AcharyaChanakya/simple-wikipedia huggingface dataset:
Like Adam and Eve on the ceiling, all the figures were shown naked. Some of the cardinals in the church said that it was wicked to paint saints, including the Virgin Mary, with no clothes on. They called Michelangelo "the painter of rude bits". There was a long argument about this because some people said that God had created everyone naked, so clothes would not be needed in Heaven. After Michelangelo's death another artist, Daniele da Volterra was called in to paint drapes on the figures. For the rest of his life, he was known as "the painter of pants".
In 1546, when Michelangelo was in his seventies, he was given one of his most important jobs. The old St. Peter's Basilica had been partly demolished and a new one designed by Bramante. But many architects had worked on it and it was still just at the beginning stages. Michelangelo was made the architect. He immediately improved the plan, had important parts made much stronger, and designed a huge dome, taller than any other domes in the world. He died before it was completed, but he left drawings and models so that the next architect, Giacomo della Porta, could finish what he had started. The dome of St. Peter's Basilica still stands as one of the greatest monuments of Christianity, and as a symbol of the city of Rome.
When Michelangelo died, his body was taken back to Florence and buried in the Basilica of Santa Croce (Church of the Holy Cross). On his tomb sit three mourning figures who symbolize Architecture, Painting and Sculpture.
Leonardo da Vinci (15 April 1452 – 2 May 1519) was an Italian man who lived in the time of the Renaissance. He is famous for his paintings, but he was also a scientist, mathematician, engineer, inventor, anatomist, sculptor, architect, botanist, musician, and a writer.
Leonardo wanted to know everything about nature. He wanted to know how everything worked. He was very good at studying, designing and making all sorts of interesting things.
The art historian Helen Gardner said that no-one has ever been quite like him because he was interested in so many things that he seems to have had the mind of a giant, and yet what he was like as a person is still a mystery.
Leonardo was born at Vinci which is a small town near Florence, Italy. He was trained to be an artist by the sculptor and painter Verrocchio. He spent most of his life working for rich Italian noblemen. In his last years, he lived in a beautiful home given to him by the King of France.
Two of his pictures are among the best-known paintings in the world: the "Mona Lisa" and "The Last Supper". He did many drawings. The best-known drawing is "Vitruvian Man". Leonardo was often thinking of new inventions. He kept notebooks with notes and drawings of these ideas. Most of his inventions were never made. Some of his ideas were a helicopter, a tank, a calculator, a parachute, a robot, a telephone, evolution, and solar power.
Leonardo was born on 15 April 1452, in the Tuscan hill town of Vinci, in the valley of the Arno River. His grandfather, Antonio da Vinci, wrote down the details of the birth. Leonardo's parents were not married. His father was a Notary, Ser Piero da Vinci. His mother, Caterina, was a servant. She may have been a slave from the Middle East. or from China. His father later on took custody of Leonardo and his mother remarried and had 5 more children. Leonardo's full name was "Leonardo di ser Piero da Vinci", which means "Leonardo, the son of Messer (Mister) Pierdaom Vinci".
Leonardo spent his first five years living in a farm house with his mother. Then he lived at Vinci with his father, his father's new wife Albiera, his grandparents and uncle, Francesco. When Leonardo grew up, he only wrote down two memories from his childhood. He remembered that when he was lying outside in his cradle a large bird flew from the sky and hovered over him. Its tail feathers brushed his face. Leonardo's other important memory was how he found a cave while exploring in the mountains. He was terrified that some great monster might be hiding there. But he was also very excited and wanted to find out what was inside.
Leonardo started painting while he was still a boy. Giorgio Vasari wrote about Leonardo's life shortly after his death. He tells many interesting stories about how clever Leonardo was. He says that Leonardo painted a round wooden shield with a picture of snakes spitting fire. Messer Piero took his son's painting to Florence and sold it to an art dealer.
In 1466, when Leonardo was fourteen, his father took him to Florence, to be an apprentice to the artist Verrocchio.
