1.
Physicist
–
A physicist is a scientist who has specialized knowledge in the field of physics, the exploration of the interactions of matter and energy across the physical universe. A physicist is a scientist who specializes or works in the field of physics, physicists generally are interested in the root or ultimate causes of phenomena, and usually frame their understanding in mathematical terms. Physicists can also apply their knowledge towards solving real-world problems or developing new technologies, some physicists specialize in sectors outside the science of physics itself, such as engineering. The study and practice of physics is based on a ladder of discoveries. Many mathematical and physical ideas used today found their earliest expression in ancient Greek culture and Asian culture, the bulk of physics education can be said to flow from the scientific revolution in Europe, starting with the work of Galileo and Kepler in the early 1600s. New knowledge in the early 21st century includes an increase in understanding physical cosmology. The term physicist was coined by William Whewell in his 1840 book The Philosophy of the Inductive Sciences, many physicist positions require an undergraduate degree in applied physics or a related science or a Masters degree like MSc, MPhil, MPhys or MSci. In a research oriented level, students tend to specialize in a particular field, Physics students also need training in mathematics, and also in computer science and programming. For being employed as a physicist a doctoral background may be required for certain positions, undergraduate students like BSc Mechanical Engineering, BSc Electrical and Computer Engineering, BSc Applied Physics. etc. With physics orientation are chosen as research assistants with faculty members, the highest honor awarded to physicists is the Nobel Prize in Physics, awarded since 1901 by the Royal Swedish Academy of Sciences. The three major employers of career physicists are academic institutions, laboratories, and private industries, with the largest employer being the last, physicists in academia or government labs tend to have titles such as Assistants, Professors, Sr. /Jr. As per the American Institute for Physics, some 20% of new physics Ph. D. s holds jobs in engineering development programs, while 14% turn to computer software, a majority of physicists employed apply their skills and training to interdisciplinary sectors. For industry or self-employment. and also in science and programming. Hence a majority of Physics bachelors degree holders are employed in the private sector, other fields are academia, government and military service, nonprofit entities, labs and teaching
Physicist
–
Albert Einstein, physicist who developed the theory of general relativity.
2.
Paris
–
Paris is the capital and most populous city of France. It has an area of 105 square kilometres and a population of 2,229,621 in 2013 within its administrative limits, the agglomeration has grown well beyond the citys administrative limits. By the 17th century, Paris was one of Europes major centres of finance, commerce, fashion, science, and the arts, and it retains that position still today. The aire urbaine de Paris, a measure of area, spans most of the Île-de-France region and has a population of 12,405,426. It is therefore the second largest metropolitan area in the European Union after London, the Metropole of Grand Paris was created in 2016, combining the commune and its nearest suburbs into a single area for economic and environmental co-operation. Grand Paris covers 814 square kilometres and has a population of 7 million persons, the Paris Region had a GDP of €624 billion in 2012, accounting for 30.0 percent of the GDP of France and ranking it as one of the wealthiest regions in Europe. The city is also a rail, highway, and air-transport hub served by two international airports, Paris-Charles de Gaulle and Paris-Orly. Opened in 1900, the subway system, the Paris Métro. It is the second busiest metro system in Europe after Moscow Metro, notably, Paris Gare du Nord is the busiest railway station in the world outside of Japan, with 262 millions passengers in 2015. In 2015, Paris received 22.2 million visitors, making it one of the top tourist destinations. The association 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 hosted the 1900 and 1924 Summer Olympics and is bidding to host the 2024 Summer Olympics. The name Paris is derived from its inhabitants, the Celtic Parisii tribe. Thus, though written the same, the name is not related to the Paris of Greek mythology. In the 1860s, the boulevards and streets of Paris were illuminated by 56,000 gas lamps, since the late 19th century, Paris has also been known as Panam in French slang. Inhabitants are known in English as Parisians and in French as Parisiens and they are also 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 areas major north-south trade routes crossed the Seine on the île de la Cité, this place of land and water trade routes gradually became a town
Paris
–
In the 1860s Paris streets and monuments were illuminated by 56,000 gas lamps, making it literally "The City of Light."
Paris
Paris
–
Gold coins minted by the Parisii (1st century BC)
Paris
–
The
Palais de la Cité and
Sainte-Chapelle, viewed from the Left Bank, from the
Très Riches Heures du duc de Berry (month of June) (1410)
3.
Second French Empire
–
The Second French Empire was the Imperial Bonapartist regime of Napoleon III from 1852 to 1870, between the Second Republic and the Third Republic, in France. The structure of the French government during the Second Empire was little changed from the First, but Emperor Napoleon III stressed his own imperial role as the foundation of the government. He had so often, while in prison or in exile and his answer was to organize a system of government based on the principles of the Napoleonic Idea. This meant that the emperor, the elect of the people as the representative of the democracy, ruled supreme. He himself drew power and legitimacy from his role as representative of the great Napoleon I of France, the anti-parliamentary French Constitution of 1852 instituted by Napoleon III on 14 January 1852, was largely a repetition of that of 1848. All executive power was entrusted to the emperor, who, as head of state, was responsible to the people. The people of the Empire, lacking democratic rights, were to rely on the benevolence of the rather than on the benevolence of politicians. He was to nominate the members of the council of state, whose duty it was to prepare the laws, and of the senate, a body permanently established as a constituent part of the empire. One innovation was made, namely, that the Legislative Body was elected by universal suffrage and this new political change was rapidly followed by the same consequence as had attended that of Brumaire. The press was subjected to a system of cautionnements and avertissements, in order to counteract the opposition of individuals, a surveillance of suspects was instituted. In the same way public instruction was strictly supervised, the teaching of philosophy was suppressed in the lycées, for seven years France had no democratic life. The Empire governed by a series of plebiscites, up to 1857 the Opposition did not exist, from then till 1860 it was reduced to five members, Darimon, Émile Ollivier, Hénon, Jules Favre and Ernest Picard. On 2 December 1851 Louis-Napoléon Bonaparte, who had been elected President of the Republic and he thus became sole ruler of France, and re-established universal suffrage, previously abolished by the Assembly. His decisions and the extension of his mandate for 10 years were popularly endorsed by a referendum later that month that attracted an implausible 92 percent support. A new constitution was enacted in January 1852 which made Louis-Napoléon president for 10 years, however, he was not content with merely being an authoritarian president. Almost as soon as he signed the new document into law, in response to officially-inspired requests for the return of the empire, the Senate scheduled a second referendum in November, which passed with 97 percent support. As with the December 1851 referendum, most of the yes votes were manufactured out of thin air, the empire was formally re-established on 2 December 1852, and the Prince-President became Napoléon III, Emperor of the French. The constitution concentrated so much power in his hands that the only changes were to replace the word president with the word emperor
Second French Empire
–
Napoléon III
Second French Empire
–
Flag
Second French Empire
–
The official declaration of the Second Empire, at the
Hôtel de Ville de Paris, on December 2, 1852.
4.
Le Croisic
–
Le Croisic, is a commune in the Loire-Atlantique department in western France. The United States Navy established an air station on 27 November 1917 to operate seaplanes during World War I. The base closed shortly after the First Armistice at Compiègne, the writer and historian Auguste Lorieux was born in Le Croisic. La Baule - Guérande Peninsula Communes of the Loire-Atlantique department Ferdinand du Puigaudeau
Le Croisic
–
La côte sauvage.
5.
