Marie Skłodowska Curie, born Maria Salomea Skłodowska, was a Polish and naturalized-French physicist and chemist who conducted pioneering research on radioactivity. She was the first woman to become a professor at the University of Paris and she was born in Warsaw, in what was the Kingdom of Poland, part of the Russian Empire. She studied at Warsaws clandestine Floating University and began her scientific training in Warsaw. In 1891, aged 24, she followed her older sister Bronisława to study in Paris and she shared the 1903 Nobel Prize in Physics with her husband Pierre Curie and with physicist Henri Becquerel. She won the 1911 Nobel Prize in Chemistry and her achievements included the development of the theory of radioactivity, techniques for isolating radioactive isotopes, and the discovery of two elements and radium. Under her direction, the worlds first studies were conducted into the treatment of neoplasms and she founded the Curie Institutes in Paris and in Warsaw, which remain major centres of medical research today.
During World War I, she developed mobile radiography units to provide X-ray services to field hospitals, while a French citizen, Marie Skłodowska Curie never lost her sense of Polish identity. She taught her daughters the Polish language and took them on visits to Poland and she named the first chemical element that she discovered—polonium, which she isolated in 1898—after her native country. Maria Skłodowska was born in Warsaw, in the Russian partition of Poland, on 7 November 1867, the fifth and youngest child of well-known teachers Bronisława, née Boguska, the elder siblings of Maria were Zofia, Józef, Bronisława and Helena. On both the paternal and maternal sides, the family had lost their property and fortunes through patriotic involvements in Polish national uprisings aimed at restoring Polands independence. This condemned the subsequent generation, including Maria, her sisters and her brother. Marias paternal grandfather, Józef Skłodowski, had been a teacher in Lublin, where he taught the young Bolesław Prus.
Her father, Władysław Skłodowski, taught mathematics and physics, subjects that Maria was to pursue, after Russian authorities eliminated laboratory instruction from the Polish schools, he brought much of the laboratory equipment home, and instructed his children in its use. Marias mother Bronisława operated a prestigious Warsaw boarding school for girls and she died of tuberculosis in May 1878, when Maria was ten years old. Less than three years earlier, Marias oldest sibling, had died of typhus contracted from a boarder, Marias father was an atheist, her mother a devout Catholic. The deaths of Marias mother and sister caused her to give up Catholicism and become agnostic. When she was ten years old, Maria began attending the school of J. Sikorska, next she attended a gymnasium for girls. After a collapse, possibly due to depression, she spent the year in the countryside with relatives of her father, and the next year with her father in Warsaw
National Academy of Sciences
The National Academy of Sciences is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences and Medicine, along with the National Academy of Engineering, as a national academy, new members of the organization are elected annually by current members, based on their distinguished and continuing achievements in original research. Election to the National Academies is one of the highest honors in the scientific field, members serve pro bono as advisers to the nation on science and medicine. The group holds a congressional charter under Title 36 of the United States Code, … to provide scientific advice to the government whenever called upon by any government department. The Academy receives no compensation from the government for its services, as of 2016, the National Academy of Sciences includes about 2,350 members and 450 foreign associates. It employed about 1,100 staff in 2005, the current members annually elect new members for life. Approximately 200 members have won a Nobel Prize, the National Academy of Sciences is a member of the International Council for Science.
Although there is no relationship with state and local academies of science. The National Academies is governed by a 17-member Council, made up of five officers and 12 Councilors, the National Academy of Sciences meets annually in Washington, D. C. which is documented in the Proceedings of the National Academy of Sciences, its scholarly journal. The National Academies Press is the publisher for the National Academies, since 2004, the National Academy of Sciences has administered the Marian Koshland Science Museum to provide public exhibits and programming related to its policy work. The museums current exhibits focus on change and infectious disease. The National Academy of Sciences maintains multiple buildings around the United States, the building has a neoclassical architectural style and was built by architect Bertram Grosvenor Goodhue. The building was dedicated in 1924 and is listed on the National Register of Historic Places, the building is used for lectures, symposia and concerts, in addition to annual meetings of the NAS, NAE, and NAM.
