside Antarctica. With a population of about 56,480, it is the least densely populated country in the world, the Arctic Umiaq Line ferry acts as a lifeline for western Greenland, connecting the various cities and settlements. Greenland has been inhabited off and on for at least the last 4,500 years by Arctic peoples whose forebears migrated there from what is now Canada, Norsemen settled the uninhabited southern part of Greenland beginning in the 10th century, and Inuit peoples arrived in the 13th century.
The Norse colonies disappeared in the late 15th century, soon after their demise, beginning in 1499, the Portuguese briefly explored and claimed the island, naming it Terra do Lavrador. In the early 18th century, Scandinavian explorers reached Greenland again, to strengthen trading and power, Denmark-Norway affirmed sovereignty over the island. Greenland was settled by Vikings more than a thousand years ago, Vikings set sail from Greenland and Iceland, discovering North America nearly 500 years before Columbus reached Caribbean islands. Though under continuous influence of Norway and Norwegians, Greenland was not formally under the Norwegian crown until 1262, the Kingdom of Norway was extensive and a military power until the mid-14th century. Thus, the two kingdoms resources were directed at creating Copenhagen, Norway became the weaker part and lost sovereignty over Greenland in 1814 when the union was dissolved. Greenland became a Danish colony in 1814, and was made a part of the Danish Realm in 1953 under the Constitution of Denmark, in 1973, Greenland joined the European Economic Community with Denmark.
However, in a referendum in 1982, a majority of the population voted for Greenland to withdraw from the EEC which was effected in 1985, Greenland contains the worlds largest and most northernly national park, Northeast Greenland National Park. Greenland is divided into four municipalities - Sermersooq, Qaasuitsup and it retains control of monetary policy, providing an initial annual subsidy of DKK3.4 billion, which is planned to diminish gradually over time. Greenland expects to grow its economy based on increased income from the extraction of natural resources, the capital, held the 2016 Arctic Winter Games. At 70%, Greenland has one of the highest shares of renewable energy in the world, the early Viking settlers named the island as Greenland. In the Icelandic sagas, the Norwegian-born Icelander Erik the Red was said to be exiled from Iceland for manslaughter, along with his extended family and his thralls, he set out in ships to explore an icy land known to lie to the northwest. After finding an area and settling there, he named it Grœnland
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 14,000,000 square kilometres, it is the fifth-largest continent, for comparison, Antarctica is nearly twice the size of Australia. About 98% of Antarctica is covered by ice that averages 1.9 km in thickness, Antarctica, on average, is the coldest and windiest continent, and has the highest average elevation of all the continents. Antarctica is a desert, with precipitation of only 200 mm along the coast. The temperature in Antarctica has reached −89.2 °C, though the average for the quarter is −63 °C. Anywhere from 1,000 to 5,000 people reside throughout the year at the research stations scattered across the continent. Organisms native to Antarctica include many types of algae, fungi, protista, where it occurs, is tundra. The continent, remained neglected for the rest of the 19th century because of its hostile environment, lack of easily accessible resources.
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 continents ecozone. Ongoing experiments are conducted by more than 4,000 scientists from many nations, the name Antarctica is the romanised version of the Greek compound word ἀνταρκτική, feminine of ἀνταρκτικός, meaning opposite to the Arctic, opposite to the north. Aristotle wrote in his book Meteorology about an Antarctic region in c.350 B. C, marinus of Tyre reportedly used the name in his unpreserved world map from the 2nd century A. D. Before acquiring its present geographical connotations, the term was used for locations that could be defined as opposite to the north.
For example, the short-lived French colony established in Brazil in the 16th century was called France Antarctique, the first formal use of the name Antarctica as a continental name in the 1890s is attributed to the Scottish cartographer John George Bartholomew. Antarctica has no population and there is no evidence that it was seen by humans until the 19th century. Explorer Matthew Flinders, in particular, has credited with popularising the transfer of the name Terra Australis to Australia. Cook came within about 120 km of the Antarctic coast before retreating in the face of ice in January 1773. The first confirmed sighting of Antarctica can be narrowed down to the crews of ships captained by three individuals, according to various organisations, ships captained by three men sighted Antarctica or its ice shelf in 1820, von Bellingshausen, Edward Bransfield, and Nathaniel Palmer
A calf is the young of domestic cattle. Calves are reared to become adult cattle, or are slaughtered for their meat, called veal, the term calf is used for some other species. Calf is the term used from birth to weaning, when it becomes known as a weaner or weaner calf, the birth of a calf is known as calving. A calf that has lost its mother is an orphan calf, bobby calves are young calves which are to be slaughtered for human consumption. A vealer is a fat calf weighing less than about 330 kg which is at about eight to nine months of age, a young female calf from birth until she has had a calf of her own is called a heifer. In the American Old West, a motherless or small, runty calf was sometimes referred to as a dogie, the term calf is used for some other species. Calves may be produced by means, or by artificial breeding using artificial insemination or embryo transfer. Calves are born after a gestation of nine months and they usually stand within a few minutes of calving, and suckle within an hour.