Brittany
–
Brittany is a cultural region in the north-west of France. Brittany has also referred to as Less, Lesser or Little Britain. It is bordered by the English Channel to the north, the Celtic Sea and the Atlantic Ocean to the west, and its land area is 34,023 km². Since reorganisation in 1956, the administrative region of Brittany comprises only four of the five Breton departments. The remaining area of old Brittany, the Loire-Atlantique department around Nantes, at the 2010 census, the population of historic Brittany was estimated to be 4,475,295. Of these, 71% lived in the region of Brittany, while 29% lived in the Loire-Atlantique department, in 2012, the largest metropolitan areas were Nantes, Rennes, and Brest. Brittany is the homeland of the Breton people and is recognised by the Celtic League as one of the six Celtic nations. A nationalist movement seeks greater autonomy within the French Republic, the word Brittany, along with its French, Breton and Gallo equivalents Bretagne, Breizh and Bertaèyn, derive from the Latin Britannia, which means Britons land. This word had been used by the Romans since the 1st century to refer to Great Britain and this word derives from a Greek word, Πρεττανικη or Βρεττανίαι, used by Pytheas, an explorer from Massalia who visited the British Islands around 320 BC. This term probably comes from a Gallic word, aremorica, which close to the sea. Another name, Letauia, was used until the 12th century and it possibly means wide and flat or to expand and it gave the Welsh name for Brittany, Llydaw. Later, authors like Geoffrey of Monmouth used the terms Britannia minor, breton-speaking people may pronounce the word Breizh in two different ways, according to their region of origin. Breton can be divided into two dialects, the KLT and the dialect of Vannes. KLT speakers pronounce it and would write it Breiz, while the Vannetais speakers pronounce it, the official spelling is a compromise between both variants, with a z and an h together. In 1941, efforts to unify the dialects led to the creation of the so-called Breton zh, on its side, Gallo language has never had a widely accepted writing system and several ones coexist. For instance, the name of the region in that language can be written Bertaèyn in ELG script, or Bertègn in MOGA, Brittany has been inhabited by humans since the Lower Paleolithic. This population was scarce and very similar to the other Neanderthals found in the whole of Western Europe and their only original feature was a distinct culture, called Colombanian. One of the oldest hearths in the world has found in Plouhinec
Brittany
–
The
Carnac stones.
Brittany
Brittany
–
The five Gallic tribes of Brittany.
Brittany
–
The temple of Mars in
Corseul.
6.
French Third Republic
–
It came to an end on 10 July 1940. Harsh reparations exacted by the Prussians after the war resulted in the loss of the French regions of Alsace and Lorraine, social upheaval, and the establishment of the Paris Commune. The early governments of the Third Republic considered re-establishing the monarchy, but confusion as to the nature of that monarchy, thus, the Third Republic, which was originally intended as a provisional government, instead became the permanent government of France. The French Constitutional Laws of 1875 defined the composition of the Third Republic and it consisted of a Chamber of Deputies and a Senate to form the legislative branch of government and a president to serve as head of state. The period from the start of World War I to the late 1930s featured sharply polarized politics, Adolphe Thiers called republicanism in the 1870s the form of government that divides France least, however, politics under the Third Republic were sharply polarized. On the left stood Reformist France, heir to the French Revolution, on the right stood conservative France, rooted in the peasantry, the Roman Catholic Church and the army. The Franco-Prussian War of 1870–1871 resulted in the defeat of France, after Napoleons capture by the Prussians at the Battle of Sedan, Parisian deputies led by Léon Gambetta established the Government of National Defence as a provisional government on 4 September 1870. The deputies then selected General Louis-Jules Trochu to serve as its president and this first government of the Third Republic ruled during the Siege of Paris. After the French surrender in January 1871, the provisional Government of National Defence disbanded, French territories occupied by Prussia at this time did not participate. The resulting conservative National Assembly elected Adolphe Thiers as head of a provisional government, due to the revolutionary and left-wing political climate that prevailed in the Parisian population, the right-wing government chose the royal palace of Versailles as its headquarters. The new government negotiated a settlement with the newly proclaimed German Empire. To prompt the Prussians to leave France, the government passed a variety of laws, such as the controversial Law of Maturities. The following repression of the communards would have consequences for the labor movement. The Orléanists supported a descendant of King Louis Philippe I, the cousin of Charles X who replaced him as the French monarch in 1830, his grandson Louis-Philippe, Comte de Paris. The Bonapartists were marginalized due to the defeat of Napoléon III and were unable to advance the candidacy of any member of his family, the Bonaparte family. Legitimists and Orléanists came to a compromise, eventually, whereby the childless Comte de Chambord would be recognised as king, consequently, in 1871 the throne was offered to the Comte de Chambord. Chambord believed the monarchy had to eliminate all traces of the Revolution in order to restore the unity between the monarchy and the nation, which the revolution had sundered apart. Compromise on this was if the nation were to be made whole again
French Third Republic
–
A French propaganda poster from 1917 is captioned with an 18th century quote: "Even in 1788, Mirabeau was saying that War is the National Industry of Prussia."
French Third Republic
–
Flag
French Third Republic
–
The
Sacré-Cœur Basilica was built as a symbol of the Ordre Moral.
French Third Republic
–
In France, children were taught in school not to forget the lost provinces of
Alsace-Lorraine, which were coloured in black on maps.
7.
French people
–
The French are an ethnic group and nation who are identified with the country of France. This connection may be legal, historical, or cultural, modern French society can be considered a melting pot. To be French, according to the first article of the French Constitution, is to be a citizen of France, regardless of origin, race. The debate concerning the integration of this view with the underlying the European Community remains open. A large number of foreigners have traditionally been permitted to live in France, indeed, the country has long valued its openness, tolerance and the quality of services available. Application for French citizenship is often interpreted as a renunciation of previous state allegiance unless a dual citizenship agreement exists between the two countries, the European treaties have formally permitted movement and European citizens enjoy formal rights to employment in the state sector. Seeing itself as a nation with universal values, France has always valued. However, the success of such assimilation has recently called into question. There is increasing dissatisfaction with, and within, growing ethno-cultural enclaves, the 2005 French riots in some troubled and impoverished suburbs were an example of such tensions. However they should not be interpreted as ethnic conflicts but as social conflicts born out of socioeconomic problems endangering proper integration, the name France etymologically derives from the word Francia, the territory of the Franks. The Franks were a Germanic tribe that overran Roman Gaul at the end of the Roman Empire, in the pre-Roman era, all of Gaul was inhabited by a variety of peoples who were known collectively as the Gaulish tribes. Gaul was militarily conquered in 58-51 BCE by the Roman legions under the command of General Julius Caesar, the area then became part of the Roman Empire. Over the next five centuries the two cultures intermingled, creating a hybridized Gallo-Roman culture, the Gaulish vernacular language disappeared step by step to be replaced everywhere by Vulgar Latin, which would later develop under Frankish influence into the French language in the North of France. With the decline of the Roman Empire in Western Europe, a federation of Germanic peoples entered the picture, the Franks were Germanic pagans who began to settle in northern Gaul as laeti, already during the Roman era. They continued to filter across the Rhine River from present-day Netherlands, at the beginning, they served in the Roman army and reached high commands. Their language is spoken as a kind of Dutch in northern France. Another Germanic people immigrated massively to Alsace, the Alamans, which explains the Alemannic German spoken there and they were competitors of the Franks, thats why it became at the Renaissance time the word for German in French, Allemand. By the early 6th century the Franks, led by the Merovingian king Clovis I and his sons, had consolidated their hold on much of modern-day France, the Vikings eventually intermarried with the local people, converting to Christianity in the process
French people
–
Louis XIV of France "The Sun-King"
French people
–
Row 1:
Joan of Arc
French people
–
Liberty Leading the People by Eugène Delacroix
French people
–
French people in Paris, August 1944
8.
