Paris is the capital and most populous city of France, with an area of 105 square kilometres and an official estimated population of 2,140,526 residents as of 1 January 2019. Since the 17th century, Paris has been one of Europe's major centres of finance, commerce, fashion and the arts; the City of Paris is the centre and seat of government of the Île-de-France, or Paris Region, which has an estimated official 2019 population of 12,213,364, or about 18 percent of the population of France. The Paris Region had a GDP of €681 billion in 2016, accounting for 31 percent of the GDP of France, was the 5th largest region by GDP in the world. According to the Economist Intelligence Unit Worldwide Cost of Living Survey in 2018, Paris was the second most expensive city in the world, after Singapore, ahead of Zurich, Hong Kong and Geneva. Another source ranked Paris as most expensive, on a par with Singapore and Hong-Kong, in 2018; the city is a major rail and air-transport hub served by two international airports: Paris-Charles de Gaulle and Paris-Orly.
Opened in 1900, the city's subway system, the Paris Métro, serves 5.23 million passengers daily, is the second busiest metro system in Europe after Moscow Metro. Gare du Nord is the 24th busiest railway station in the world, the first located outside Japan, with 262 million passengers in 2015. Paris is known for its museums and architectural landmarks: the Louvre was the most visited art museum in the world in 2018, with 10.2 million visitors. The Musée d'Orsay and Musée de l'Orangerie are noted for their collections of French Impressionist art, the Pompidou Centre Musée National d'Art Moderne has the largest collection of modern and contemporary art in Europe; the historical district along the Seine in the city centre is classified as a UNESCO Heritage Site. Popular landmarks in the centre of the city include the Cathedral of Notre Dame de Paris and the Gothic royal chapel of Sainte-Chapelle, both on the Île de la Cité. Paris received 23 million visitors in 2017, measured by hotel stays, with the largest numbers of foreign visitors coming from the United States, the UK, Germany and China.
It was ranked as the third most visited travel destination in the world in 2017, after Bangkok and London. The football club Paris Saint-Germain and the rugby union club Stade Français are based in Paris; the 80,000-seat Stade de France, built for the 1998 FIFA World Cup, is located just north of Paris in the neighbouring commune of Saint-Denis. Paris hosts the annual French Open Grand Slam tennis tournament on the red clay of Roland Garros. Paris will host the 2024 Summer Olympics; the 1938 and 1998 FIFA World Cups, the 2007 Rugby World Cup, the 1960, 1984, 2016 UEFA European Championships were held in the city and, every July, the Tour de France bicycle race finishes there. The name "Paris" is derived from the Celtic Parisii tribe; the city's name is not related to the Paris of Greek mythology. Paris is referred to as the City of Light, both because of its leading role during the Age of Enlightenment and more because Paris was one of the first large European cities to use gas street lighting on a grand scale on its boulevards and monuments.
Gas lights were installed on the Place du Carousel, Rue de Rivoli and Place Vendome in 1829. By 1857, the Grand boulevards were lit. By the 1860s, the boulevards and streets of Paris were illuminated by 56,000 gas lamps. Since the late 19th century, Paris has been known as Panam in French slang. Inhabitants are known in French as Parisiens, they are pejoratively called Parigots. The Parisii, a sub-tribe of the Celtic Senones, inhabited the Paris area from around the middle of the 3rd century BC. One of the area's major north–south trade routes crossed the Seine on the île de la Cité; the Parisii minted their own coins for that purpose. The Romans began their settlement on Paris' Left Bank; the Roman town was called Lutetia. It became a prosperous city with a forum, temples, an amphitheatre. By the end of the Western Roman Empire, the town was known as Parisius, a Latin name that would become Paris in French. Christianity was introduced in the middle of the 3rd century AD by Saint Denis, the first Bishop of Paris: according to legend, when he refused to renounce his faith before the Roman occupiers, he was beheaded on the hill which became known as Mons Martyrum "Montmartre", from where he walked headless to the north of the city.
