Lead is a chemical element with symbol Pb and atomic number 82. It is a heavy metal, denser than most common materials. Lead is soft and malleable, has a low melting point; when freshly cut, lead is silvery with a hint of blue. Lead has the highest atomic number of any stable element and three of its isotopes each include a major decay chain of heavier elements. Lead is a unreactive post-transition metal, its weak metallic character is illustrated by its amphoteric nature. Compounds of lead are found in the +2 oxidation state rather than the +4 state common with lighter members of the carbon group. Exceptions are limited to organolead compounds. Like the lighter members of the group, lead tends to bond with itself. Lead is extracted from its ores. Galena, a principal ore of lead bears silver, interest in which helped initiate widespread extraction and use of lead in ancient Rome. Lead production declined after the fall of Rome and did not reach comparable levels until the Industrial Revolution. In 2014, the annual global production of lead was about ten million tonnes, over half of, from recycling.
Lead's high density, low melting point and relative inertness to oxidation make it useful. These properties, combined with its relative abundance and low cost, resulted in its extensive use in construction, batteries and shot, solders, fusible alloys, white paints, leaded gasoline, radiation shielding. In the late 19th century, lead's toxicity was recognized, its use has since been phased out of many applications. However, many countries still allow the sale of products that expose humans to lead, including some types of paints and bullets. Lead is a toxin that accumulates in soft tissues and bones, it acts as a neurotoxin damaging the nervous system and interfering with the function of biological enzymes, causing neurological disorders, such as brain damage and behavioral problems. A lead atom has 82 electrons, arranged in an electron configuration of 4f145d106s26p2; the sum of lead's first and second ionization energies—the total energy required to remove the two 6p electrons—is close to that of tin, lead's upper neighbor in the carbon group.
This is unusual. The similarity of ionization energies is caused by the lanthanide contraction—the decrease in element radii from lanthanum to lutetium, the small radii of the elements from hafnium onwards; this is due to poor shielding of the nucleus by the lanthanide 4f electrons. The sum of the first four ionization energies of lead exceeds that of tin, contrary to what periodic trends would predict. Relativistic effects, which become significant in heavier atoms, contribute to this behavior. One such effect is the inert pair effect: the 6s electrons of lead become reluctant to participate in bonding, making the distance between nearest atoms in crystalline lead unusually long. Lead's lighter carbon group congeners form stable or metastable allotropes with the tetrahedrally coordinated and covalently bonded diamond cubic structure; the energy levels of their outer s- and p-orbitals are close enough to allow mixing into four hybrid sp3 orbitals. In lead, the inert pair effect increases the separation between its s- and p-orbitals, the gap cannot be overcome by the energy that would be released by extra bonds following hybridization.
Rather than having a diamond cubic structure, lead forms metallic bonds in which only the p-electrons are delocalized and shared between the Pb2+ ions. Lead has a face-centered cubic structure like the sized divalent metals calcium and strontium. Pure lead has a silvery appearance with a hint of blue, it tarnishes on contact with moist air and takes on a dull appearance, the hue of which depends on the prevailing conditions. Characteristic properties of lead include high density, malleability and high resistance to corrosion due to passivation. Lead's close-packed face-centered cubic structure and high atomic weight result in a density of 11.34 g/cm3, greater than that of common metals such as iron and zinc. This density is the origin of the idiom to go over like a lead balloon; some rarer metals are denser: tungsten and gold are both at 19.3 g/cm3, osmium—the densest metal known—has a density of 22.59 g/cm3 twice that of lead. Lead is a soft metal with a Mohs hardness of 1.5. It is somewhat ductile.
The bulk modulus of lead—a measure of its ease of compressibility—is 45.8 GPa. In comparison, that of aluminium is 75.2 GPa. Lead's tensile strength, at 12–17 MPa, is low; the melting point of lead—at 327.5 °C —is low compared to most metals. Its boiling point of 1749 °C is the lowest among the carbon group elements; the electrical resistivity of lead at 20 °C is 192 nanoohm-meters an order of magnitude higher than those of other industrial metals. Lead is a superconductor at temperatures lower than 7.19 K.