Radioactivity
–
A material containing such unstable nuclei is considered radioactive. Certain highly excited short-lived nuclear states can decay through neutron emission, or more rarely, however, for a collection of atoms, the collections expected decay rate is characterized in terms of their measured decay constants or half-lives. This is the basis of radiometric dating, the half-lives of radioactive atoms have no known upper limit, spanning a time range of over 55 orders of magnitude, from nearly instantaneous to far longer than the age of the universe. A radioactive nucleus with spin can have no defined orientation. If there are multiple particles produced during a single decay, as in decay, their relative angular distribution. Such a parent process could be a previous decay, or a nuclear reaction, the decaying nucleus is called the parent radionuclide, and the process produces at least one daughter nuclide. Except for gamma decay or internal conversion from an excited state. When the number of changes, an atom of a different chemical element is created. The first decay processes to be discovered were alpha decay, beta decay, alpha decay occurs when the nucleus ejects an alpha particle. This is the most common process of emitting nucleons, but highly excited nuclei can eject single nucleons, or in the case of cluster decay, specific light nuclei of other elements. Beta decay occurs when the nucleus emits an electron or positron, the nucleus may capture an orbiting electron, causing a proton to convert into a neutron in a process called electron capture. All of these result in a well-defined nuclear transmutation. By contrast, there are radioactive decay processes that do not result in a nuclear transmutation, another type of radioactive decay results in products that vary, appearing as two or more fragments of the original nucleus with a range of possible masses. For a summary table showing the number of stable and radioactive nuclides in each category, there are 29 naturally occurring chemical elements on Earth that are radioactive. They are those that contain 34 radionuclides that date before the time of formation of the solar system, well-known examples are uranium and thorium, but also included are naturally occurring long-lived radioisotopes, such as potassium-40. Radioactivity was discovered in 1896 by the French scientist Henri Becquerel and these materials glow in the dark after exposure to light, and he suspected that the glow produced in cathode ray tubes by X-rays might be associated with phosphorescence. He wrapped a photographic plate in black paper and placed various phosphorescent salts on it, all results were negative until he used uranium salts. The uranium salts caused a blackening of the plate in spite of the plate being wrapped in black paper and these radiations were given the name Becquerel Rays
Radioactivity
–
Pierre and Marie Curie in their Paris laboratory, before 1907
Radioactivity
–
Alpha decay is one type of radioactive decay, in which an atomic nucleus emits an
alpha particle, and thereby transforms (or "decays") into an atom with a
mass number decreased by 4 and
atomic number decreased by 2.
Radioactivity
–
Taking an X-ray image with early
Crookes tube apparatus in 1896. The Crookes tube is visible in the centre. The standing man is viewing his hand with a
fluoroscope screen; this was a common way of setting up the tube. No precautions against radiation exposure are being taken; its hazards were not known at the time.
Radioactivity
–
Gamma-ray energy spectrum of uranium ore (inset). Gamma-rays are emitted by decaying
nuclides, and the gamma-ray energy can be used to characterize the decay (which nuclide is decaying to which). Here, using the gamma-ray spectrum, several nuclides that are typical of the decay chain of 238 U have been identified: 226 Ra, 214 Pb, 214 Bi.
9.
Nobel Prize in Physics
–
The Nobel Prize in Physics is a yearly award given by the Royal Swedish Academy of Sciences for those who conferred the most outstanding contributions for mankind in the field of physics. The first Nobel Prize in Physics was awarded to German/Dutch physicist Wilhelm Röntgen in recognition of the services he has rendered by the discovery of the remarkable rays. This award is administered by the Nobel Foundation and widely regarded as the most prestigious award that a scientist can receive in physics and it is presented in Stockholm at an annual ceremony on December 10, the anniversary of Nobels death. Through 2016, a total of 203 individuals have been awarded the prize, only two women have won the Nobel Prize in Physics, Marie Curie in 1903, and Maria Goeppert Mayer in 1963. Though Nobel wrote several wills during his lifetime, the last one was written a year before he died and was signed at the Swedish-Norwegian Club in Paris on 27 November 1895. Nobel bequeathed 94% of his assets,31 million Swedish kronor, to establish. Due to the level of surrounding the will, it was not until April 26,1897 that it was approved by the Storting. The executors of his will were Ragnar Sohlman and Rudolf Lilljequist, the members of the Norwegian Nobel Committee who were to award the Peace Prize were appointed shortly after the will was approved. The prize-awarding organisations followed, the Karolinska Institutet on June 7, the Swedish Academy on June 9, the Nobel Foundation then reached an agreement on guidelines for how the Nobel Prize should be awarded. In 1900, the Nobel Foundations newly created statutes were promulgated by King Oscar II, according to Nobels will, The Royal Swedish Academy of sciences were to award the Prize in Physics. A maximum of three Nobel laureates and two different works may be selected for the Nobel Prize in Physics, compared with other Nobel Prizes, the nomination and selection process for the prize in Physics is long and rigorous. This is a key reason why it has grown in importance over the years to become the most important prize in Physics, the Nobel laureates are selected by the Nobel Committee for Physics, a Nobel Committee that consists of five members elected by The Royal Swedish Academy of Sciences. In the first stage begins in September, around 3,000 people – selected university professors, Nobel Laureates in Physics and Chemistry. The completed nomination forms arrive at the Nobel Committee no later than 31 January of the following year and these nominees are scrutinized and discussed by experts who narrow it to approximately fifteen names. The committee submits a report with recommendations on the candidates into the Academy. The Academy then makes the selection of the Laureates in Physics through a majority vote. The names of the nominees are never announced, and neither are they told that they have been considered for the prize. Nomination records are sealed for fifty years, while posthumous nominations are not permitted, awards can be made if the individual died in the months between the decision of the prize committee and the ceremony in December
Nobel Prize in Physics
–
Wilhelm Röntgen (1845–1923), the first recipient of the Nobel Prize in Physics.
Nobel Prize in Physics
–
The Nobel Prize in Physics
Nobel Prize in Physics
–
Three Nobel Laureates in Physics. Front row from left:
Albert A. Michelson (1907),
Albert Einstein (1921) and
Robert A. Millikan (1923).
10.