Florence was a very exciting place for a young person who wanted to be an artist. Many famous artists had lived in Florence, starting with Cimabue and Giotto in the 1200s. Everywhere a person looked there were famous and beautiful artworks. The huge cathedral had an enormous new dome. The church of St John had doors that gleamed with gold and were said to be the most beautiful doors in the world. Another church had statues all around it by the most famous sculptors, including one by Leonardo's teacher Verrocchio.
If an artist was lucky, they would find a rich patron who would buy lots of their paintings. The richest family in Florence were the Medici. They had built themselves the finest palace in Florence, and liked buying paintings, statues and other beautiful things. They were also interested in the study of literature and philosophy. Many young artists hoped to get work from the Medici and their friends.
Verrocchio had a big workshop that was one of the busiest in Florence. Leonardo was learning to be an artist, so he had to learn drawing, painting, sculpting and model making. While he was at the workshop, he was able to learn all sorts of other useful skills: chemistry, metallurgy, metal working, plaster casting, leather working, mechanics and carpentry.
Leonardo was not the only young painter at Verrocchio's workshop. Many other painters were trained there, or often visited. Some of them later became famous: Ghirlandaio, Perugino and Botticelli. These artists were all just a few years older than Leonardo.
Giorgio Vasari tells an interesting story from this time of Leonardo's life. Verrocchio was painting a large picture of "the Baptism of Christ". He gave Leonardo the job of painting one of the angels holding Jesus' robe on the left side of the picture. Vasari said that Leonardo painted the angel so beautifully that Verrocchio put down his brush and never painted again. When the painting is examined closely it is possible to see that many other parts of the picture, such as the rocks, the brown stream and the background may have been painted by Leonardo as well. Verrocchio made a bronze statue of "David" at this time. It is believed that he used Leonardo as his model.
In about 1472, when he was twenty, Leonardo joined the Guild of St Luke, an organisation of artists and doctors of medicine. Even after his father set him up in his own workshop, Leonardo still enjoyed working at Verrocchio's workshop. Leonardo's earliest known work is a drawing in pen and ink of the Arno River valley. It has the date 5 August 1473. It is now in the Uffizi Gallery.
When Vasari writes about Leonardo, he uses words like "noble", "generous", "graceful" and "beautiful". Vasari tells us that as an adult Leonardo was a tall handsome man. He was so strong that he could bend horseshoes with his bare hands. His voice was so beautiful that it charmed everyone that heard it. Almost everyone wanted to be his friend. He loved animals, was a vegetarian and would buy birds at the market and set them free.
Very little is known about Leonardo's life and work between 1472 and 1481. He was probably busy in Florence. In 1478, he had an important commission to paint an altarpiece for the Monks of San Donato a Scopeto. The painting was to be the "Adoration of the Magi" ("The Three Wise Men"). The painting was never finished because Leonardo was sent away to Milan.
Leonardo was a very talented musician. In 1482, he made a silver lyre (a musical instrument) in the shape of a horse's head. At that time there was a new ruler in the city of Milan, in the north of Italy. Duke Ludovico il Moro was making other rulers nervous. Lorenzo Medici sent Leonardo to Milan as an ambassador. Lorenzo de' Medici wanted Leonardo to give Ludovico the lyre as a present from him. Leonardo wrote a letter to the Duke of Milan, telling him about all the clever and useful things that he could do, like making war machines. He wrote in the letter that he could "also paint". Leonardo did not know at the time that it was for painting that he would be mostly remembered. Leonardo stayed in Milan and worked for the Duke between 1482 and 1499. Part of his work was to design festivals and carnival processions. In Leonardo's note books are drawings of theatre costumes, amazing helmets and scenes that might be for the theatre.
Leonardo, like most other well-known artists of his time, had servants, young students and older assistants in his workshop. One of his young students was a boy whose name was Gian Giacomo Caprotti da Oreno. He was a handsome boy with beautiful long golden curls. He looked perfect as an artist's model for an angel. But he was such a difficult and dishonest boy that Leonardo called him "Salai" or "Salaino" which means "the little devil". Leonardo wrote in his notebook that Salai was very greedy, that he was a liar and that he had stolen things from the house at least five times. Salai stayed in Leonardo's household for thirty years as a pupil and a servant.