The 2012 Presidential Award for Math and Science Teaching ceremony was held here on March 5,2014, approximately 150 staff members work at the NAS Building. More than 1,000 National Academies staff members work at The Keck Center of the National Academies at 500 Fifth Street in northwest Washington, the Keck Center provides meeting space and houses the National Academies Press Bookstore. The NAS maintains conference centers in California and Massachusetts, the J. Erik Jonsson Conference Center located at 314 Quissett Avenue in Woods Hole, Massachusetts, is another conference facility. The Act of Incorporation, signed by President Abraham Lincoln on March 3,1863, created the National Academy of Sciences, many of the original NAS members came from the so-called Scientific Lazzaroni, an informal network of mostly physical scientists working in the vicinity of Cambridge, Massachusetts. Senator Henry Wilson of Massachusetts was to name Agassiz to the Board of Regents of the Smithsonian Institution, Agassiz was to come to Washington at the governments expense to plan the organization with the others
Chemistry is a branch of physical science that studies the composition, structure and change of matter. Chemistry is sometimes called the science because it bridges other natural sciences, including physics. For the differences between chemistry and physics see comparison of chemistry and physics, the history of chemistry can be traced to alchemy, which had been practiced for several millennia in various parts of the world. The word chemistry comes from alchemy, which referred to a set of practices that encompassed elements of chemistry, philosophy, astronomy, mysticism. An alchemist was called a chemist in popular speech, and the suffix -ry was added to this to describe the art of the chemist as chemistry, the modern word alchemy in turn is derived from the Arabic word al-kīmīā. In origin, the term is borrowed from the Greek χημία or χημεία and this may have Egyptian origins since al-kīmīā is derived from the Greek χημία, which is in turn derived from the word Chemi or Kimi, which is the ancient name of Egypt in Egyptian.
Alternately, al-kīmīā may derive from χημεία, meaning cast together, in retrospect, the definition of chemistry has changed over time, as new discoveries and theories add to the functionality of the science. The term chymistry, in the view of noted scientist Robert Boyle in 1661, in 1837, Jean-Baptiste Dumas considered the word chemistry to refer to the science concerned with the laws and effects of molecular forces. More recently, in 1998, Professor Raymond Chang broadened the definition of chemistry to mean the study of matter, early civilizations, such as the Egyptians Babylonians, Indians amassed practical knowledge concerning the arts of metallurgy and dyes, but didnt develop a systematic theory. Greek atomism dates back to 440 BC, arising in works by such as Democritus and Epicurus. In 50 BC, the Roman philosopher Lucretius expanded upon the theory in his book De rerum natura, unlike modern concepts of science, Greek atomism was purely philosophical in nature, with little concern for empirical observations and no concern for chemical experiments.
Work, particularly the development of distillation, continued in the early Byzantine period with the most famous practitioner being the 4th century Greek-Egyptian Zosimos of Panopolis. He formulated Boyles law, rejected the four elements and proposed a mechanistic alternative of atoms. Before his work, many important discoveries had been made, the Scottish chemist Joseph Black and the Dutchman J. B. English scientist John Dalton proposed the theory of atoms, that all substances are composed of indivisible atoms of matter. Davy discovered nine new elements including the alkali metals by extracting them from their oxides with electric current, british William Prout first proposed ordering all the elements by their atomic weight as all atoms had a weight that was an exact multiple of the atomic weight of hydrogen. The inert gases, called the noble gases were discovered by William Ramsay in collaboration with Lord Rayleigh at the end of the century, thereby filling in the basic structure of the table.
Organic chemistry was developed by Justus von Liebig and others, following Friedrich Wöhlers synthesis of urea which proved that organisms were, in theory
ETH Zurich is a science, technology and mathematics university in the city of Zürich, Switzerland. ETH Zurich is consistently ranked among the top universities in the world, twenty-one Nobel Prizes have been awarded to students or professors of the Institute in the past, the most famous of whom was Albert Einstein. It is a member of the IDEA League and the International Alliance of Research Universities. ETH was founded in 1854 by the Swiss Confederation and began giving its first lectures in 1855 as a polytechnic institute and it is locally still known as Poly, derived from the original name Eidgenössische polytechnische Schule, which translates to Federal Polytechnic School. ETH is an institute, whereas the University of Zürich is a cantonal institution. In the beginning, both universities were co-located in the buildings of the University of Zürich, from 1905 to 1908, under the presidency of Jérôme Franel, the course program of ETH was restructured to that of a real university and ETH was granted the right to award doctorates.