Fellow of the Royal Society
–
As of 2016, there are around 1600 living Fellows, Foreign and Honorary Members. Fellowship of the Royal Society has been described by The Guardian newspaper as “the equivalent of a lifetime achievement Oscar” with several institutions celebrating their announcement each year. Up to 60 new Fellows, honorary and foreign members are elected annually usually in May, each candidate is considered on their merits and can be proposed from any sector of the scientific community. Fellows are elected for life on the basis of excellence in science and are entitled to use the post-nominal letters FRS, see Category, Fellows of the Royal Society and Category, Female Fellows of the Royal Society. Every year, Fellows elect up to ten new Foreign Members, like Fellows, Foreign Members are elected for life through peer review on the basis of excellence in science. As of 2016 there are around 165 Foreign Members, who are entitled to use the post-nominal ForMemRS, see Category, Foreign Members of the Royal Society. Honorary Fellows include Bill Bryson, Melvyn Bragg, Robin Saxby, David Sainsbury, Baron Sainsbury of Turville, Honorary Fellows are entitled to use the post nominal letters HonFRS. Others including John Maddox, Patrick Moore and Lisa Jardine were elected as honorary fellows, statute 12 is a legacy mechanism for electing members before official honorary membership existed in 1997. Fellows elected under statute 12 include David Attenborough and John Palmer, prime Ministers of the United Kingdom such as Margaret Thatcher, Neville Chamberlain, H. H. Asquith were elected under statute 12, see Category, Fellows of the Royal Society. The Council of the Royal Society can recommend members of the British Royal Family for election as Royal Fellows of the Royal Society. As of 2016 there are five royal fellows, Charles, Prince of Wales, Anne, Princess Royal, Prince Edward, Duke of Kent, Prince William, Duke of Cambridge and Prince Andrew, Duke of York. Her Majesty the Queen, Elizabeth II is not a Royal Fellow, Prince Philip, Duke of Edinburgh was elected under statute 12, not as a Royal Fellow. The election of new fellows is announced annually in May, after their nomination, each candidate for Fellowship or Foreign Membership is nominated by two Fellows of the Royal Society, who sign a certificate of proposal. Previously, nominations required at least five fellows to support each nomination by the proposer, the certificate of election includes a statement of the principal grounds on which the proposal is being made. There is no limit on the number of nominations each year. In 2015, there were 654 candidates for election as Fellows and 106 candidates for Foreign Membership. The final list of up to 52 Fellowship candidates and up to 10 Foreign Membership candidates is confirmed by the Council in April, a candidate is elected if he or she secures two-thirds of votes of those Fellows present and voting. A further maximum of six can be ‘Honorary’, ‘General’ or ‘Royal’ Fellows, nominations for Fellowship are peer reviewed by sectional committees, each with fifteen members and a chair
Fellow of the Royal Society
–
The entrance to the Royal Society in Carlton House Terrace, London
Fellow of the Royal Society
–
The President, Council, and Fellows of the Royal Society of London for Improving Natural Knowledge
Fellow of the Royal Society
–
John Evelyn, who helped to found the Royal Society
Fellow of the Royal Society
–
Mace granted by Charles II
11.
Physics
–
Physics is the natural science that involves the study of matter and its motion and behavior through space and time, along with related concepts such as energy and force. One of the most fundamental disciplines, the main goal of physics is to understand how the universe behaves. Physics is one of the oldest academic disciplines, perhaps the oldest through its inclusion of astronomy, Physics intersects with many interdisciplinary areas of research, such as biophysics and quantum chemistry, and the boundaries of physics are not rigidly defined. New ideas in physics often explain the mechanisms of other sciences while opening new avenues of research in areas such as mathematics. Physics also makes significant contributions through advances in new technologies that arise from theoretical breakthroughs, the United Nations named 2005 the World Year of Physics. Astronomy is the oldest of the natural sciences, the stars and planets were often a target of worship, believed to represent their gods. While the explanations for these phenomena were often unscientific and lacking in evidence, according to Asger Aaboe, the origins of Western astronomy can be found in Mesopotamia, and all Western efforts in the exact sciences are descended from late Babylonian astronomy. The most notable innovations were in the field of optics and vision, which came from the works of many scientists like Ibn Sahl, Al-Kindi, Ibn al-Haytham, Al-Farisi and Avicenna. The most notable work was The Book of Optics, written by Ibn Al-Haitham, in which he was not only the first to disprove the ancient Greek idea about vision, but also came up with a new theory. In the book, he was also the first to study the phenomenon of the pinhole camera, many later European scholars and fellow polymaths, from Robert Grosseteste and Leonardo da Vinci to René Descartes, Johannes Kepler and Isaac Newton, were in his debt. Indeed, the influence of Ibn al-Haythams Optics ranks alongside that of Newtons work of the same title, the translation of The Book of Optics had a huge impact on Europe. From it, later European scholars were able to build the devices as what Ibn al-Haytham did. From this, such important things as eyeglasses, magnifying glasses, telescopes, Physics became a separate science when early modern Europeans used experimental and quantitative methods to discover what are now considered to be the laws of physics. Newton also developed calculus, the study of change, which provided new mathematical methods for solving physical problems. The discovery of new laws in thermodynamics, chemistry, and electromagnetics resulted from greater research efforts during the Industrial Revolution as energy needs increased, however, inaccuracies in classical mechanics for very small objects and very high velocities led to the development of modern physics in the 20th century. Modern physics began in the early 20th century with the work of Max Planck in quantum theory, both of these theories came about due to inaccuracies in classical mechanics in certain situations. Quantum mechanics would come to be pioneered by Werner Heisenberg, Erwin Schrödinger, from this early work, and work in related fields, the Standard Model of particle physics was derived. Areas of mathematics in general are important to this field, such as the study of probabilities, in many ways, physics stems from ancient Greek philosophy
Physics
–
Further information:
Outline of physics
Physics
–
Ancient
Egyptian astronomy is evident in monuments like the
ceiling of Senemut's tomb from the
Eighteenth Dynasty of Egypt.
Physics
–
Sir Isaac Newton (1643–1727), whose
laws of motion and
universal gravitation were major milestones in classical physics
Physics
–
Albert Einstein (1879–1955), whose work on the
photoelectric effect and the
theory of relativity led to a revolution in 20th century physics
12.
Chemistry
–
Chemistry is a branch of physical science that studies the composition, structure, properties 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, metallurgy, philosophy, astrology, astronomy, mysticism. An alchemist was called a chemist in popular speech, and later 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, pottery 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, though, 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, later 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
Chemistry
–
Solutions of substances in reagent bottles, including
ammonium hydroxide and
nitric acid, illuminated in different colors
Chemistry
–
Democritus ' atomist philosophy was later adopted by
Epicurus (341–270 BCE).
Chemistry
–
Antoine-Laurent de Lavoisier is considered the "Father of Modern Chemistry".
Chemistry
–
Laboratory, Institute of Biochemistry,
University of Cologne.
13.
A. E. Becquerel
–
Alexandre-Edmond Becquerel, known as Edmond Becquerel, was a French physicist who studied the solar spectrum, magnetism, electricity and optics. He is credited with the discovery of the effect, the operating principle of the solar cell. He is also known for his work in luminescence and phosphorescence and he was the son of Antoine César Becquerel and the father of Henri Becquerel, one of the discoverers of radioactivity. Becquerel was born in Paris and was in turn the pupil, assistant and he was also appointed professor at the short-lived Agronomic Institute at Versailles in 1849, and in 1853 received the chair of physics at the Conservatoire des Arts et Métiers. He was associated with his father in much of his work, in 1839, at age 19, experimenting in his fathers laboratory, Becquerel created the worlds first photovoltaic cell. In this experiment, silver chloride was placed in a solution and illuminated while connected to platinum electrodes, generating voltage. Because of this work, the effect has also been known as the Becquerel effect. Becquerel was an experimenter in photography. In practice this technique was rarely used, in 1867 and 1868 Becquerel published La lumière, ses causes et ses effets, a two-volume treatise which became a standard text. His many papers and commentaries appeared in French scientific journals, mainly the French Academy of Sciences widely distributed Comptes Rendus, Becquerel was elected a member of the Royal Swedish Academy of Sciences in 1886. The Becquerel Prize for outstanding merit in photovoltaics is awarded annually at the European Photovoltaic Solar Energy Conference, Henri Becquerel, The Discovery of Radioactivity. Works by or about Edmond Becquerel at Internet Archive Works in Open Library
A. E. Becquerel
–
Edmond Becquerel
14.