Leonardo's most important work for Duke Ludovico was to make a huge statue of the previous ruler, Francesco Sforza, on horseback. He started with the horse. After studying horses and drawing designs, he made a huge horse of clay. It was called the "Gran Cavallo". It was going to be cast in bronze. It was going to be the biggest bronze horse that had been made for more than a thousand years. Unfortunately, the bronze horse was never made. In 1494, Ludovico gave the bronze to be made into cannons because the French army was invading Milan. The huge clay horse was still standing when the French army invaded again in 1499. This time it was used for target practice and was completely destroyed.
While Leonardo was working for Duke Ludovico, he had two important painting commissions. One was to do an oil painting to go in a big altarpiece for the Confraternity of the Immaculate Conception. Leonardo did the painting twice. He left one with the monks in Milan, and took the other painting to France where it is now in the Louvre Museum. The paintings are both called "the Virgin of the Rocks". They show a scene of the Virgin Mary and the child Jesus in a rocky mysterious landscape. Mary and Jesus are meeting with John the Baptist. There is a story (which is not in the Bible but is part of Christian tradition) about how the baby John and the baby Jesus met on the road to Egypt. In this scene John is praying and the baby Jesus raises his hand to bless John. The paintings have a strange eerie light with soft deep shadows. In the background is a lake and mountains in the mist. No painting like this had ever been done before.
Leonardo's other important painting in Milan is even more famous. It is the "Last Supper". The painting shows the last meal shared by Jesus with his disciples, before his capture and death. Leonardo chose to paint the moment when Jesus has said "one of you will betray me". Leonardo tells the story of the surprise and upset that this caused to the twelve followers of Jesus. He tells the story through the actions and faces of the people in the painting. Some of them are talking, some of them have stood up, some are raising their hands in horror.
The novelist Matteo Bandello saw Leonardo at work. Bandello wrote that on some days he would paint from morning till night without stopping to eat. Then for three or four days he would not paint at all. He would often just stand and look at the painting. Vasari said that the prior of the convent was very annoyed. He asked Ludovico to tell Leonardo to work faster. Vasari said that Leonardo was worried because he did not think that he could paint the face of Jesus well enough. Leonardo told the Duke that he might use the face of the prior as his model for Judas, the traitor.
When it was finished, everyone that saw it said that the painting was a masterpiece. But Leonardo had not used proper fresco for the painting. He had used tempera over gesso, which is not usually used for wall painting. Soon the painting started to grow mold and flake off the wall. In a hundred years it was "completely ruined".
Even though in some places the paint has fallen right off the wall, the painting is so popular that it is printed and copied more that any other religious painting in the world.
In 1499, Ludovico il Moro was overthrown. Leonardo left Milan with his servant Salai and a friend, Luca Pacioli, who was a mathematician. They went to Venice. Leonardo worked as a military architect and engineer. Because Venice is a city on many islands, Leonardo tried to think of ways to defend the city from a naval attack.
In 1500, Leonardo went back to Florence, taking his "household" of servants and apprentices with him. The monks from the monastery of "The Holy Annunciation" gave Leonardo a home and a large workshop. In 2005, some buildings which were used by the Department of Military Geography were being restored. The restorers discovered that part of the building was Leonardo's studio.
Leonardo started work on a new painting. He drew a large "cartoon". (This means a drawing that is a plan for the painting.) The cartoon showed the Virgin Mary sitting on the knee of her mother, St Anne. Mary holds the baby Jesus in her arms. Jesus stretches out his hands to his young cousin John the Baptist. Vasari says that everyone was so amazed by the beautiful drawing that "men and women, young and old" came in large groups to see it "as if they were attending a great festival". The drawing is now in the National Gallery, London. Even though it is old and faded and is kept in a dark room, people go to the gallery to sit in front of it every day. Like many of Leonardo's projects, the painting was never done.