Clovis the Frank, the first king of the Merovingian dynasty, made the city his capital from 508. As the Frankish domination of Gaul began, there was a gradual immigration by the Franks to Paris and the Parisian Francien dialects were born. Fortification of the Île-de-la-Citie failed to avert sacking by Vikings in 845, but Paris' strategic importance—with its bridges prevent
The Avogadro constant, named after scientist Amedeo Avogadro, is the number of constituent particles molecules, atoms or ions that are contained in the amount of substance given by one mole. It is the proportionality factor that relates the molar mass of a substance to the mass of a sample, is designated with the symbol NA or L, has the value 6.022140857×1023 mol−1 in the International System of Units. Previous definitions of chemical quantity involved the Avogadro number, a historical term related to the Avogadro constant, but defined differently: the Avogadro number was defined by Jean Baptiste Perrin as the number of atoms in one gram-molecule of atomic hydrogen, meaning one gram of hydrogen; this number is known as Loschmidt constant in German literature. The constant was redefined as the number of atoms in 12 grams of the isotope carbon-12, still generalized to relate amounts of a substance to their molecular weight. For instance, the number of nucleons in one mole of any sample of ordinary matter is, to a first approximation, 6×1023 times its molecular weight.
12 grams of 12C, with the mass number 12, has a similar number of carbon atoms, 6.022×1023. The Avogadro number is a dimensionless quantity, has the same numerical value of the Avogadro constant when given in base units. In contrast, the Avogadro constant has the dimension of reciprocal amount of substance; the Avogadro constant can be expressed as 0.6023... mL⋅mol−1⋅Å−3, which can be used to convert from volume per molecule in cubic ångströms to molar volume in millilitres per mole. Pending revisions in the base set of SI units necessitated redefinitions of the concepts of chemical quantity; the Avogadro number, its definition, was deprecated in favor of the Avogadro constant and its definition. Based on measurements made through the middle of 2017 which calculated a value for the Avogadro constant of NA = 6.022140758×1023 mol−1, the redefinition of SI units is planned to take effect on 20 May 2019. The value of the constant will be fixed to 6.02214076×1023 mol−1. The Avogadro constant is named after the early 19th-century Italian scientist Amedeo Avogadro, who, in 1811, first proposed that the volume of a gas is proportional to the number of atoms or molecules regardless of the nature of the gas.
The French physicist Jean Perrin in 1909 proposed naming the constant in honor of Avogadro. Perrin won the 1926 Nobel Prize in Physics for his work in determining the Avogadro constant by several different methods; the value of the Avogadro constant was first indicated by Johann Josef Loschmidt, who in 1865 estimated the average diameter of the molecules in the air by a method, equivalent to calculating the number of particles in a given volume of gas. This latter value, the number density n0 of particles in an ideal gas, is now called the Loschmidt constant in his honor, is related to the Avogadro constant, NA, by n 0 = p 0 N A R T 0, where p0 is the pressure, R is the gas constant, T0 is the absolute temperature; the connection with Loschmidt is the origin of the symbol L sometimes used for the Avogadro constant, German-language literature may refer to both constants by the same name, distinguished only by the units of measurement. Accurate determinations of the Avogadro constant require the measurement of a single quantity on both the atomic and macroscopic scales using the same unit of measurement.
This became possible for the first time when American physicist Robert Millikan measured the charge on an electron in 1910. The electric charge per mole of electrons is a constant called the Faraday constant and had been known since 1834 when Michael Faraday published his works on electrolysis. By dividing the charge on a mole of electrons by the charge on a single electron the value of the Avogadro number is obtained. Since 1910, newer calculations have more determined the values for the Faraday constant and the elementary charge. Perrin proposed the name Avogadro's number to refer to the number of molecules in one gram-molecule of oxygen, this term is still used in introductory works; the change in name to Avogadro constant came with the introduction of the mole as a base unit in the International System of Units in 1971, which regarded amount of substance as an independent dimension of measurement. With this recognition, the Avogadro constant was no longer a pure number, but had a unit of measurement, the reciprocal mole.