Glamorgan, or sometimes Glamorganshire, is one of the thirteen historic counties of Wales and a former administrative county of Wales. It was an early medieval petty kingdom of varying boundaries known as Glywysing until taken over by the Normans as a lordship. Glamorgan is latterly represented by the three preserved counties of Mid Glamorgan, South Glamorgan and West Glamorgan; the name survives in that of Vale of Glamorgan, a county borough. Although a rural and pastoral area of little value, the area that became known as Glamorgan was a conflict point between the Norman lords and the Welsh princes, with the area being defined by a large concentration of castles. After falling under English rule in the 16th century, Glamorgan became a more stable county, exploited its natural resources to become an important part of the Industrial Revolution. Glamorgan was the most populous and industrialised county in Wales, was once called the "crucible of the Industrial Revolution," as it contained the world centres of three metallurgical industries and its rich resources of coal.
The county of Glamorgan comprises several distinct regions: the industrial valleys, the agricultural Vale of Glamorgan, the scenic Gower Peninsula. The county is bounded to the north by Brecknockshire, east by Monmouthshire, south by the Bristol Channel, west by Carmarthenshire and Carmarthen Bay, its total area is 2,100 km2, the total population of the three preserved counties of Glamorgan in 1991 was 1,288,309. Glamorgan contains two cities, the county town and from 1955 the capital city of Wales, Swansea; the highest point in the county is Craig y Llyn, situated near the village of Rhigos in the Cynon Valley. Glamorgan's terrain has been inhabited by humankind for over 200,000 years. Climate fluctuation caused the formation and reformation of glaciers which, in turn, caused sea levels to rise and fall. At various times life has flourished, at others the area is to have been uninhabitable. Evidence of the presence of Neanderthals has been discovered on the Gower Peninsula. Whether they remained in the area during periods of extreme cold is unclear.
Sea levels have been 150 metres lower and 8 metres higher than at present, resulting in significant changes to the coastline during this period. Archaeological evidence shows; the oldest known human burial in Great Britain – the Red Lady of Paviland – was discovered in a coastal cave between Port Eynon and Rhossili, on the Gower Peninsula. The'lady' has been radiocarbon dated to c. 29,000 years before present – during the Late Pleistocene – at which time the cave overlooked an area of plain, some miles from the sea. From the end of the last ice age Mesolithic hunter-gatherers began to migrate to the British Peninsula – through Doggerland – from the European mainland. Archaeologist Stephen Aldhouse-Green notes that while Wales has a "multitude" of Mesolithic sites, their settlements were "focused on the coastal plains", the uplands were "exploited only by specialist hunting groups". Human lifestyles in North-West Europe changed around 6000 BP, they cleared the forests to establish pasture and to cultivate the land and developed new technologies such as ceramics and textile production.
A tradition of long barrow construction began in continental Europe during the 7th millennium BP – the free standing megalithic structures supporting a sloping capstone. Nineteen Neolithic chambered five possible henges have been identified in Glamorgan; these megalithic burial chambers, or cromlechi, were built between 6000 and 5000 BP, during the early Neolithic period, the first of them about 1500 years before either Stonehenge or the Egyptian Great Pyramid of Giza was completed. Two major groups of Neolithic architectural traditions are represented in the area: portal dolmens; such massive constructions would have needed a large labour force – up to 200 men – suggestive of large communities nearby. Archaeological evidence from some Neolithic sites has shown the continued use of cromlechi in the Bronze Age; the Bronze Age – defined by the use of metal – has made a lasting impression on the area. Over six hundred Bronze Age barrows and cairns, of various types, have been identified all over Glamorgan.
Other technological innovations – including the wheel. Deforestation continued to the more remote areas as a warmer climate allowed the cultivation of upland areas. By 4000 BP people had begun to bury, or cremate their dead in individual cists, beneath a mound of earth known as a round barrow. From c. 3350 BP, a worsening climate began to make agriculture unsustainable in upland areas. The resulting population pressures appear to have led to co
Swansea University is a public research university located in Swansea, United Kingdom. It was chartered as University College of Swansea in 1920, as the fourth college of the University of Wales. In 1996, it changed its name to the University of Wales Swansea following structural changes within the University of Wales; the title of Swansea University was formally adopted on 1 September 2007 when the University of Wales became a non-membership confederal institution and the former members became universities in their own right. Swansea University has 7 colleges spread across its two campuses which are located on the coastline of Swansea Bay; the Singleton Park Campus is set in the grounds of Singleton Park to the west of Swansea city centre. The £450 million Bay Campus, which opened in September 2015, is located adjacent to Jersey Marine Beach to the east of Swansea city centre, it is the third largest university in Wales in terms of number of students. It offers about 330 undergraduate courses and 120 post-graduate courses to 19,160 undergraduate and postgraduate students.