In 1502 and 1503, Leonardo worked for Cesare Borgia, a powerful noble who was the son of Pope Alexander VI. Leonardo travelled around Italy with Borgia, as a military architect and engineer. Late in 1503, Leonardo returned to Florence. He rejoined the Guild of St Luke.
He was given a very important commission. The Signoria (Town Council) of the City of Florence wanted two large frescos painted on the walls of the most important room of the Signoria Palace. Michelangelo was to paint "The Battle of Cascina" and Leonardo was to paint "The Battle of Anghiari". Leonardo began the project by studying and drawing the faces of angry men and fighting horses. These drawings can still be seen in his notebooks. But unfortunately, this was to be another failure for Leonardo. When he painted the picture on the wall, instead of using fresco, he mixed the paints with oil. The paint would not dry. Leonardo lit some fires to dry it, and the painting melted. Peter Paul Rubens drew a copy of the middle part. After a time, the town council covered it up and got somebody else to paint the wall. Michelangelo did not finish his painting either, because the Pope called him to Rome.
In about 1503 Leonardo began painting the portrait of a woman known as "Mona Lisa", the most famous portrait that has ever been painted. He continued working on it for many years. It is a small picture, painted in oil on a wooden panel. It shows the face, upper body and hands of a woman. She is very plainly dressed. For a portrait, a woman would usually put on her best clothes and jewellery. Mona Lisa has a dark dress and a fine black veil over her head. Leonardo often left symbols in his paintings that give clues about the person. The unusual thing about this picture is the smile. The smile is the clue to her name: Mona Lisa Giacondo. Giacondo means "the joking one". (Mona is short for Madonna which means "My Lady".)
The reason why the painting is so famous is that it seems to be full of mystery. Mona Lisa's eyes look out at the viewer. But no-one can guess what she is thinking. Her eyes and her mouth seem to be smiling. This is very unusual in a portrait painting. Most people in portraits look very serious. It is hard to tell what Mona Lisa's exact expression is. When a person wants to read another person's feelings, they look at the corners of their mouth and eyes. But Leonardo has painted soft shadows in the corners of Mona Lisa's mouth and eyes, to disguise her expression. The soft shadows are also found on the sides of her face, her neck and hands. The way that Leonardo uses shadow is called "sfumato" (which is an Italian word for "smoke"). Vasari said that the picture was so beautifully painted that every other artist who looked at it thought that they could never paint so well.
In 1506, Leonardo went back to Milan with his pupils, and lived in his own house in Porta Orientale. D'Oggione made several copies of the "Last Supper". Luini made a copy of "the Virgin of the Rocks". Boltraffio (and the others) painted many Madonna and Child pictures which can still be seen in art galleries and churches. One of pupils was a young nobleman called Count Francesco Melzi. Melzi never became a very good painter, but he loved Leonardo and stayed with him until the day he died.
In September 1513 Leonardo went to Rome and lived there until 1516. He lived in the Vatican. The three greatest painters of the High Renaissance, Leonardo, Michelangelo and Raphael were all working in Rome at the same time. Even though their names are often said together as if they were friends, they were not. Leonardo at this time was in his sixties, Michelangelo was middle-aged. He was not friendly to either Leonardo or Raphael. Raphael was a very clever young painter who learnt a lot by looking at the pictures painted by Leonardo and Michelangelo. But neither of them was ever his teacher.
In October 1515, King Francis I of France captured Milan. On December 19, there was a meeting of Francis I and Pope Leo X, in Bologna. Leonardo went to the meeting with Pope Leo.
Leonardo made an amazing toy to entertain King Francis. It was a life-sized mechanical lion that could walk. It had doors in its chest which opened, and a bunch of lilies came out. Lilies were the royal symbol of the French Kings.
In 1516, Francis I invited Leonardo to go to France with him. He gave Leonardo a beautiful house called "Clos Lucé" (sometimes called "Cloux"). It is near the king's palace, Chateau Amboise. Leonardo spent the last three years of his life at Clos Lucé, with his faithful friend and apprentice, Count Melzi. The king gave Leonardo a pension of 10,000 scudi. One of the last paintings that Leonardo did was a picture of "John the Baptist". His model was Salai, with his beautiful long curling hair.