By a week old the calf is able to follow the mother all the time, some calves are ear tagged soon after birth, especially those that are stud cattle in order to correctly identify their dams, or in areas where tagging is a legal requirement for cattle. A calf must have the very best of everything until it is at least eight months old if it is to reach its maximum potential, typically when the calves are about two months old they are branded, ear marked and vaccinated. The single suckler system of rearing calves is similar to that occurring naturally in wild cattle and this system is commonly used for rearing beef cattle throughout the world. Cows kept on poor forage produce an amount of milk. A calf left with such a mother all the time can easily drink all the milk, leaving none for human consumption. For dairy production under such circumstances, the access to the cow must be limited, for example by penning the calf. In more intensive farming, cows can easily be bred and fed to produce far more milk than one calf can drink.
In the multi-suckler system, several calves are fostered onto one cow in addition to her own, more commonly, calves of dairy cows are fed formula milk from a bottle or bucket from soon after birth. Purebred female calves of cows are reared as replacement dairy cows. Most purebred dairy calves are produced by artificial insemination, by this method each bull can serve very many cows, so only a very few of the purebred dairy male calves are needed to provide bulls for breeding
The Antarctic Peninsula is the northernmost part of the mainland of Antarctica, located at the base of the Southern Hemisphere. At the surface, it is the biggest, most prominent peninsula in Antarctica as it extends 1,300 km from a line between Cape Adams and a point on the south of Eklund Islands. They are joined together by an ice sheet. Tierra del Fuego, the southernmost tip of South America, lies only about 1,000 km away across the Drake Passage, the Antarctic Peninsula is currently dotted with numerous research stations and nations have made multiple claims of sovereignty. The peninsula is part of disputed and overlapping claims by Argentina, none of these claims has international recognition and, under the Antarctic Treaty System, the respective countries do not attempt to enforce their claims. Argentina has the most bases and personnel stationed on the peninsula, the first sighting of the Antarctic Peninsula by Europeans is disputed but apparently occurred in 1820. But the party did not recognize as the mainland what they thought was a covered by small hillocks.
Three days on 30 January 1820, Edward Bransfield and William Smith, with a British expedition, were the first to part of the Antarctic Peninsula. This area was to be called Trinity Peninsula and is the extreme northeast portion of the peninsula, the next confirmed sighting was in 1832 by John Biscoe, a British explorer, who named the northern part of the Antarctic Peninsula as Graham Land. The first European to land on the continent is disputed, a 19th-century seal hunter, John Davis, was almost certainly the first. But, sealers were secretive about their movements and their logbooks were deliberately unreliable, between 1901 and 1904, Otto Nordenskiöld led the Swedish Antarctic Expedition, one of the first expeditions to explore parts of Antarctica. They landed on the Antarctic Peninsula in February 1902, aboard the Antarctica and they were rescued by an Argentine ship. The British Graham Land Expedition between 1934 and 1937 carried out surveys and concluded that Graham Land was not an archipelago but was a peninsula.
This dispute was resolved by making Graham Land the part of the Antarctic Peninsula northward of a line between Cape Jeremy and Cape Agassiz, and Palmer Land the part southward of that line, Palmer Land is named for the United States seal hunter Nathaniel Palmer. In Chile, the peninsula is officially named OHiggins Land, after Bernardo OHiggins, other Spanish-speaking countries call it Península Antártica, among them Argentina. It officially refers to this as Tierra de San Martín, the first Antarctic research stations were established during World War II by a British military operation, Operation Tabarin. The 1950s saw an increase in the number of research bases as Britain, Chile. Meteorology and geology were the research subjects
Jet skis typically can carry 1-2 people seated in a configuration more like a typical bike or motorcycle. It was the first commercially successful personal watercraft in America, having released in 1972. The term is used generically to refer to any type of personal watercraft. Though the proper noun Jet Ski is a trademark of Kawasaki. The Oxford English Dictionary records the term in use in 1961 to describe the aquatic motorbike, U. S. astronaut Alan G. Poindexter died in 2012 due to an accident with a jet ski in Florida
A glacier terminus, toe, or snout, is the end of a glacier at any given point in time. Although glaciers seem motionless to the observer, in reality glaciers are in endless motion, the position of a glacier terminus is impacted by localized or regional temperature change over time. Tracking the change in location of a terminus is a method of monitoring a glaciers movement. The end of the terminus is measured from a fixed position in neighboring bedrock periodically over time. The difference in location of a terminus as measured from this fixed position at different time intervals provides a record of the glaciers change. A similar way of tracking glacier change is comparing photographs of the position at different times. The form of a terminus is determined by many factors. If the glacier is retreating, it is usually mildly sloping in form because a melting glacier tends to assume this shape. The photograph above shows the glacial lakes formed by the glacial termini on the surface of the debris-covered glaciers over the last several decades in the Bhutan-Himalaya region