In 2014 Swansea was named University of the Year in the WhatUni.com Student Choice Awards and shortlisted in the same category in the Times Higher Education awards. In 2016, Swansea University was named as the best university in Wales by The Times and The Sunday Times Good University Guide 2017 League Table, it was awarded the inaugural Welsh University of the Year title. In 2017, Hillary Rodham Clinton received an honorary doctorate at Swansea University and unveiled a commemorative stone to mark the renaming of the College of Law to the Hillary Rodham Clinton School of Law; the University College, was established in 1920, opening its doors on 5 October. At the time, it was the youngest of the four colleges of the University of Wales, it was established on the recommendations of a Royal Commission set up in 1916. The college was founded on what were perceived as the needs and the wants of the local area, Swansea's main industries in particular; the Park Campus houses the oldest parts of the university's estate, including Singleton Abbey, a large eighteenth-century mansion, the ancestral home of the Vivian family, having been bought by the prominent industrialist, John Henry Vivian.
Swansea University's foundation stone was laid in 1920 by King George V in July 1920, welcoming 89 students, of whom eight were female. Subjects taught from the beginning of the College were the Sciences, Mathematics and Engineering; the professors were A. R. Richardson, E. J. Evans, J. E. Coates, A. E. Trueman, C. A. Edwards and F. Bacon; the university was granted a coat of arms by the College of Heralds in 1921 with the motto Gweddw Crefft Heb Ei Dawn, translated as Technical Skill is Bereft Without Culture. Arts subjects were not taught in 1920, but started in the following'session', 1921–22; the first professors in those initial departments were D. Emrys Evans, W. D. Thomas, Henry Lewis, E. Ernest Hughes, F. A. Cavenagh and Mary Williams. Williams was the first woman to be appointed to a Chair in the United Kingdom; this met with some reaction from senior men at the College, one of whom she would marry. Saunders Lewis, the well-known Welsh language writer and activist, became a member of staff in 1922 although he ran up against controversy in 1936/37 for trying to set fire to a Royal Air Force bombing school on the Llyn Peninsula.
He was sent to prison for nine months. When Singleton Abbey and its surrounding land was handed to the college in 1923, Arts subjects were moved there from the College's temporary site in Mount Pleasant. Student numbers remained small until the Second World War. Swansea acquired departments of Philosophy 1925, German in 1931, economics in 1937, Social Policy in 1947, Political Theory and Government in 1954 – the same year that a civil engineering and a Geography department were added. In 1961 Swansea became a centre for Russian and East European Studies, whilst Italian and Spanish joined the Department of French. There were many notable staff members at the University in the period, including the long-serving female professor of Botany, Florence Mockeridge. Another was Professor Glanmor Williams who retired in 1982. Other well-known staff members were the author of novels such as Lucky Jim and That Uncertain Feeling, Kingsley Amis, who lectured in English in the 1950s and early 1960s. In 1947, John Fulton, Baron Fulton, the University Principal, had designs on creating the UK's first contained university campus.