Nobel laureate
–
They were established by the 1895 will of Alfred Nobel, which dictates that the awards should be administered by the Nobel Foundation. The Nobel Memorial Prize in Economic Sciences was established in 1968 by the Sveriges Riksbank, each recipient, or laureate, receives a gold medal, a diploma, and a sum of money, which is decided by the Nobel Foundation, yearly. Each recipient receives a medal, a diploma and an award that has varied throughout the years. In 1901, the recipients of the first Nobel Prizes were given 150,782 SEK, in 2008, the laureates were awarded a prize amount of 10,000,000 SEK. The awards are presented in Stockholm in a ceremony on December 10. In years in which the Nobel Prize is not awarded due to events or a lack of nominations. The Nobel Prize was not awarded between 1940 and 1942 due to the outbreak of World War II, between 1901 and 2015, the Nobel Prizes and the Nobel Memorial Prize in Economic Sciences were awarded 573 times to 900 people and organizations. With some receiving the Nobel Prize more than once, this makes a total of 870 individuals and 23 organizations, four Nobel laureates were not permitted by their governments to accept the Nobel Prize. Six laureates have received more than one prize, of the six, UNHCR has been awarded the Nobel Peace Prize twice. Also the Nobel Prize in Physics was awarded to John Bardeen twice, two laureates have been awarded twice but not in the same field, Marie Curie and Linus Pauling. Among the 870 Nobel laureates,48 have been women, the first woman to receive a Nobel Prize was Marie Curie and she was also the first person to be awarded two Nobel Prizes, the second award being the Nobel Prize in Chemistry, given in 1911. A In 1938 and 1939, the government of Germany did not allow three German Nobel nominees to accept their Nobel Prizes. The three were Richard Kuhn, Nobel laureate in Chemistry in 1938, Adolf Butenandt, Nobel laureate in Chemistry in 1939 and they were later awarded the Nobel Prize diploma and medal, but not the money. B In 1948, the Nobel Prize in Peace was not awarded, the Nobel Foundations website suggests that it would have been awarded to Mohandas Karamchand Gandhi, however, due to his assassination earlier that year, it was left unassigned in his honor. C In 1958, Russian-born Boris Pasternak, under pressure from the government of the Soviet Union, was forced to decline the Nobel Prize in Literature. D In 1964, Jean-Paul Sartre refused to accept the Nobel Prize in Literature, E In 1973, Lê Ðức Thọ declined the Nobel Peace Prize. His reason was that he felt he did not deserve it because although he helped negotiate the Paris Peace Accords, F In 2010, Liu Xiaobo was unable to receive the Nobel Peace Prize as he was sentenced to 11 years of imprisonment by the Chinese authorities
Nobel laureate
–
Nobel laureates of 2012
Alvin E. Roth,
Brian Kobilka,
Robert J. Lefkowitz,
David J. Wineland, and
Serge Haroche during the ceremony
Nobel laureate
–
Nobel laureates receive a gold medal together with a diploma and (as of 2012) 8 million
SEK (roughly US$1.2 million, €0.93 million).
15.
Pierre Curie
–
Pierre Curie was a French physicist, a pioneer in crystallography, magnetism, piezoelectricity and radioactivity. Born in Paris on 15 May 1859, Pierre was the son of Eugène Curie and he was educated by his father, a doctor, and in his early teens showed a strong aptitude for mathematics and geometry. When he was 16, he earned his math degree, by the age of 18 he had completed the equivalent of a higher degree, but did not proceed immediately to a doctorate due to lack of money. Instead he worked as a laboratory instructor, in 1880, Pierre and his older brother Jacques demonstrated that an electric potential was generated when crystals were compressed, i. e. piezoelectricity. To provide accurate measurements needed for their work, Pierre created a highly sensitive instrument called the Curie Scale and he used weights, microscopic meter readers, and pneumatic dampeners to create the scale. Also, to aid their work, they invented the Piezoelectric Quartz Electrometer, shortly afterwards, in 1881, they demonstrated the reverse effect, that crystals could be made to deform when subject to an electric field. Almost all digital electronic circuits now rely on this in the form of crystal oscillators, Pierre Curie was introduced to Maria Skłodowska by their friend, physicist Józef Wierusz-Kowalski. Pierre took Maria into his laboratory as his student and his admiration for her grew when he realized that she would not inhibit his research. He began to regard her as his muse and she refused his initial proposal, but finally agreed to marry him on 26 July 1895. It would be a thing, a thing I dare not hope, if we could spend our life near each other hypnotized by our dreams, your patriotic dream, our humanitarian dream. Pierre Curie to Marie Skłodowska Prior to his famous studies on magnetism. Variations on this equipment were used by future workers in that area. Pierre Curie studied ferromagnetism, paramagnetism, and diamagnetism for his doctoral thesis, the material constant in Curies law is known as the Curie constant. He also discovered that ferromagnetic substances exhibited a critical temperature transition and this is now known as the Curie temperature. The Curie temperature is used to plate tectonics, treat hypothermia, measure caffeine. Pierre formulated what is now known as the Curie Dissymmetry Principle, for example, a random mixture of sand in zero gravity has no dissymmetry. Introduce a gravitational field, and there is a dissymmetry because of the direction of the field, then the sand grains can self-sort with the density increasing with depth. But this new arrangement, with the arrangement of sand grains
Pierre Curie
–
Pierre Curie
Pierre Curie
–
Propriétés magnétiques des corps à diverses temperatures (Curie's dissertation, 1895)
Pierre Curie
–
The crypt at the Panthéon in Paris
16.
SI derived unit
–
The International System of Units specifies a set of seven base units from which all other SI units of measurement are derived. Each of these units is either dimensionless or can be expressed as a product of powers of one or more of the base units. For example, the SI derived unit of area is the metre. The degree Celsius has an unclear status, and is arguably an exception to this rule. The names of SI units are written in lowercase, the symbols for units named after persons, however, are always written with an uppercase initial letter. In addition to the two dimensionless derived units radian and steradian,20 other derived units have special names, some other units such as the hour, litre, tonne, bar and electronvolt are not SI units, but are widely used in conjunction with SI units. Until 1995, the SI classified the radian and the steradian as supplementary units, but this designation was abandoned, International System of Quantities International System of Units International Vocabulary of Metrology Metric prefix Metric system Non-SI units mentioned in the SI Planck units SI base unit I. Mills, Tomislav Cvitas, Klaus Homann, Nikola Kallay, IUPAC, Quantities, Units and Symbols in Physical Chemistry. CS1 maint, Multiple names, authors list
SI derived unit
–
Base units
17.
Becquerel
–
The becquerel is the SI derived unit of radioactivity. One becquerel is defined as the activity of a quantity of material in which one nucleus decays per second. The becquerel is therefore equivalent to a second, s−1. The becquerel is named after Henri Becquerel, who shared a Nobel Prize in Physics with Pierre, as with every International System of Units unit named for a person, the first letter of its symbol is uppercase. 1 Bq =1 s−1 A special name was introduced for the second to represent radioactivity to avoid potentially dangerous mistakes with prefixes. For example,1 µs−1 could be taken to mean 106 disintegrations per second, other names considered were hertz, a special name already in use for the reciprocal second, and fourier. The hertz is now used for periodic phenomena. Whereas 1 Hz is 1 cycle per second,1 Bq is 1 aperiodic radioactivity event per second, the gray and the becquerel were introduced in 1975. Between 1953 and 1975, absorbed dose was often measured in rads, decay activity was measured in curies before 1946 and often in rutherfords between 1946 and 1975. Like any SI unit, Bq can be prefixed, commonly used multiples are kBq, MBq, GBq, TBq, for practical applications,1 Bq is a small unit, therefore, the prefixes are common. For example, the roughly 0.0169 g of potassium-40 present in a human body produces approximately 4,400 disintegrations per second or 4.4 kBq of activity. The global inventory of carbon-14 is estimated to be 8. 5×1018 Bq, the nuclear explosion in Hiroshima is estimated to have produced 8×1024 Bq. The becquerel succeeded the curie, an older, non-SI unit of radioactivity based on the activity of 1 gram of radium-226, the curie is defined as 3. 7·1010 s−1, or 37 GBq. The following table shows radiation quantities in SI and non-SI units
Becquerel
–
Graphic showing relationships between radioactivity and detected ionizing radiation
18.