When Leonardo was dying, he asked for a priest to come, so that he could make his confession and receive Holy Communion.
Leonardo died at Clos Lucé, on May 2, 1519. King Francis had become a close friend. Vasari says that the King held Leonardo's head in his arms as he died. In his will, he asked that sixty beggars should follow his casket in procession. He was buried in the Chapel of the Chateau Amboise.
Leonardo had never married and had no children of his own. In his will, he left his money, his books and most of his paintings to Count Melzi. Leonardo also remembered his other pupil Salai and his servant Battista di Vilussis, who each received half of Leonardo's vineyards near Milan. Leonardo's left to his serving woman a black cloak with a fur edge. Salai was the owner of Leonardo's most famous oil painting, the "Mona Lisa". He still owned it a few years later when he died, after fighting in a duel.
King Francis said: "There had never been another man born in the world who knew as much as Leonardo, not so much about painting, sculpture and architecture, as that he was a very great philosopher."
Leonardo did not paint very many pictures. But he drew hundreds of quick sketches, plans, maps and detailed drawings. This is the way that he recorded all the interesting things that he saw, studied and thought about.
Some of Leonardo's drawings are "studies" for paintings. In these drawings Leonardo planned the things he was going to paint. Some studies are plans for whole paintings. One of these paintings is the large beautiful drawing of the Madonna and Child with St Anne and St John the Baptist that is now in the National Gallery, London.
Many of the studies show "details" that Leonardo wanted to get just right. One study shows a very detailed perspective drawing of the ruined buildings in the background of the painting of the Magi. Other studies show hands, faces, drapery, plants, horses and babies.
The earliest drawing by Leonardo that has a date on it, is a "Landscape of the Arno Valley", 1473, which shows the river, the mountains, Montelupo Castle and the farmlands beyond it in great detail.
Leonardo studied things all his life. He did not go to university to study. He studied by looking at things in the world around him. He looked at things to see how they were made and how they worked. He drew the things that he saw and the discoveries that he made into his notebooks, and made notes about them. Many of his notebooks are now in museums. There are 13,000 pages of notes and drawings. Many of these are scientific studies.
Leonardo's notebooks are hard to read because he wrote backwards in "mirror writing". Some people think that perhaps he was trying to keep his work secret. This is not true. Leonardo wrote (and sometimes drew) with his left hand. In those days pens were made from a quill (a large feather) that was cut with a pen-knife on the end. It is hard for a left-handed person to write with a quill in the ordinary way, but quite easy to write backwards.
It is likely that Leonardo planned to publish the studies in his notebooks. He organized many pages carefully, with one study taking up the front and back of each page. There is a page with drawings and writing about the human heart and a page about the womb and the fetus. One page shows drawings of the muscles of a shoulder and another page shows how an arm works.
The notebooks were not published in Leonardo's lifetime. After he died, they were divided between different people who had known him. They are nearly all in museums or libraries such as Windsor Castle, the Louvre, and the British Library. The Biblioteca Ambrosiana (a library) in Milan has the twelve-volume "Codex Atlanticus".
Some of the things that Leonardo studied are:
Many of the drawings and notes in Leonardo's notebooks are designs, plans and inventions.
Some of the things that Leonardo designed are:
1902 (MCMII) was a common year starting on Wednesday in the Gregorian calendar.
Platinum is a soft, heavy, white metal. It is a precious metal. It usually costs more than gold.
In chemistry, platinum is element number 78, and its atoms have an atomic weight of 195 a.m.u.. The symbol for platinum is Pt, from Spanish "platina" meaning "little silver".
Platinum is very malleable and ductile, which means it can be hammered into thin sheets and it can be pulled into wire. Platinum is very stable. Acids do not affect platinum.
The most common use of Platinum is in a vehicle's catalytic converter.