Located in the vast expanse of Singleton Park, the university only had 2 permanent buildings. The 1960s saw the university embark on a large campus development programme, aiming to fulfill Fulton's plan of becoming a self-contained community within the city. Along with new halls of residence, a Maths and Science Tower was built, with College House – renamed Fulton House. For most of its history, Swansea University operated from the Singleton Park Campus. However, owing to rapid expansion, the university developed a 65-acre, £450 million beachfront science and innovation Bay Campus which opened in September 2015. Since 2015, Swansea University has operated as a dual-campus university with the'Park Campus' located in its traditional Singleton Park grounds, the Bay Campus, at Crymlyn Burrows; the Bay campus has been developed on a 65
Africa is the world's second largest and second most-populous continent, being behind Asia in both categories. At about 30.3 million km2 including adjacent islands, it covers 6% of Earth's total surface area and 20% of its land area. With 1.2 billion people as of 2016, it accounts for about 16% of the world's human population. The continent is surrounded by the Mediterranean Sea to the north, the Isthmus of Suez and the Red Sea to the northeast, the Indian Ocean to the southeast and the Atlantic Ocean to the west; the continent includes various archipelagos. It contains 54 recognised sovereign states, nine territories and two de facto independent states with limited or no recognition; the majority of the continent and its countries are in the Northern Hemisphere, with a substantial portion and number of countries in the Southern Hemisphere. Africa's average population is the youngest amongst all the continents. Algeria is Africa's largest country by area, Nigeria is its largest by population. Africa central Eastern Africa, is accepted as the place of origin of humans and the Hominidae clade, as evidenced by the discovery of the earliest hominids and their ancestors as well as ones that have been dated to around 7 million years ago, including Sahelanthropus tchadensis, Australopithecus africanus, A. afarensis, Homo erectus, H. habilis and H. ergaster—the earliest Homo sapiens, found in Ethiopia, date to circa 200,000 years ago.
Africa encompasses numerous climate areas. Africa hosts a large diversity of ethnicities and languages. In the late 19th century, European countries colonised all of Africa. African nations cooperate through the establishment of the African Union, headquartered in Addis Ababa. Afri was a Latin name used to refer to the inhabitants of then-known northern Africa to the west of the Nile river, in its widest sense referred to all lands south of the Mediterranean; this name seems to have referred to a native Libyan tribe, an ancestor of modern Berbers. The name had been connected with the Phoenician word ʿafar meaning "dust", but a 1981 hypothesis has asserted that it stems from the Berber word ifri meaning "cave", in reference to cave dwellers; the same word may be found in the name of the Banu Ifran from Algeria and Tripolitania, a Berber tribe from Yafran in northwestern Libya. Under Roman rule, Carthage became the capital of the province it named Africa Proconsularis, following its defeat of the Carthaginians in the Third Punic War in 146 BC, which included the coastal part of modern Libya.
The Latin suffix -ica can sometimes be used to denote a land. The Muslim region of Ifriqiya, following its conquest of the Byzantine Empire's Exarchatus Africae preserved a form of the name. According to the Romans, Africa lay to the west of Egypt, while "Asia" was used to refer to Anatolia and lands to the east. A definite line was drawn between the two continents by the geographer Ptolemy, indicating Alexandria along the Prime Meridian and making the isthmus of Suez and the Red Sea the boundary between Asia and Africa; as Europeans came to understand the real extent of the continent, the idea of "Africa" expanded with their knowledge. Other etymological hypotheses have been postulated for the ancient name "Africa": The 1st-century Jewish historian Flavius Josephus asserted that it was named for Epher, grandson of Abraham according to Gen. 25:4, whose descendants, he claimed, had invaded Libya. Isidore of Seville in his 7th-century Etymologiae XIV.5.2. Suggests "Africa comes from the Latin aprica, meaning "sunny".
Massey, in 1881, stated that Africa is derived from the Egyptian af-rui-ka, meaning "to turn toward the opening of the Ka." The Ka is the energetic double of every person and the "opening of the Ka" refers to a womb or birthplace. Africa would be, for the Egyptians, "the birthplace." Michèle Fruyt in 1976 proposed linking the Latin word with africus "south wind", which would be of Umbrian origin and mean "rainy wind". Robert R. Stieglitz of Rutgers University in 1984 proposed: "The name Africa, derived from the Latin *Aphir-ic-a, is cognate to Hebrew Ophir." Ibn Khallikan and some other historians claim that the name of Africa came from a Himyarite king called Afrikin ibn Kais ibn Saifi called "Afrikus son of Abrahah" who subdued Ifriqiya. Africa is considered by most paleoanthropologists to be the oldest inhabited territory on Earth, with the human species originating from the continent. During the mid-20th century, anthropologists discovered many fossils and evidence of human occupation as early as 7 million years ago.