Plane polarization
–
The orientation of a linearly polarized electromagnetic wave is defined by the direction of the electric field vector. For example, if the field vector is vertical the radiation is said to be vertically polarized. Here ∣ E ∣ is the amplitude of the field and | ψ ⟩ = d e f = is the Jones vector in the x-y plane. The wave is polarized when the phase angles α x, α y are equal. This represents a wave polarized at an angle θ with respect to the x axis, in that case, the Jones vector can be written | ψ ⟩ = exp . The state vectors for linear polarization in x or y are special cases of this state vector, sinusoidal plane-wave solutions of the electromagnetic wave equation Polarization Circular polarization Elliptical polarization Photon polarization Jackson, John D
Plane polarization
–
Diagram of the electric field of a light wave (blue), linear-polarized along a plane (purple line), and consisting of two orthogonal, in-phase components (red and green waves)
19.
Phosphorescence
–
Phosphorescence is a type of photoluminescence related to fluorescence. Unlike fluorescence, phosphorescent material does not immediately re-emit the radiation it absorbs, the slower time scales of the re-emission are associated with forbidden energy state transitions in quantum mechanics. As these transitions occur very slowly in certain materials, absorbed radiation is re-emitted at an intensity for up to several hours after the original excitation. Typically, the glow slowly fades out, sometimes within a few minutes or up to a few hours in a dark room, the study of phosphorescent materials led to the discovery of radioactivity in 1896. In simple terms, phosphorescence is a process in which energy absorbed by a substance is released relatively slowly in the form of light and this is in some cases the mechanism used for glow-in-the-dark materials which are charged by exposure to light. Most photoluminescent events, in which a chemical substrate absorbs and then re-emits a photon of light, are fast, light is absorbed and emitted at these fast time scales in cases where the energy of the photons involved matches the available energy states and allowed transitions of the substrate. In the special case of phosphorescence, the photon energy undergoes an unusual intersystem crossing into an energy state of higher spin multiplicity. As a result, the energy can become trapped in the state with only forbidden transitions available to return to the lower energy state. These transitions, although forbidden, will occur in quantum mechanics but are kinetically unfavored. Most phosphorescent compounds are relatively fast emitters, with triplet lifetimes on the order of milliseconds. However, some compounds have triplet lifetimes up to minutes or even hours, if the phosphorescent quantum yield is high, these substances will release significant amounts of light over long time scales, creating so-called glow-in-the-dark materials. S0 + h ν → S1 → T1 → S0 + h ν ′ where S is a singlet, transitions can also occur to higher energy levels, but the first excited state is denoted for simplicity. Some examples of glow-in-the-dark materials do not glow by phosphorescence, for example, glow sticks glow due to a chemiluminescent process which is commonly mistaken for phosphorescence. In chemiluminescence, a state is created via a chemical reaction. The light emission tracks the progress of the underlying chemical reaction. The excited state will then transfer to a dye molecule, also known as a sensitizer or fluorophor, common pigments used in phosphorescent materials include zinc sulfide and strontium aluminate. Use of zinc sulfide for safety related products dates back to the 1930s, however, the development of strontium aluminate, with a luminance approximately 10 times greater than zinc sulfide, has relegated most zinc sulfide based products to the novelty category. Strontium aluminate based pigments are now used in signs, pathway marking
Phosphorescence
–
Phosphorescent, Europium-doped strontium silicate-aluminate oxide powder under visible light, long-wave UV light, and in total darkness
Phosphorescence
Phosphorescence
–
An extremely intense pulse of UV light in a
flashtube produced this blue phosphorescence in the
fused silica envelope.
Phosphorescence
–
Phosphorescence of the quartz ignition tube of an
air-gap flash
20.
Absorption (electromagnetic radiation)
–
In physics, absorption of electromagnetic radiation is the way in which the energy of a photon is taken up by matter, typically the electrons of an atom. Thus, the energy is transformed into internal energy of the absorber. The reduction in intensity of a wave propagating through a medium by absorption of a part of its photons is often called attenuation. The mass attenuation coefficient, also called mass extinction coefficient, which is the absorption coefficient divided by density, the absorption cross section and scattering cross-section are closely related to the absorption and attenuation coefficients, respectively. Extinction in astronomy is equivalent to the attenuation coefficient, absorbance and optical depth are two related measures All these quantities measure, at least to some extent, how well a medium absorbs radiation. However, practitioners of different fields and techniques tend to use different quantities drawn from the list above. The absorbance of an object quantifies how much of the incident light is absorbed by it and this may be related to other properties of the object through the Beer–Lambert law. A few examples of absorption are ultraviolet–visible spectroscopy, infrared spectroscopy, understanding and measuring the absorption of electromagnetic radiation has a variety of applications. Here are a few examples, In meteorology and climatology, global and local temperatures depend in part on the absorption of radiation by gases and land. In medicine, X-rays are absorbed to different extents by different tissues, for example, see computation of radiowave attenuation in the atmosphere used in satellite link design. In chemistry and materials science, because different materials and molecules will absorb radiation to different extents at different frequencies, in optics, sunglasses, colored filters, dyes, and other such materials are designed specifically with respect to which visible wavelengths they absorb, and in what proportions. In physics, the D-region of Earths ionosphere is known to significantly absorb radio signals that fall within the electromagnetic spectrum. Optical Propagation in Linear Media, Atmospheric Gases and Particles, Solid-State Components, physics Archive - Ask a scientist
Absorption (electromagnetic radiation)
21.
Serendipity
–
Serendipity means a fortunate happenstance or pleasant surprise. It was coined by Horace Walpole in 1754, in a letter he wrote to a friend, Walpole explained an unexpected discovery he had made by reference to a Persian fairy tale, The Three Princes of Serendip. The princes, he told his correspondent, were always making discoveries, by accidents and sagacity, in June 2004, a British translation company voted the word to be one of the ten English words hardest to translate. However, due to its use, the word has since been exported into many other languages. The first noted use of serendipity in the English language was by Horace Walpole, the name comes from Serendip, an old name for Sri Lanka, from Old-Tamil Cherantivu, which means Island of Cheras referring to the ancient Naga people. Parts of Sri Lanka were under the rule of Tamil kings for extended periods of time in history, Kings of Kerala, India, were called Chera Kings and divu, tivu or dheep, which means island. The island belonging to the Chera King was called Cherandeep, hence Sarandib by Arab traders. Serendipity is not just a matter of an event, nor can it be taken simply as a synonym for a happy accident, finding out things without being searching for them. The chance is an event, serendipity a capacity, the Nobel Prize laureate Paul Flory suggests that significant inventions are not mere accidents. Successful researchers can observe scientific results with careful attention to analyzing a phenomenon under the most diverse and they can question themselves on assumptions that do not fit with empirical observations. Various thinkers discuss the role that luck can play in science, indeed, the scientific method, and the scientists themselves, can be prepared in many other ways to harness luck and make discoveries. Serendipity is postulated by Napier and Vuong as an advantage with which a firm can tap its potential creativity. Serendipity is a key concept in competitive intelligence because it is one of the tools for avoiding blind spots, the book is a study in sociological semantics and the sociology of science, as the subtitle of the book declares. It further develops the idea of serendipity as scientific method, william Boyd coined the term zemblanity to mean somewhat the opposite of serendipity, making unhappy, unlucky and expected discoveries occurring by design. A zemblanity is, effectively, an unpleasant unsurprise and it derives from Novaya Zemlya, a cold, barren land with many features opposite to the lush Sri Lanka. On this island Willem Barents and his crew were stranded while searching for a new route to the east, bahramdipity is derived directly from Bahram Gur as characterized in the The Three Princes of Serendip. It describes the suppression of serendipitous discoveries or research results by powerful individuals, browse Chance Coincidence Insight Lateral thinking Multiple discovery Remer, Theodore G. ed. Serendipity and the Three Princes, from the Peregrinaggio of 1557. Edited, with an Introduction and Notes, by Theodore G. Remer, LCC 65-10112 Merton, Robert K. Barber, Elinor
Serendipity
–
The photo was intended to be of a
black-crowned night heron; the photographer was initially unaware of the
pileated woodpecker flashing through.