In 1909 the first doctorates were awarded, in 1911, it was given its current name, Eidgenössische Technische Hochschule. In 1924, another reorganization structured the university in 12 departments, however, it now has 16 departments. ETH Zurich, the EPFL, and four associated research institutes form the ETH Domain with the aim of collaborating on scientific projects, ETH Zurich is ranked among the top universities in the world. Historically, ETH Zurich has achieved its reputation particularly in the fields of chemistry, there are 21 Nobel Laureates who are associated with ETH. The most recent Nobel Laureate is Richard F, heck who was awarded the Nobel Prize in chemistry in 2010. Albert Einstein is perhaps its most famous alumnus, in 2016, the QS World University Rankings placed ETH Zurich at 8th overall in the world. In 2015, ETH ranked 6th in the world in Natural Sciences, ETH Zurich had an budget of 1.712 billion CHF in the year 2015 to support its cutting-edge research. For Swiss students, ETH is not selective in its admission procedures.
Like every public university in Switzerland, ETH is obliged to grant admission to every Swiss resident who took the Matura, an applicant can be admitted to ETH even without any verifiable educational records by passing the comprehensive entrance exam. As at all universities in Switzerland, the year is divided into two semesters. Examinations are often held during examination sessions which are immediately before the beginning of the next semester, after the first year of study, bachelor students must pass a block examination of all courses taken in the first year, called the Basisprüfung. If the weighted average score is not sufficient, a student is required to retake the entire Basisprüfung which usually means having to re-sit the whole first year
A ceramic is an inorganic, non-metallic, solid material comprising metal, non-metal or metalloid atoms primarily held in ionic and covalent bonds. This article gives an overview of ceramic materials from the point of view of materials science, the crystallinity of ceramic materials ranges from highly oriented to semi-crystalline and often completely amorphous. Most often, fired ceramics are either vitrified or semi-vitrified as is the case with earthenware, varying crystallinity and electron consumption in the ionic and covalent bonds cause most ceramic materials to be good thermal and electrical insulators. With such a range of possible options for the composition/structure of a ceramic, the breadth of the subject is vast. Many composites, such as fiberglass and carbon fiber, while containing ceramic materials, are not considered to be part of the ceramic family. The earliest ceramics made by humans were pottery objects or figurines made from clay, either by itself or mixed with materials like silica, sintered.
Later ceramics were glazed and fired to create smooth, colored surfaces, decreasing porosity through the use of glassy, ceramics now include domestic and building products, as well as a wide range of ceramic art. In the 20th century, new materials were developed for use in advanced ceramic engineering. The word ceramic comes from the Greek word κεραμικός, of pottery or for pottery, from κέραμος, potters clay, the earliest known mention of the root ceram- is the Mycenaean Greek ke-ra-me-we, workers of ceramics, written in Linear B syllabic script. The word ceramic may be used as an adjective to describe a material, product or process, or it may be used as a noun, either singular, or, more commonly, as the plural noun ceramics. A ceramic material is an inorganic, non-metallic, often crystalline oxide, nitride or carbide material, some elements, such as carbon or silicon, may be considered ceramics. Ceramic materials are brittle, strong in compression, weak in shearing and they withstand chemical erosion that occurs in other materials subjected to acidic or caustic environments.