While it is rare to use units of amount of substance other than the mole, the Avogadro constant can be expressed by pound-mole and ounce-mole. The current definition of the mole links it to the kilogram; the revised definition breaks that link by making a mole a specific number of entities of the substance in question. Previous definition: The mole is the amount of substance of a system that contains as many elementary entities as there are atoms in 0.012 kilogram of carbon-12. When the mole is used, the elementary entities must be specified and may be atoms, ions, other particles, or specified groups of such particles. 2019 definition: The mole, symbol mol, is the SI unit of amount of substance. One mole contains 6.02214076×1023 elementary entities. This number is the fixed numerical value of the Avogadro constant, NA, when expressed in the unit mol−1 and is called the Avogadro number; the am
National Institute of Standards and Technology
The National Institute of Standards and Technology is a physical sciences laboratory, a non-regulatory agency of the United States Department of Commerce. Its mission is to promote industrial competitiveness. NIST's activities are organized into laboratory programs that include nanoscale science and technology, information technology, neutron research, material measurement, physical measurement; the American AI initiative has called NIST to lead the development of appropriate technical standards for reliable, trustworthy, secure and interoperable AI systems. The Articles of Confederation, ratified by the colonies in 1781, contained the clause, "The United States in Congress assembled shall have the sole and exclusive right and power of regulating the alloy and value of coin struck by their own authority, or by that of the respective states—fixing the standards of weights and measures throughout the United States". Article 1, section 8, of the Constitution of the United States, transferred this power to Congress.
To coin money, regulate the value thereof, of foreign coin, fix the standard of weights and measures". In January 1790, President George Washington, in his first annual message to Congress stated that, "Uniformity in the currency and measures of the United States is an object of great importance, will, I am persuaded, be duly attended to", ordered Secretary of State Thomas Jefferson to prepare a plan for Establishing Uniformity in the Coinage and Measures of the United States, afterwards referred to as the Jefferson report. On October 25, 1791, Washington appealed a third time to Congress, "A uniformity of the weights and measures of the country is among the important objects submitted to you by the Constitution and if it can be derived from a standard at once invariable and universal, must be no less honorable to the public council than conducive to the public convenience", but it was not until 1838, that a uniform set of standards was worked out. In 1821, John Quincy Adams had declared "Weights and measures may be ranked among the necessities of life to every individual of human society".
From 1830 until 1901, the role of overseeing weights and measures was carried out by the Office of Standard Weights and Measures, part of the United States Department of the Treasury. In 1901, in response to a bill proposed by Congressman James H. Southard, the National Bureau of Standards was founded with the mandate to provide standard weights and measures, to serve as the national physical laboratory for the United States. President Theodore Roosevelt appointed Samuel W. Stratton as the first director; the budget for the first year of operation was $40,000. The Bureau took custody of the copies of the kilogram and meter bars that were the standards for US measures, set up a program to provide metrology services for United States scientific and commercial users. A laboratory site was constructed in Washington, DC, instruments were acquired from the national physical laboratories of Europe. In addition to weights and measures, the Bureau developed instruments for electrical units and for measurement of light.
In 1905 a meeting was called that would be the first "National Conference on Weights and Measures". Conceived as purely a metrology agency, the Bureau of Standards was directed by Herbert Hoover to set up divisions to develop commercial standards for materials and products.page 133 Some of these standards were for products intended for government use, but product standards affected private-sector consumption. Quality standards were developed for products including some types of clothing, automobile brake systems and headlamps and electrical safety. During World War I, the Bureau worked on multiple problems related to war production operating its own facility to produce optical glass when European supplies were cut off. Between the wars, Harry Diamond of the Bureau developed a blind approach radio aircraft landing system. During World War II, military research and development was carried out, including development of radio propagation forecast methods, the proximity fuze and the standardized airframe used for Project Pigeon, shortly afterwards the autonomously radar-guided Bat anti-ship guided bomb and the Kingfisher family of torpedo-carrying missiles.