22.
X-rays
–
X-radiation is a form of electromagnetic radiation. Most X-rays have a wavelength ranging from 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz, X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays. Spelling of X-ray in the English language includes the variants x-ray, xray, X-rays with high photon energies are called hard X-rays, while those with lower energy are called soft X-rays. Due to their ability, hard X-rays are widely used to image the inside of objects, e. g. in medical radiography. The term X-ray is metonymically used to refer to an image produced using this method. Since the wavelengths of hard X-rays are similar to the size of atoms they are useful for determining crystal structures by X-ray crystallography. By contrast, soft X-rays are easily absorbed in air, the length of 600 eV X-rays in water is less than 1 micrometer. There is no consensus for a definition distinguishing between X-rays and gamma rays, one common practice is to distinguish between the two types of radiation based on their source, X-rays are emitted by electrons, while gamma rays are emitted by the atomic nucleus. This definition has problems, other processes also can generate these high-energy photons. One common alternative is to distinguish X- and gamma radiation on the basis of wavelength, with radiation shorter than some arbitrary wavelength, such as 10−11 m and this criterion assigns a photon to an unambiguous category, but is only possible if wavelength is known. Occasionally, one term or the other is used in specific contexts due to precedent, based on measurement technique. Thus, gamma-rays generated for medical and industrial uses, for radiotherapy, in the ranges of 6–20 MeV. X-ray photons carry enough energy to ionize atoms and disrupt molecular bonds and this makes it a type of ionizing radiation, and therefore harmful to living tissue. A very high radiation dose over a period of time causes radiation sickness. In medical imaging this increased risk is generally greatly outweighed by the benefits of the examination. The ionizing capability of X-rays can be utilized in treatment to kill malignant cells using radiation therapy. It is also used for material characterization using X-ray spectroscopy, hard X-rays can traverse relatively thick objects without being much absorbed or scattered. For this reason, X-rays are widely used to image the inside of visually opaque objects, the most often seen applications are in medical radiography and airport security scanners, but similar techniques are also important in industry and research
X-rays
–
Spectrum of the X-rays emitted by an X-ray tube with a
rhodium target, operated at 60
kV. The smooth, continuous curve is due to
bremsstrahlung, and the spikes are
characteristic K lines for rhodium atoms.
X-rays
–
X-rays are part of the
electromagnetic spectrum, with wavelengths shorter than
visible light. Different applications use different parts of the X-ray spectrum.
X-rays
–
A
chest radiograph of a female, demonstrating a
hiatus hernia
X-rays
–
An arm radiograph, demonstrating broken
ulna and
radius with implanted
internal fixation.
23.
Uranium
–
Uranium is a chemical element with symbol U and atomic number 92. It is a metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons, Uranium is weakly radioactive because all its isotopes are unstable. The most common isotopes in natural uranium are uranium-238 and uranium-235, Uranium has the highest atomic weight of the primordially occurring elements. Its density is about 70% higher than that of lead, and it occurs naturally in low concentrations of a few parts per million in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite. In nature, uranium is found as uranium-238, uranium-235, Uranium decays slowly by emitting an alpha particle. The half-life of uranium-238 is about 4.47 billion years, many contemporary uses of uranium exploit its unique nuclear properties. Uranium-235 is the naturally occurring fissile isotope, which makes it widely used in nuclear power plants. However, because of the amounts found in nature, uranium needs to undergo enrichment so that enough uranium-235 is present. Uranium-238 is fissionable by fast neutrons, and is fertile, meaning it can be transmuted to fissile plutonium-239 in a nuclear reactor, another fissile isotope, uranium-233, can be produced from natural thorium and is also important in nuclear technology. In sufficient concentration, these maintain a sustained nuclear chain reaction. This generates the heat in nuclear reactors, and produces the fissile material for nuclear weapons. Depleted uranium is used in kinetic energy penetrators and armor plating, Uranium is used as a colorant in uranium glass, producing lemon yellow to green colors. Uranium glass fluoresces green in ultraviolet light and it was also used for tinting and shading in early photography. The 1789 discovery of uranium in the mineral pitchblende is credited to Martin Heinrich Klaproth, eugène-Melchior Péligot was the first person to isolate the metal and its radioactive properties were discovered in 1896 by Henri Becquerel. An ensuing arms race during the Cold War between the United States and the Soviet Union produced tens of thousands of weapons that used uranium metal. The security of those weapons and their fissile material following the breakup of the Soviet Union in 1991 is a concern for public health. When refined, uranium is a white, weakly radioactive metal
Uranium
–
Uranium, 92 U
Uranium
–
Depleted uranium is used by various militaries as high-density penetrators
Uranium
–
The most visible civilian use of uranium is as the thermal power source used in
nuclear power plants
Uranium
–
Uranium glass glowing under
UV light
24.
French Academy of Sciences
–
The French Academy of Sciences is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French scientific research. It was at the forefront of developments in Europe in the 17th and 18th centuries. Currently headed by Sébastien Candel, it is one of the five Academies of the Institut de France, the Academy of Sciences makes its origin to Colberts plan to create a general academy. He chose a group of scholars who met on 22 December 1666 in the Kings library. The first 30 years of the Academys existence were relatively informal, in contrast to its British counterpart, the Academy was founded as an organ of government. The Academy was expected to remain apolitical, and to avoid discussion of religious, on 20 January 1699, Louis XIV gave the Company its first rules. The Academy received the name of Royal Academy of Sciences and was installed in the Louvre in Paris, following this reform, the Academy began publishing a volume each year with information on all the work done by its members and obituaries for members who had died. This reform also codified the method by which members of the Academy could receive pensions for their work, on 8 August 1793, the National Convention abolished all the academies. Almost all the old members of the previously abolished Académie were formally re-elected, among the exceptions was Dominique, comte de Cassini, who refused to take his seat. In 1816, the again renamed Royal Academy of Sciences became autonomous, while forming part of the Institute of France, in the Second Republic, the name returned to Académie des sciences. During this period, the Academy was funded by and accountable to the Ministry of Public Instruction, the Academy came to control French patent laws in the course of the eighteenth century, acting as the liaison of artisans knowledge to the public domain. As a result, academicians dominated technological activities in France, the Academy proceedings were published under the name Comptes rendus de lAcadémie des sciences. The Comptes rendus is now a series with seven titles. The publications can be found on site of the French National Library, in 1818 the French Academy of Sciences launched a competition to explain the properties of light. The civil engineer Augustin-Jean Fresnel entered this competition by submitting a new theory of light. Siméon Denis Poisson, one of the members of the judging committee, being a supporter of the particle-theory of light, he looked for a way to disprove it. The Poisson spot is not easily observed in every-day situations, so it was natural for Poisson to interpret it as an absurd result. However, the head of the committee, Dominique-François-Jean Arago, and he molded a 2-mm metallic disk to a glass plate with wax
French Academy of Sciences
–
A heroic depiction of the activities of the Academy from 1698
French Academy of Sciences
–
Colbert Presenting the Members of the Royal Academy of Sciences to Louis XIV in 1667
French Academy of Sciences
–
The
Institut de France in Paris where the Academy is housed
25.