Ceramics generally can withstand high temperatures, such as temperatures that range from 1,000 °C to 1,600 °C. Glass is often not considered a ceramic because of its amorphous character. However, glassmaking involves several steps of the process and its mechanical properties are similar to ceramic materials. Traditional ceramic raw materials include minerals such as kaolinite, whereas more recent materials include aluminium oxide. The modern ceramic materials, which are classified as advanced ceramics, include silicon carbide, both are valued for their abrasion resistance, and hence find use in applications such as the wear plates of crushing equipment in mining operations. Advanced ceramics are used in the medicine, electronics industries. Crystalline ceramic materials are not amenable to a range of processing
High-temperature superconductors are materials that behave as superconductors at unusually high temperatures. Several iron-based compounds are now known to be superconducting at high temperatures, in 2015, hydrogen sulfide under extremely high pressure was found to undergo superconducting transition near 203 K, the highest temperature superconductor known to date. For an explanation about Tc, see Superconductivity § Superconducting phase transition, the phenomenon of superconductivity was discovered by Kamerlingh Onnes in 1911, in metallic mercury below 4 K. Ever since, researchers have attempted to observe superconductivity at increasing temperatures with the goal of finding a room-temperature superconductor, in the late 1970s, superconductivity was observed in certain metal oxides at temperatures as high as 13 K, which were much higher than those for elemental metals. In 1986, J. Georg Bednorz and K. Alex Müller, working at the IBM research lab near Zurich, Bednorz encountered a barium-doped compound of lanthanum and copper oxide whose resistance dropped down to zero at a temperature around 35 K.
Their results were confirmed by many groups, notably Paul Chu at the University of Houston. These superconductors are now known to possess a d-wave pair symmetry, until 2015 the superconductor with the highest transition temperature that had been confirmed by multiple independent research groups was mercury barium calcium copper oxide at around 133 K. One of the properties of the structure of oxide superconductors is an alternating multi-layer of CuO2 planes with superconductivity taking place between these layers. The more layers of CuO2, the higher Tc and this structure causes a large anisotropy in normal conducting and superconducting properties, since electrical currents are carried by holes induced in the oxygen sites of the CuO2 sheets. The electrical conduction is highly anisotropic, with a higher conductivity parallel to the CuO2 plane than in the perpendicular direction. Generally, critical temperatures depend on the compositions, cations substitutions. Thus, this particular superconductor is often referred to as the 123 superconductor, the unit cell of YBa2Cu3O7 consists of three pseudocubic elementary perovskite unit cells.
Each perovskite unit cell contains a Y or Ba atom at the center, Ba in the unit cell, Y in the middle one. Thus, Y and Ba are stacked in the sequence along the c-axis, all corner sites of the unit cell are occupied by Cu, which has two different coordinations, Cu and Cu, with respect to oxygen. There are four possible sites for oxygen, O, O, O and O. The coordination polyhedra of Y and Ba with respect to oxygen are different, the tripling of the perovskite unit cell leads to nine oxygen atoms, whereas YBa2Cu3O7 has seven oxygen atoms and, therefore, is referred to as an oxygen-deficient perovskite structure. The structure has a stacking of different layers, one of the key feature of the unit cell of YBa2Cu3O7−x is the presence of two layers of CuO2. The role of the Y plane is to serve as a spacer between two CuO2 planes, in YBCO, the Cu–O chains are known to play an important role for superconductivity
Gabriel Lippmann was born in Bonnevoie, Luxembourg, on 16 August 1845. At the time, Bonnevoie was part of the commune of Hollerich which is given as his place of birth. His father, Isaïe, a French Jew born in Ennery near Metz, in 1848, the family moved to Paris where Lippmann was initially tutored by his mother, Miriam Rose, before attending the Lycée Napoléon. He was said to have been a rather inattentive but thoughtful pupil with a special interest in mathematics, Lippmann returned to Paris in 1875, where he continued to study until 1878, when he became professor of physics at the Sorbonne. Lippmann made several important contributions to various branches of physics over the years, in a paper delivered to the Philosophical Society of Glasgow on 17 January 1883, John G. The lower end is drawn into a point, until the diameter of the capillary is.005 of a millimetre. The tube is filled with mercury, and the point is immersed in dilute sulphuric acid. A platinum wire is put into connection with the mercury in each tube, such an instrument is very sensitive, and Lippmann states that it is possible to determine a difference of potential so small as that of one 10, 080th of a Daniell.
It is thus a very delicate means of observing and of measuring minute electromotive forces, Lippmanns PhD thesis, presented to the Sorbonne on 24 July 1875, was on electrocapillarity. In 1881, Lippmann predicted the converse piezoelectric effect, above all, Lippmann is remembered as the inventor of a method for reproducing colours by photography, based on the interference phenomenon, which earned him the Nobel Prize in Physics for 1908. In 1886, Lippmanns interest turned to a method of fixing the colours of the spectrum on a photographic plate. By April 1892, he was able to report that he had succeeded in producing colour images of a glass window, a group of flags, a bowl of oranges topped by a red poppy. He presented his theory of photography using the interference method in two papers to the Academy, one in 1894, the other in 1906. The interference phenomenon in optics occurs as a result of the propagation of light. In the case of ordinary incoherent light, the waves are distinct only within a microscopically thin volume of space next to the reflecting surface.