List of rock types
Sorted by name; initial letter means Igneous, Sedimentary or Metamorphic rocks.
List of minerals
This is a list of minerals.
Minerals are substances that are formed naturally in the Earth. Rocks are made of minerals.
Minerals are usually solid, inorganic, have a crystal structure, and form naturally by geological processes.
The study of minerals is called mineralogy.
A mineral can be made of single chemical element or more usually a compound. There are over 4,000 types of known minerals. Two common minerals are quartz and feldspar.
A mineral is a substance that usually
One recent definition is:
Alternatively, a mineral is one listed as such by the International Mineralogical Association.
Minerals are different from rocks. A mineral is a chemical compound with a given composition and a defined crystal structure. A rock is a mixture of one or several minerals, in varying proportions.
A rock has only two of the characteristics minerals have–it is a solid and it forms naturally. A rock usually contains two or more types of minerals. Two samples of the same type of rock may have different kinds of minerals in them. Minerals are always made up of the same materials in nearly the same proportions. A ruby is a mineral. Therefore, a ruby found in India has similar makeup as a ruby found in Australia.
Minerals are formed by natural processes. A few substances with the same chemical composition as minerals can be produced by living creatures as part of their shells or bones. The shells of molluscs are composed of either calcite or aragonite, or both.
Traditionally, chemicals produced by living things are not considered minerals. However, it is difficult to see why an organic substance should not be called a mineral if its chemical nature "and" its crystalline structure is identical with its inorganic twin. This issue is now under debate: see Railsback part II.
Minerals form in many ways. The mineral halite, which is used as table salt, forms when water evaporates in a hot, shallow part of the ocean, leaving behind the salt it contained. Many types of minerals are made when molten rock, or magma cools and turns into a solid. Talc, a mineral that can be used to make baby powder, forms deep in Earth as high pressure and temperature causes changes in solid rock.
The extraordinary thing is, that most minerals owe their formation to life, or at least to the Great Oxygenation Event. "Sturdy minerals rather than fragile organic remains may provide the most robust and lasting signs of biology".
A mineral is a solid—that is, it has a definite volume and a rough shape. Volume refers to the amount of space an object takes up. For example, a golf ball has a smaller volume than a baseball, and a baseball has a smaller volume than a basketball.
A substance that is a liquid or a gas is not a mineral. However, in some cases its solid form is a mineral. For instance, liquid water is not a mineral, but ice is.
These properties are used most often:
The particles of ice that make up frost have smooth, flat surfaces. These flat surfaces form because of the arrangement of atoms in the ice, which is a mineral. Such an internal arrangement is a characteristic of minerals. It is the structure of a crystal, a solid in which the atoms are arranged in an orderly, repeating three-dimensional pattern.
Each mineral has its own type of crystal structure. In some cases, two minerals have the same chemical composition but different crystal structures. For example, both diamond and graphite consist of just one element—carbon. But the arrangements of the carbon atoms in these two minerals are not the same, so they have different crystal structures and very different properties. Diamonds are extremely hard and have a brilliant sparkle. Graphite is soft, gray, and dull.
In nature, a perfect crystal is rare. Most crystals have imperfect shapes because their growth was limited by other crystals forming next to them.
Each mineral has a definite chemical makeup: it consists of a specific combination of atoms of certain elements. An element is a substance that contains only one type of atom.
Scientists can classify minerals into groups on the basis of their chemical makeup. Though there are thousands of different minerals, only about 30 are common in Earth's crust. These 30 minerals make up most rocks in the crust. For that reason, they are called rock-forming minerals.
There are many other mineral groups.
People use minerals for many everyday purposes. Every time people turn on a microwave oven or a TV, minerals are being used. The copper in the wires that carry electricity to the machine is made from a mineral. Table salt or halite, is another mineral that people use in their everyday life.
Craft or handicraft is about making things with one's own hands and skills. The different types of crafts can be put in groups according to the material being used. In the Middle Ages the most common materials were metal, wood or clay.