Fossil remains of several species of early apelike humans thought to have evolved into modern man, such as Australopithecus afarensis (radiometrically dated to 3.9–3.0 million years BP, Paranthropus boisei and Homo ergaster have been discovered. After the evolution of Homo sapiens sapiens 150,000 to 100,000 years BP in Africa, the continent was populated by groups of hunter-gatherers; these first modern humans left Africa and populated the rest of the globe during the Out of Africa II migration dated to 50,000 years BP, exiting the continent eith
Swansea Metropolitan University
Swansea Metropolitan University is a former university based in Swansea, Wales, UK. The university merged with, became a constituent campus of, the University of Wales Trinity Saint David on 1 August 2013. Employing more than 500 staff and teaching over 6,000 students, the Swansea Metropolitan University grew out of the three former Swansea colleges of Art, Teacher Education, Technology which were founded in 1853, 1872 and 1897 and merged in 1976 to form a centre for the delivery of vocational higher education. For most of the 20th century there were – in addition to Swansea University – three separate further educational institutions serving the city of Swansea: the Swansea School of Art and Crafts. Swansea Training College, funded by Rose Mary Crawshay was the first place in Wales where women could train as teachers. During this time, the School of Art and Crafts was based on Alexandra Road, not far from its present location at the bottom of Mount Pleasant Hill opposite Swansea Central Police Station.
The former College of Education was based in the Townhill area of the city where the Metropolitan University's teaching and humanities courses were taught before relocating to the new university development. Swansea Technical College based in Mount Pleasant, was a well known and respected supplier of vocational qualifications. In 1976 the three institutions came together to form the West Glamorgan Institute of Higher Education. In 1992 the institution was renamed Swansea Institute of Higher Education and became an independent Higher Education Corporation away from local authority control. In 2008 and following a successful two-year inspection, the Privy Council gave permission for the institution to be renamed Swansea Metropolitan University. Despite these radical changes, the university has stayed close to its roots, with the three founder institutions still reflected in the four Faculties that make up the university today. There has been a change in the make-up of the institution over the past half century, moving from three separate establishments offering few higher education programmes, to a university that has now close to 7,000 students and is an established and respected provider of undergraduate and research qualifications, as well as professional programmes.
Yet, at the same time, it has stayed a vocationally driven, industry-focused university, serving the local and wider community beyond. Despite being an institution that focuses on teaching, sixty per cent of the university's research work was rated as being of'international significance', in some cases'world leading' in the 2008 Research Assessment Exercise, with particular strengths in art and design and engineering. Both Townhill and Mount pleasant campuses have now closed due to the university relocating to a new redevelopment based in SA1 waterfront. Swansea Metropolitan University had four faculties: The Faculty of Applied Design and Engineering taught skills for engineering, construction, industrial design, the creative industries. Schools: Engineering Architecture and Built Environment Applied Computing Based in the redeveloped former Dynevor Grammar School, the school is now known as Swansea College of Art a constituent campus of the University of Wales Trinity Saint David. Schools: School of Visual Communication School of Fine Art & Photography School of Design & Applied Arts School of Film & Digital Media Formerly Based on Swansea Metropolitan University’s Townhill campus.
The Faculty of Humanities provided teacher training and has an extensive range of undergraduate and postgraduate teaching programmes and has expanded to include courses in performance and literature and psychology. The Facility of Humanities moved from the university Townhill Campus to SA1 Waterfront campus due to the university closing Townhill Campus; the campus was to be sold to developers. Schools: School of Education School of Social Sciences and Performing Arts Based on University of Wales Trinity Saint David, Business campus, High Street Swansea, it had a portfolio of programmes which includes business and tourism, public services and health and social care. Schools: Swansea Business School School of Leisure and Sport School of Public Service Leadership List of universities in Wales
Zinc is a chemical element with symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. In some respects zinc is chemically similar to magnesium: both elements exhibit only one normal oxidation state, the Zn2+ and Mg2+ ions are of similar size. Zinc has five stable isotopes; the most common zinc ore is sphalerite, a zinc sulfide mineral. The largest workable lodes are in Australia and the United States. Zinc is refined by froth flotation of the ore and final extraction using electricity. Brass, an alloy of copper and zinc in various proportions, was used as early as the third millennium BC in the Aegean, the United Arab Emirates, Kalmykia and Georgia, the second millennium BC in West India, Iran, Syria and Israel/Palestine. Zinc metal was not produced on a large scale until the 12th century in India, though it was known to the ancient Romans and Greeks; the mines of Rajasthan have given definite evidence of zinc production going back to the 6th century BC. To date, the oldest evidence of pure zinc comes from Zawar, in Rajasthan, as early as the 9th century AD when a distillation process was employed to make pure zinc.