Lippmann made use of this phenomenon by projecting an image onto a photographic plate capable of recording detail smaller than the wavelengths of visible light. The light passed through the glass sheet into a very thin. After development, the result was a structure of laminae, distinct parallel layers composed of metallic silver grains
Hendrik Antoon Lorentz was a Dutch physicist who shared the 1902 Nobel Prize in Physics with Pieter Zeeman for the discovery and theoretical explanation of the Zeeman effect. He derived the equations which formed the basis of the special relativity theory of Albert Einstein. For this he received honours and distinctions during his life. Hendrik Lorentz was born in Arnhem, the son of Gerrit Frederik Lorentz, a well-off nurseryman, in 1862, after his mothers death, his father married Luberta Hupkes. Despite being raised as a Protestant, he was a freethinker in religious matters, from 1866 to 1869 he attended the Hogere Burger School in Arnhem, a new type of public high school recently established by Johan Rudolph Thorbecke. His results in school were exemplary, not only did he excel in the sciences and mathematics, but in English, French. In 1870 he passed the exams in languages which were required for admission to University. After earning a degree, he returned to Arnhem in 1871 to teach night school classes in mathematics.
On 17 November 1877, only 24 years of age, Hendrik Antoon Lorentz was appointed to the established chair in theoretical physics at the University of Leiden. The position had initially offered to Johan van der Waals. On 25 January 1878 Lorentz delivered his lecture on De moleculaire theoriën in de natuurkunde. In 1881 he became member of the Royal Netherlands Academy of Arts, during the first twenty years in Leiden, Lorentz was primarily interested in the theory of electromagnetism to explain the relationship of electricity and light. After that, he extended his research to a wider area while still focusing on theoretical physics. Lorentz made significant contributions to fields ranging from hydrodynamics to general relativity and his most important contributions were in the area of electromagnetism, the electron theory, and relativity. Lorentz theorized that atoms might consist of charged particles and suggested that the oscillations of charged particles were the source of light. When a colleague and former student of Lorentzs, Pieter Zeeman, discovered the Zeeman effect in 1896, the experimental and theoretical work was honored with the Nobel prize in physics in 1902.
Lorentz name is now associated with the Lorentz-Lorenz formula, the Lorentz force, the Lorentzian distribution, in 1892 and 1895 Lorentz worked on describing electromagnetic phenomena in reference frames that move relative to the luminiferous aether. He discovered that the transition from one to another reference frame could be simplified by using a new variable which he called local time
Max von Laue
Max Theodor Felix von Laue was a German physicist who won the Nobel Prize in Physics in 1914 for his discovery of the diffraction of X-rays by crystals. A strong objector to National Socialism, he was instrumental in re-establishing and organizing German science after World War II, Laue was born in Pfaffendorf, now part of Koblenz, to Julius Laue and Minna Zerrenner. At Göttingen, he was influenced by the physicists Woldemar Voigt and Max Abraham. After only one semester at Munich, he went to the Friedrich-Wilhelms-University of Berlin in 1902, there, he studied under Max Planck, who gave birth to the quantum theory revolution on 14 December 1900, when he delivered his famous paper before the Deutsche Physikalische Gesellschaft. Thereafter, Laue spent 1903 to 1905 at Göttingen, Laue completed his Habilitation in 1906 under Arnold Sommerfeld at LMU. In 1906, Laue became a Privatdozent in Berlin and an assistant to Planck and he met Albert Einstein for the first time, they became friends and Laue went on to contribute to the acceptance and development of Einstein’s theory of relativity.