In 1948, financed by the United States Air Force, the Bureau began design and construction of SEAC, the Standards Eastern Automatic Computer. The computer went into operation in May 1950 using a combination of vacuum tubes and solid-state diode logic. About the same time the Standards Western Automatic Computer, was built at the Los Angeles office of the NBS by Harry Huskey and used for research there. A mobile version, DYSEAC, was built for the Signal Corps in 1954. Due to a changing mission, the "National Bureau of Standards" became the "National Institute of Standards and Technology" in 1988. Following September 11, 2001, NIST conducted the official investigation into the collapse of the World Trade Center buildings. NIST, known between 1901 and 1988 as the National Bureau of Standards, is a measurement standards laboratory known as a National Metrological Institute, a non-regulatory agency of the United States Department of Commerce; the institute's official mission is to: Promote U. S. innovation and industrial competitiveness by advancing measurement science and technology in ways that enhance economic security and improve our quality of life.
NIST had an operating budget for fiscal year 2007 of about $843.3 million. NIST's 2009 budget was $992 million
ArXiv is a repository of electronic preprints approved for posting after moderation, but not full peer review. It consists of scientific papers in the fields of mathematics, astronomy, electrical engineering, computer science, quantitative biology, mathematical finance and economics, which can be accessed online. In many fields of mathematics and physics all scientific papers are self-archived on the arXiv repository. Begun on August 14, 1991, arXiv.org passed the half-million-article milestone on October 3, 2008, had hit a million by the end of 2014. By October 2016 the submission rate had grown to more than 10,000 per month. ArXiv was made possible by the compact TeX file format, which allowed scientific papers to be transmitted over the Internet and rendered client-side. Around 1990, Joanne Cohn began emailing physics preprints to colleagues as TeX files, but the number of papers being sent soon filled mailboxes to capacity. Paul Ginsparg recognized the need for central storage, in August 1991 he created a central repository mailbox stored at the Los Alamos National Laboratory which could be accessed from any computer.
Additional modes of access were soon added: FTP in 1991, Gopher in 1992, the World Wide Web in 1993. The term e-print was adopted to describe the articles, it began as a physics archive, called the LANL preprint archive, but soon expanded to include astronomy, computer science, quantitative biology and, most statistics. Its original domain name was xxx.lanl.gov. Due to LANL's lack of interest in the expanding technology, in 2001 Ginsparg changed institutions to Cornell University and changed the name of the repository to arXiv.org. It is now hosted principally with eight mirrors around the world, its existence was one of the precipitating factors that led to the current movement in scientific publishing known as open access. Mathematicians and scientists upload their papers to arXiv.org for worldwide access and sometimes for reviews before they are published in peer-reviewed journals. Ginsparg was awarded a MacArthur Fellowship in 2002 for his establishment of arXiv; the annual budget for arXiv is $826,000 for 2013 to 2017, funded jointly by Cornell University Library, the Simons Foundation and annual fee income from member institutions.
This model arose in 2010, when Cornell sought to broaden the financial funding of the project by asking institutions to make annual voluntary contributions based on the amount of download usage by each institution. Each member institution pledges a five-year funding commitment to support arXiv. Based on institutional usage ranking, the annual fees are set in four tiers from $1,000 to $4,400. Cornell's goal is to raise at least $504,000 per year through membership fees generated by 220 institutions. In September 2011, Cornell University Library took overall administrative and financial responsibility for arXiv's operation and development. Ginsparg was quoted in the Chronicle of Higher Education as saying it "was supposed to be a three-hour tour, not a life sentence". However, Ginsparg remains on the arXiv Scientific Advisory Board and on the arXiv Physics Advisory Committee. Although arXiv is not peer reviewed, a collection of moderators for each area review the submissions; the lists of moderators for many sections of arXiv are publicly available, but moderators for most of the physics sections remain unlisted.
Additionally, an "endorsement" system was introduced in 2004 as part of an effort to ensure content is relevant and of interest to current research in the specified disciplines. Under the system, for categories that use it, an author must be endorsed by an established arXiv author before being allowed to submit papers to those categories. Endorsers are not asked to review the paper for errors, but to check whether the paper is appropriate for the intended subject area. New authors from recognized academic institutions receive automatic endorsement, which in practice means that they do not need to deal with the endorsement system at all. However, the endorsement system has attracted criticism for restricting scientific inquiry. A majority of the e-prints are submitted to journals for publication, but some work, including some influential papers, remain purely as e-prints and are never published in a peer-reviewed journal. A well-known example of the latter is an outline of a proof of Thurston's geometrization conjecture, including the Poincaré conjecture as a particular case, uploaded by Grigori Perelman in November 2002.