Alchemists burned zinc in air to form what they called "philosopher's wool" or "white snow". The element was named by the alchemist Paracelsus after the German word Zinke. German chemist Andreas Sigismund Marggraf is credited with discovering pure metallic zinc in 1746. Work by Luigi Galvani and Alessandro Volta uncovered the electrochemical properties of zinc by 1800. Corrosion-resistant zinc plating of iron is the major application for zinc. Other applications are in electrical batteries, small non-structural castings, alloys such as brass. A variety of zinc compounds are used, such as zinc carbonate and zinc gluconate, zinc chloride, zinc pyrithione, zinc sulfide, dimethylzinc or diethylzinc in the organic laboratory. Zinc is an essential mineral, including to postnatal development. Zinc deficiency affects about two billion people in the developing world and is associated with many diseases. In children, deficiency causes growth retardation, delayed sexual maturation, infection susceptibility, diarrhea.
Enzymes with a zinc atom in the reactive center are widespread in biochemistry, such as alcohol dehydrogenase in humans. Consumption of excess zinc may cause ataxia and copper deficiency. Zinc is a bluish-white, diamagnetic metal, though most common commercial grades of the metal have a dull finish, it is somewhat less dense than iron and has a hexagonal crystal structure, with a distorted form of hexagonal close packing, in which each atom has six nearest neighbors in its own plane and six others at a greater distance of 290.6 pm. The metal is hard and brittle at most temperatures but becomes malleable between 100 and 150 °C. Above 210 °C, the metal can be pulverized by beating. Zinc is a fair conductor of electricity. For a metal, zinc has low melting and boiling points; the melting point is the lowest of all the d-block metals aside from cadmium. Many alloys contain zinc, including brass. Other metals long known to form binary alloys with zinc are aluminium, bismuth, iron, mercury, tin, cobalt, nickel and sodium.
Although neither zinc nor zirconium are ferromagnetic, their alloy ZrZn2 exhibits ferromagnetism below 35 K. A bar of zinc generates a characteristic sound when bent, similar to tin cry. Zinc makes up about 75 ppm of Earth's crust. Soil contains zinc in 5–770 ppm with an average 64 ppm. Seawater has only 30 ppb and the atmosphere, 0.1–4 µg/m3. The element is found in association with other base metals such as copper and lead in ores. Zinc is a chalcophile, meaning the element is more to be found in minerals together with sulfur and other heavy chalcogens, rather than with the light chalcogen oxygen or with non-chalcogen electronegative elements such as the halogens. Sulfides formed as the crust solidified under the reducing conditions of the early Earth's atmosphere. Sphalerite, a form of zinc sulfide, is the most mined zinc-containing ore because its concentrate contains 60–62% zinc. Other source minerals for zinc include smithsonite, hemimorphite and sometimes hydrozincite. With the exception of wurtzite, all these other minerals were formed by weathering of the primordial zinc sulfides.
Identified world zinc resources total about 1.9–2.8 billion tonnes. Large deposits are in Australia and the United States, with the largest reserves in Iran; the most recent estimate of reserve base for zinc was made in 2009 and calculated to be 480 Mt. Zinc reserves, on the other hand, are geologically identified ore bodies whose suitability for recovery is economically based at the time of determination. Since exploration and mine development is an ongoing process, the amount of zinc reserves is not a fixed number and sustainability of zinc ore supplies cannot be judged by extrapolating the combined mine life of today's zinc mines; this concept is well supported by data from the United States Geol
The petroleum industry known as the oil industry or the oil patch, includes the global processes of exploration, refining and marketing of petroleum products. The largest volume products of the industry are fuel gasoline. Petroleum is the raw material for many chemical products, including pharmaceuticals, fertilizers, synthetic fragrances, plastics; the extreme monetary value of oil and its products has led to it being known as "black gold". The industry is divided into three major components: upstream and downstream. Petroleum is vital to many industries, is necessary for the maintenance of industrial civilization in its current configuration, making it a critical concern for many nations. Oil accounts for a large percentage of the world’s energy consumption, ranging from a low of 32% for Europe and Asia, to a high of 53% for the Middle East. Other geographic regions' consumption patterns are as follows: South and Central America and North America; the world consumes 30 billion barrels of oil per year, with developed nations being the largest consumers.