Laue continued as assistant to Planck until 1909, in Berlin, he worked on the application of entropy to radiation fields and on the thermodynamic significance of the coherence of light waves. From 1909 to 1912, Laue was a Privatdozent at the Institute for Theoretical Physics, under Arnold Sommerfeld, during the 1911 Christmas recess and in January 1912, Paul Peter Ewald was finishing the writing of his doctoral thesis under Sommerfeld. It was on a walk through the Englischer Garten in Munich in January, the wavelengths of concern to Ewald were in the visible region of the spectrum and hence much larger than the spacing between the resonators in Ewald’s crystal model. Laue seemed distracted and wanted to know what would be the effect if much smaller wavelengths were considered, while at Munich, he wrote the first volume of his book on relativity during the period 1910 to 1911. In 1912, Laue was called to the University of Zurich as a professor of physics. In 1913, his father was raised to the ranks of hereditary nobility, in 1914 a new professor extraordinarius chair of theoretical physics had been created at the University of Berlin.
Laue was offered the position but turned it down, and it was offered to Max Born, but Born was in the army until WW I ended, and before he had occupied the chair, Laue changed his mind and accepted the position. From 1914 to 1919, Laue was at the University of Frankfurt as ordinarius professor of theoretical physics, from 1916, he was engaged in vacuum tube development, at the University of Würzburg, for use in military telephony and wireless communications. At the university in 1919, other notables were Walther Nernst, Fritz Haber, among Laue’s notable students at the university were Leó Szilárd, Fritz London, Max Kohler, and Erna Weber. In 1921, he published the volume of his book on relativity. As a consultant to the Physikalisch-Technische Reichsanstalt, Laue met Walther Meissner who was working there on superconductivity, Meissner had discovered that a weak magnetic field decays rapidly to zero in the interior of a superconductor, which is known as the Meissner effect. Laue showed in 1932 that the threshold of the magnetic field which destroys superconductivity varies with the shape of the body
Critical point (thermodynamics)
In thermodynamics, a critical point is the end point of a phase equilibrium curve. The most prominent example is the critical point, the end point of the pressure-temperature curve that designates conditions under which a liquid. At the critical point, defined by a critical temperature Tc, other examples include the liquid–liquid critical points in mixtures. For simplicity and clarity, the notion of critical point is best introduced by discussing a specific example. This was the first critical point to be discovered, and it is still the best known, the figure to the right shows the schematic PT diagram of a pure substance. The commonly known phases solid and vapor are separated by phase boundaries, at the triple point, all three phases can coexist. However, the liquid-vapor boundary terminates in an endpoint at some critical temperature Tc, in water, the critical point occurs at around 647 K and 22.064 MPa. In the vicinity of the point, the physical properties of the liquid. For instance, liquid water under normal conditions is nearly incompressible, has a low thermal expansion coefficient, has a dielectric constant.
At the critical point, only one phase exists, the heat of vaporization is zero. There is a point in the constant-temperature line on a PV diagram. This means that at the point, T = T =0 Above the critical point there exists a state of matter that is continuously connected with both the liquid and the gaseous state. The existence of a point was first discovered by Charles Cagniard de la Tour in 1822 and named by Dmitri Mendeleev in 1860. Cagniard showed that CO2 could be liquefied at 31 °C at a pressure of 73 atm, but not at a slightly higher temperature, even under pressures as high as 3,000 atm. Solving the above condition T =0 for the van der Waals equation, the van der Waals equation, based on a mean field theory, does not hold near the critical point. In particular, it predicts wrong scaling laws, the principle of corresponding states indicates that substances at equal reduced pressures and temperatures have equal reduced volumes. This relationship is true for many substances, but becomes increasingly inaccurate for large values of pr.
The liquid–liquid critical point of a solution, which occurs at the solution temperature
Germany, officially the Federal Republic of Germany, is a federal parliamentary republic in central-western Europe. It includes 16 constituent states, covers an area of 357,021 square kilometres, with about 82 million inhabitants, Germany is the most populous member state of the European Union. After the United States, it is the second most popular destination in the world. Germanys capital and largest metropolis is Berlin, while its largest conurbation is the Ruhr, other major cities include Hamburg, Cologne, Stuttgart, Düsseldorf and Leipzig. Various Germanic tribes have inhabited the northern parts of modern Germany since classical antiquity, a region named Germania was documented before 100 AD. During the Migration Period the Germanic tribes expanded southward, beginning in the 10th century, German territories formed a central part of the Holy Roman Empire. During the 16th century, northern German regions became the centre of the Protestant Reformation, in 1871, Germany became a nation state when most of the German states unified into the Prussian-dominated German Empire.