Perelman appears content to forgo the traditional peer-reviewed journal process, stating: "If anybody is interested in my way of solving the problem, it's all there – let them go and read about it". Despite this non-traditional method of publication, other mathematicians recognized this work by offering the Fields Medal and Clay Mathematics Millennium Prizes to Perelman, both of which he refused. Papers can be submitted in any of several formats, including LaTeX, PDF printed from a word processor other than TeX or LaTeX; the submission is rejected by the arXiv software if generating the final PDF file fails, if any image file is too large, or if the total size of the submission is too large. ArXiv now allows one to store and modify an incomplete submission, only finalize the submission when ready; the time stamp on the article is set. The standard access route is through one of several mirrors. Sev
2019 redefinition of SI base units
A redefinition of SI base units is scheduled to come into force on 20 May 2019. The kilogram, ampere and mole will be defined by setting exact numerical values for the Planck constant, the elementary electric charge, the Boltzmann constant, the Avogadro constant, respectively; the metre and candela are defined by physical constants, subject to correction to their present definitions. The new definitions aim to improve the SI without changing the size of any units, thus ensuring continuity with existing measurements. In November 2018, the 26th General Conference on Weights and Measures unanimously approved these changes, which the International Committee for Weights and Measures had proposed earlier that year.:23The previous major change of the metric system was in 1960 when the International System of Units was formally published. At this time the metre was redefined, from being defined in terms of the prototype metre, to being defined in terms of the wavelength of a spectral line of a krypton-86 radiation, making it derivable from universal natural phenomena.
The kilogram remained defined in terms of a physical prototype, leaving it the only artefact upon which the SI unit definitions depend. At this time the SI, as a coherent system, was constructed around seven base units, powers of which were used to construct all other units. With the 2019 redefinition, the SI is instead constructed around seven defining constants, allowing all units to be constructed directly from these constants, with the designation of base units being retained although no longer essential; the metric system was conceived as a system of measurement, derivable from unchanging phenomena, but practical limitations necessitated the use of artefacts when the metric system was first introduced in France in 1799. Although designed for long-term stability, the masses of the kilogram prototype and its secondary copies have shown small variations over time relative to each other, they are not thought to be adequate for the increasing accuracy demanded by science, prompting a search for a suitable replacement.
Some units were defined based on measurements that are difficult to realise in a laboratory, such as the definition of the kelvin in terms of the triple point of water. With the 2019 redefinition, the SI is for the first time wholly derivable from natural phenomena, with most units based on fundamental physical constants. A number of authors have published criticisms of the revised definitions – including that the proposal had failed to address the impact of breaking the link between the definition of the dalton and the definitions of the kilogram, the mole, the Avogadro constant; the basic structure of SI was developed over a period of about 170 years. Since 1960, technological advances have made it possible to address various weaknesses in SI, such as the dependence on an artefact to define the kilogram. During the early years of the French Revolution, the leaders of the French National Constituent Assembly decided to introduce a new system of measurement based on the principles of logic and natural phenomena.
The metre was defined as one ten-millionth of the distance from the North Pole to the Equator, the kilogram as the mass of one thousandth of a cubic metre of pure water. Although these definitions were chosen so that nobody would "own" the units, they could not be measured with sufficient convenience or precision for practical use. Instead, realisations were created in the form of the mètre des Archives and kilogramme des Archives which were a "best attempt" at fulfilling these principles. In 1875, by which time the use of the metric system had become widespread in Europe and in Latin America, twenty industrially developed nations met for the Convention of the Metre; the result was the signing of the Treaty of the Metre under which three bodies were set up to take custody of the international prototype kilogram and metre and to regulate comparisons with national prototypes. They were: CGPM – The Conference meets every four to six years and consists of delegates of the nations who had signed the convention.