The United States consumed 25% of the oil produced in 2007. The production, distribution and retailing of petroleum taken as a whole represents the world's largest industry in terms of dollar value. Governments such as the United States government provide a heavy public subsidy to petroleum companies, with major tax breaks at every stage of oil exploration and extraction, including the costs of oil field leases and drilling equipment. In recent years, enhanced oil recovery techniques — most notably multi-stage drilling and hydraulic fracturing — have moved to the forefront of the industry as this new technology plays a crucial and controversial role in new methods of oil extraction. Petroleum is a occurring liquid found in rock formations, it consists of a complex mixture of hydrocarbons of various molecular weights, plus other organic compounds. It is accepted that oil is formed from the carbon rich remains of ancient plankton after exposure to heat and pressure in Earth's crust over hundreds of millions of years.
Over time, the decayed residue was covered by layers of mud and silt, sinking further down into Earth’s crust and preserved there between hot and pressured layers transforming into oil reservoirs. Petroleum in an unrefined state has been utilized by humans for over 5000 years. Oil in general has been used since early human history to keep fires ablaze and in warfare, its importance to the world economy however, evolved with whale oil being used for lighting in the 19th century and wood and coal used for heating and cooking well into the 20th century. Though the Industrial Revolution generated an increasing need for energy, this was met by coal, from other sources including whale oil. However, when it was discovered that kerosene could be extracted from crude oil and used as a lighting and heating fuel, the demand for petroleum increased and by the early twentieth century had become the most valuable commodity traded on world markets. Imperial Russia doubled its output by mid-century. After oil drilling began in what is now Azerbaijan in 1846 in Baku, two large pipelines were built in the Russian Empire: the 833 km long pipeline to transport oil from the Caspian to the Black Sea port of Batum, completed in 1906, the 162 km long pipeline to carry oil from Chechnya to the Caspian.
Batum is renamed to Batumi in 1936. At the turn of the 20th century, Imperial Russia's output of oil entirely from the Apsheron Peninsula, accounted for half of the world's production and dominated international markets. Nearly 200 small refineries operated in the suburbs of Baku by 1884; as a side effect of these early developments, the Apsheron Peninsula emerged as the world's "oldest legacy of oil pollution and environmental negligence". In 1846, Baku the first well drilled with percussion tools to a depth of 21 meters for oil exploration. In 1878, Ludvig Nobel and his Branobel company "revolutionized oil transport" by commissioning the first oil tanker and launching it on the Caspian Sea. Samuel Kier established America's first oil refinery in Pittsburgh on Seventh avenue near Grant Street, in 1853. One of the first modern oil refineries were built by Ignacy Łukasiewicz near Jasło, Poland in 1854–56; these were small, as demand for refined fuel was limited. The refined products were used in artificial asphalt, machine oil and lubricants, in addition to Łukasiewicz's kerosene lamp.
As kerosene lamps gained popularity, the refining industry grew in the area. The first commercial oil well in Canada became operational in 1858 at Ontario. Businessman James Miller Williams dug several wells between 1855 and 1858 before discovering a rich reserve of oil four metres below ground. Williams extracted 1.5 million litres of crude oil by 1860, refining much of it into kerosene lamp oil. Some historians challenge Canada’s claim to North America’s first oil field, arguing that Pennsylvania’s famous Drake Well was the continent’s first, but there is evidence to support Williams, not least of, that the Drake well did not come into production until August 28, 1859. The controversial point might be that Williams found oil above bedrock while Edwin Drake’s well located oil within a bedrock reservoir; the discovery at Oil Springs touched off an oil boom which brought hundreds of speculators and workers to the area. Canada's first gusher (fl