After World War I and the German Revolution of 1918–1919, the Empire was replaced by the parliamentary Weimar Republic, the establishment of the national socialist dictatorship in 1933 led to World War II and the Holocaust. After a period of Allied occupation, two German states were founded, the Federal Republic of Germany and the German Democratic Republic, in 1990, the country was reunified. In the 21st century, Germany is a power and has the worlds fourth-largest economy by nominal GDP. As a global leader in industrial and technological sectors, it is both the worlds third-largest exporter and importer of goods. Germany is a country with a very high standard of living sustained by a skilled. It upholds a social security and universal health system, environmental protection. Germany was a member of the European Economic Community in 1957. It is part of the Schengen Area, and became a co-founder of the Eurozone in 1999, Germany is a member of the United Nations, NATO, the G8, the G20, and the OECD.
The national military expenditure is the 9th highest in the world, the English word Germany derives from the Latin Germania, which came into use after Julius Caesar adopted it for the peoples east of the Rhine. This in turn descends from Proto-Germanic *þiudiskaz popular, derived from *þeudō, descended from Proto-Indo-European *tewtéh₂- people, the discovery of the Mauer 1 mandible shows that ancient humans were present in Germany at least 600,000 years ago. The oldest complete hunting weapons found anywhere in the world were discovered in a mine in Schöningen where three 380, 000-year-old wooden javelins were unearthed
Heike Kamerlingh Onnes
Heike Kamerlingh Onnes was a Dutch physicist and Nobel laureate. He exploited the Hampson-Linde cycle to investigate how materials behave when cooled to nearly absolute zero and his production of extreme cryogenic temperatures led to his discovery of superconductivity in 1911, for certain materials, electrical resistance abruptly vanishes at very low temperatures. Kamerlingh Onnes was born in Groningen and his father, Harm Kamerlingh Onnes, was a brickworks owner. His mother was Anna Gerdina Coers of Arnhem, in 1870, Kamerlingh Onnes attended the University of Groningen. He studied under Robert Bunsen and Gustav Kirchhoff at the University of Heidelberg from 1871 to 1873, again at Groningen, he obtained his masters in 1878 and a doctorate in 1879. His thesis was Nieuwe bewijzen voor de aswenteling der aarde, from 1878 to 1882 he was assistant to Johannes Bosscha, the director of the Delft Polytechnic, for whom he substituted as lecturer in 1881 and 1882. He was married to Maria Adriana Wilhelmina Elisabeth Bijleveld and had one child and his brother Menso Kamerlingh Onnes was a fairly well known painter, while his sister Jenny married another famous painter, Floris Verster.
From 1882 to 1923 Kamerlingh Onnes served as professor of physics at the University of Leiden. In 1904 he founded a very large cryogenics laboratory and invited other researchers to the location, the laboratory is known now as Kamerlingh Onnes Laboratory. Only one year after his appointment as professor he became member of the Royal Netherlands Academy of Arts, on 10 July 1908, he was the first to liquefy helium, using several precooling stages and the Hampson-Linde cycle based on the Joule-Thomson effect. This way he lowered the temperature to the point of helium. By reducing the pressure of the liquid helium he achieved a temperature near 1.5 K and these were the coldest temperatures achieved on earth at the time. The equipment employed is at the Boerhaave Museum in Leiden, in 1911 Kamerlingh Onnes measured the electrical conductivity of pure metals at very low temperatures. Others, including Kamerlingh Onnes, felt that an electrical resistance would steadily decrease. On 8 April 1911, Kamerlingh Onnes found that at 4.2 K the resistance in a solid mercury wire immersed in liquid helium suddenly vanished and he immediately realized the significance of the discovery.
He reported that Mercury has passed into a new state, which on account of its electrical properties may be called the superconductive state. He published more articles about the phenomenon, initially referring to it as supraconductivity and, some of the instruments he devised for his experiments can be seen at the Boerhaave Museum in Leiden. The apparatus he used to first liquefy helium is on display in the lobby of the department at Leiden University