It discusses and examines the arrangements required to ensure the propagation and improvement of the International System of Units and it endorses the results of new fundamental metrological determinations. CIPM – The Committee consists of eighteen eminent scientists, each from a different country, nominated by the CGPM; the CIPM meets annually and is tasked to advise the CGPM. The CIPM has set up a number of sub-committees, each charged with a particular area of interest. One of these, the Consultative Committee for Units, amongst other things, advises the CIPM on matters concerning units of measurement. BIPM – The Bureau provides safe keeping of the international prototype kilogram and metre, provides laboratory facilities for regular comparisons of the national prototypes with the international prototype and is the secretariat for the CIPM and the CGPM; the first CGPM formally approved the use of 40 prototype metres and 40 prototype kilograms from the British firm Johnson Matthey as the standards mandated by the Convention of the Metre.
One of each of these was nominated by lot as the international prototypes, other copies were retained by the CGPM as working copies, the rest were distributed to member nations for use as their national prototypes. At regular intervals the national prototypes were compared with and recalibrated
Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe. The earliest roots of science can be traced to Ancient Egypt and Mesopotamia in around 3500 to 3000 BCE, their contributions to mathematics and medicine entered and shaped Greek natural philosophy of classical antiquity, whereby formal attempts were made to explain events of the physical world based on natural causes. After the fall of the Western Roman Empire, knowledge of Greek conceptions of the world deteriorated in Western Europe during the early centuries of the Middle Ages but was preserved in the Muslim world during the Islamic Golden Age; the recovery and assimilation of Greek works and Islamic inquiries into Western Europe from the 10th to 13th century revived natural philosophy, transformed by the Scientific Revolution that began in the 16th century as new ideas and discoveries departed from previous Greek conceptions and traditions. The scientific method soon played a greater role in knowledge creation and it was not until the 19th century that many of the institutional and professional features of science began to take shape.
Modern science is divided into three major branches that consist of the natural sciences, which study nature in the broadest sense. There is disagreement, however, on whether the formal sciences constitute a science as they do not rely on empirical evidence. Disciplines that use existing scientific knowledge for practical purposes, such as engineering and medicine, are described as applied sciences. Science is based on research, conducted in academic and research institutions as well as in government agencies and companies; the practical impact of scientific research has led to the emergence of science policies that seek to influence the scientific enterprise by prioritizing the development of commercial products, health care, environmental protection. Science in a broad sense existed in many historical civilizations. Modern science is distinct in its approach and successful in its results, so it now defines what science is in the strictest sense of the term. Science in its original sense was a word for a type of knowledge, rather than a specialized word for the pursuit of such knowledge.
In particular, it was the type of knowledge which people can communicate to share. For example, knowledge about the working of natural things was gathered long before recorded history and led to the development of complex abstract thought; this is shown by the construction of complex calendars, techniques for making poisonous plants edible, public works at national scale, such as those which harnessed the floodplain of the Yangtse with reservoirs and dikes, buildings such as the Pyramids. However, no consistent conscious distinction was made between knowledge of such things, which are true in every community, other types of communal knowledge, such as mythologies and legal systems. Metallurgy was known in prehistory, the Vinča culture was the earliest known producer of bronze-like alloys, it is thought that early experimentation with heating and mixing of substances over time developed into alchemy. Neither the words nor the concepts "science" and "nature" were part of the conceptual landscape in the ancient near east.
The ancient Mesopotamians used knowledge about the properties of various natural chemicals for manufacturing pottery, glass, metals, lime plaster, waterproofing. The Mesopotamians had intense interest in medicine and the earliest medical prescriptions appear in Sumerian during the Third Dynasty of Ur. Nonetheless, the Mesopotamians seem to have had little interest in gathering information about the natural world for the mere sake of gathering information and only studied scientific subjects which had obvious practical applications or immediate relevance to their religious system. In the classical world, there is no real ancient analog of a modern scientist. Instead, well-educated upper-class, universally male individuals performed various investigations into nature whenever they could afford the time. Before the invention or discovery of the concept of "nature" by the Pre-Socratic philosophers, the same words tend to be used to describe the natural "way" in which a plant grows, the "way" in which, for example, one tribe worships a particular god.