Thorium
–
Thorium is a chemical element with symbol Th and atomic number 90. A radioactive actinide metal, thorium is one of only two significantly radioactive elements that occur naturally in large quantities as a primordial element. It was discovered in 1829 by the Norwegian amateur mineralogist Morten Thrane Esmark and identified by the Swedish chemist Jöns Jacob Berzelius, who named it after Thor, a thorium atom has 90 protons and therefore 90 electrons, of which four are valence electrons. Thorium metal is silvery and tarnishes black when exposed to air, Thorium is weakly radioactive, all of its known isotopes are unstable. Thorium-232, which has 142 neutrons, is the most stable isotope of thorium and accounts for all natural thorium. Thorium is estimated to be three to four times more abundant than uranium in the Earths crust, and is chiefly refined from monazite sands as a by-product of extracting rare earth metals. Thorium was once used as the light source in gas mantles and as an alloying material. Thorium is still used as an alloying element in TIG welding electrodes. Thorium is predicted to be able to replace uranium as fuel in nuclear reactors. Thorium is a soft, paramagnetic, bright silvery radioactive actinide metal, in the periodic table, it is located to the right of the actinide actinium, to the left of the actinide protactinium, and below the lanthanide cerium. Pure thorium is very ductile and, as normal for metals, can be cold-rolled, swaged, at room temperature, thorium metal has a face-centred cubic crystal structure, additionally, it has two other forms at exotic conditions, one at high temperature and one at high pressure. The properties of thorium vary widely depending on the amount of impurities in the sample, the purest thorium specimens usually contain about a tenth of a percent of the dioxide. These values lie intermediate between those of its neighbours actinium and protactinium, showing the continuity of trends across the early actinides, thoriums melting point of 1750 °C is above both that of actinium and that of protactinium. After thorium, there is a new smooth trend downward in the points of the early actinides from thorium to plutonium where the number of f electrons increases from about 0. Thorium has a modulus of 54 GPa, comparable to those of tin. The hardness of thorium is similar to that of steel, so heated pure thorium can be rolled in sheets. Nevertheless, while thorium is nearly half as dense as uranium and plutonium, Thorium becomes superconductive below 1.4 K. Thorium can also form alloys with many other metals. With chromium and uranium, it forms eutectic mixtures, and thorium is completely miscible in both solid and liquid states with its lighter congener cerium, as such, 232Th still occurs naturally today, four-fifths of the thorium present at Earths formation has survived to the present
Thorium
–
Thorium, 90 Th
Thorium
–
Thor, the namesake of thorium
Thorium
–
The
radiogenic heat from the decay of 232 Th is a major contributor to the
earth's internal heat budget. The other major contributors are
235U,
238U, and
40K.
Thorium
–
Monazite – a major thorium mineral
26.
Polonium
–
Polonium is a chemical element with symbol Po and atomic number 84. Though slightly longer-lived isotopes exist, they are more difficult to produce. Today, polonium is usually produced in quantities by the neutron irradiation of bismuth. Due to its radioactivity, which results in the radiolysis of chemical bonds and radioactive self-heating. Polonium was discovered in 1898 by Marie and Pierre Curie, when it was extracted from ore and identified solely by its strong radioactivity. Polonium was named after Marie Curies homeland of Poland, Polonium has few applications, and those are related to its radioactivity, heaters in space probes, antistatic devices, and sources of neutrons and alpha particles. Poloniums intense radioactivity makes it dangerously toxic, Polonium has 33 known isotopes, all of which are radioactive. They have atomic masses that range from 188 to 220 u. 210Po is the most widely available, the longer-lived 209Po and 208Po can be made through the alpha, proton, or deuteron bombardment of lead or bismuth in a cyclotron. 210Po is an alpha emitter that has a half-life of 138.4 days, it directly to its stable daughter isotope. A milligram of 210Po emits about as many alpha particles per second as 5 grams of 226Ra, a few curies of 210Po emit a blue glow which is caused by ionisation of the surrounding air. About one in 100,000 alpha emissions causes an excitation in the nucleus which results in the emission of a gamma ray with a maximum energy of 803 keV. Polonium is an element that exists in two metallic allotropes. The alpha form is the known example of a simple cubic crystal structure in a single atom basis, with an edge length of 335.2 picometers. The structure of polonium has been characterized by X-ray diffraction and electron diffraction, more than one hypothesis exists for how polonium does this, one suggestion is that small clusters of polonium atoms are spalled off by the alpha decay. The chemistry of polonium is similar to that of tellurium, although it shows some similarities to its neighbor bismuth due to its metallic character. Polonium dissolves readily in dilute acids but is slightly soluble in alkalis. Polonium solutions are first colored in pink by the Po2+ ions, Polonium has no common compounds, and almost all of its compounds are synthetically created, more than 50 of those are known. The most stable class of compounds are polonides, which are prepared by direct reaction of two elements
Polonium
–
Polonium, 84 Po
Polonium
–
The alpha form of solid polonium.
27.
Radium
–
Radium is a chemical element with symbol Ra and atomic number 88. It is the element in group 2 of the periodic table. Pure radium is silvery-white, but it combines with nitrogen on exposure to air. All isotopes of radium are highly radioactive, with the most stable isotope being radium-226, when radium decays, ionizing radiation is a product, which can excite fluorescent chemicals and cause radioluminescence. Radium, in the form of chloride, was discovered by Marie. They extracted the radium compound from uraninite and published the discovery at the French Academy of Sciences five days later, Radium was isolated in its metallic state by Marie Curie and André-Louis Debierne through the electrolysis of radium chloride in 1911. In nature, radium is found in uranium and thorium ores in trace amounts as small as a seventh of a gram per ton of uraninite. Radium is not necessary for living organisms, and adverse effects are likely when it is incorporated into biochemical processes because of its radioactivity. Today, these applications are no longer in vogue because radiums toxicity has since become known. Radium is the heaviest known alkaline earth metal and is the only member of its group. Its physical and chemical properties most closely resemble its lighter congener barium, pure radium is a volatile silvery-white metal, although its lighter congeners calcium, strontium, and barium have a slight yellow tint. Its color rapidly vanishes in air, yielding a layer of radium nitride. Its melting point is either 700 °C or 960 °C and its point is 1,737 °C. Both of these values are lower than those of barium. Like barium and the metals, radium crystallizes in the body-centered cubic structure at standard temperature and pressure. Radium has a density of 5, Radium, like barium, is a highly reactive metal and always exhibits its group oxidation state of +2. It forms the colorless Ra2+ cation in aqueous solution, which is highly basic, the values for barium and radium are almost exactly the same as those of the heavier alkali metals potassium, rubidium, and caesium. Solid radium compounds are white as radium ions provide no specific coloring, insoluble radium compounds coprecipitate with all barium, most strontium, and most lead compounds
Radium
–
Radium, 88 Ra
Radium
–
Marie and Pierre Curie experimenting with radium, a drawing by
André Castaigne
Radium
–
Glass tube of radium chloride kept by the US Bureau of Standards that served as the primary standard of radioactivity for the United States in 1927.
Radium
–
Self-luminous white paint which contains radium on the face and hand of an old clock.
Chisholm, Hugh, ed. (1911). "Becquerel". Encyclopædia Britannica. 3 (11th ed.). Cambridge University Press.
Chisholm, Hugh, ed. (1911). "