For this reason, it is claimed these men were the first philosophers in the strict sense, the first people to distinguish "nature" and "convention." Natural philosophy, the precursor of natural science, was thereby distinguished as the knowledge of nature and things which are true for every community, the name of the specialized pursuit of such knowledge was philosophy – the realm of the first philosopher-physicists. They were speculators or theorists interested in astronomy. In contrast, trying to use knowledge of nature to imitate nature was seen by classical scientists as a more appropriate interest for lower class artisans; the early Greek philosophers of the Milesian school, founded by Thales of Miletus and continued by his successors A
Technology is the collection of techniques, skills and processes used in the production of goods or services or in the accomplishment of objectives, such as scientific investigation. Technology can be the knowledge of techniques and the like, or it can be embedded in machines to allow for operation without detailed knowledge of their workings. Systems applying technology by taking an input, changing it according to the system's use, producing an outcome are referred to as technology systems or technological systems; the simplest form of technology is the use of basic tools. The prehistoric discovery of how to control fire and the Neolithic Revolution increased the available sources of food, the invention of the wheel helped humans to travel in and control their environment. Developments in historic times, including the printing press, the telephone, the Internet, have lessened physical barriers to communication and allowed humans to interact on a global scale. Technology has many effects, it has allowed the rise of a leisure class.
Many technological processes produce unwanted by-products known as pollution and deplete natural resources to the detriment of Earth's environment. Innovations have always influenced the values of a society and raised new questions in the ethics of technology. Examples include the rise of the notion of efficiency in terms of human productivity, the challenges of bioethics. Philosophical debates have arisen over the use of technology, with disagreements over whether technology improves the human condition or worsens it. Neo-Luddism, anarcho-primitivism, similar reactionary movements criticize the pervasiveness of technology, arguing that it harms the environment and alienates people; the use of the term "technology" has changed over the last 200 years. Before the 20th century, the term was uncommon in English, it was used either to refer to the description or study of the useful arts or to allude to technical education, as in the Massachusetts Institute of Technology; the term "technology" rose to prominence in the 20th century in connection with the Second Industrial Revolution.
The term's meanings changed in the early 20th century when American social scientists, beginning with Thorstein Veblen, translated ideas from the German concept of Technik into "technology." In German and other European languages, a distinction exists between technik and technologie, absent in English, which translates both terms as "technology." By the 1930s, "technology" referred not only to the study of the industrial arts but to the industrial arts themselves. In 1937, the American sociologist Read Bain wrote that "technology includes all tools, utensils, instruments, clothing and transporting devices and the skills by which we produce and use them." Bain's definition remains common among scholars today social scientists. Scientists and engineers prefer to define technology as applied science, rather than as the things that people make and use. More scholars have borrowed from European philosophers of "technique" to extend the meaning of technology to various forms of instrumental reason, as in Foucault's work on technologies of the self.
Dictionaries and scholars have offered a variety of definitions. The Merriam-Webster Learner's Dictionary offers a definition of the term: "the use of science in industry, etc. to invent useful things or to solve problems" and "a machine, piece of equipment, etc., created by technology." Ursula Franklin, in her 1989 "Real World of Technology" lecture, gave another definition of the concept. The term is used to imply a specific field of technology, or to refer to high technology or just consumer electronics, rather than technology as a whole. Bernard Stiegler, in Technics and Time, 1, defines technology in two ways: as "the pursuit of life by means other than life," and as "organized inorganic matter."Technology can be most broadly defined as the entities, both material and immaterial, created by the application of mental and physical effort in order to achieve some value. In this usage, technology refers to tools and machines that may be used to solve real-world problems, it is a far-reaching term that may include simple tools, such as a crowbar or wooden spoon, or more complex machines, such as a space station or particle accelerator.
Tools and machines need not be material. W. Brian Arthur defines technology in a broad way as "a means to fulfill a human purpose."The word "technology" can be used to refer to a collection of techniques. In this context, it is the current state of humanity's knowledge of how to combine resources to produce desired products, to solve problems, fulfill needs, or satisfy wants; when combined with another term, such as "medical technology" or "space technology," it refers to the state of the respective field's knowledge and tools. "State-of-the-art technology" refers to the high technology available to humanity in any field. Technology can be viewed as an activity that changes culture. Additionally, technology is the application of math, science, an