A craftsman is a person who has the knowledge and skills of a craft. When they have a lot of experience they may be called a "master craftsman". If they are young people learning a craft they are called an "apprentice".
Kim Jong-il
Kim Jong-il, birth name Yuri Irsenovich Kim (according to the Soviet Union's records) (, 16 February 1941 – 17 December 2011) was the Supreme Leader of Democratic People's Republic of Korea (North Korea) from the time of his father's death in 1994 until his own death in 2011. He was the son of Kim Il-Sŏng. Official North Korean propaganda said that Jong-il was born on Mount Paektu (a holy mountain in Korea); but most historians think that he was born near Chabarowsk in the Soviet Union. The North Korean laws made him permanent ruler of North Korea for life. He was sometimes referred to as the "Dear Leader", but this was not an official title. His official title was "Chairman of the National Defense Commission of North Korea", "Supreme Commander of the Korean People's Army" and "General Secretary of the Workers' Party of Korea". Many people in North Korea were imprisoned or killed for speaking out against the Kim regime. Almost everyone in North Korea wore a small pin with a picture of Kim Jŏng-Il or Kim Il-Sŏng on it.
The North Korean government told people of his death through the state media on 19 December 2011. It was said that he had died two days earlier of "physical and mental over-work".
Jong-il was born Yuri Irsenovich Kim on 16 February 1941.
Jong-il was a Stalinist. He believed in the North Korean Communist philosophy of Juche (self-reliance). He was afraid to travel on aeroplanes and traveled only on trains. He was well known for his love of movies and luxury goods, especially caviar and Hennessey brand cognac, even though North Korea was one of the poorest countries in the world. Former United States Secretary of State Madeleine Albright once gave Jong-il a present of a basketball signed by Michael Jordan when he visited North Korea because Jong-il was a fan of the National Basketball Association and of Michael Jordan.
On the morning of 17 December 2011, at the age of 69 or 70, Jong-il died of a heart attack while traveling. His funeral was held on 28 December, and as a result, Kim Jong-un was then elected as the new leader of North Korea. On 13 April 2012, Kim Jong-il was made Eternal Chairman of the National Defence Commission and Eternal General Secretary of the Workers Party of Korea.
Silver (symbol Ag) is a chemical element. In chemistry, silver is element 47, a transition metal. It has an atomic weight of 107.86 a.m.u. Its symbol is Ag, from the Latin word for silver, "argentum".
Silver is a soft metal. It is also a precious metal. When it is used in money or in jewellery, it is often mixed with gold or some other metal to make it harder. It is bluish-white. It reflects light very well. It is a very good conductor of electricity. It is considered a precious metal. Silver is very malleable, and ductile, which means it can be pulled into wire or hammered into thin sheets. Silver is one of the only words in the English language that does not rhyme with any other word. Silver coins and bars can be bought and sold at coin shops around the world.
It is not reactive. It does not dissolve in most acids. Nitric acid dissolves it, though, to make silver nitrate. It does react with strong oxidizing agents like potassium dichromate or potassium permanganate. It does not corrode easily. It only corrodes when there is hydrogen sulfide in the air. Then, it forms a black coating known as tarnish.
Silver exists in two main oxidation states: +1 and +2. The +1 is much more common. A few compounds exist in the +2 oxidation state, but they are very strong oxidizing agents. Silver compounds can be brown, black, yellow, gray, or colorless. Silver compounds are disinfectants.
Silver(I) compounds are oxidizing agents. They are more common. Most of them are very expensive.
Silver(II) compounds are powerful oxidizing agents and rare.
Silver can be found as a native metal. Silver can be found with copper, lead, or gold in rocks. The rocks are found mostly in Canada, Mexico, Peru, and the United States. Peru produces the most silver. Silver is also in chemical compounds. Acanthite is a silver ore that is a silver compound.
Silver is extracted from the earth in several ways. It is normally extracted using electrolysis.
Silver has been used for many thousands of years by people all over the world, for jewellery, as money, and many other things. It is called a white metal even though it looks grey. The word silver is also used to talk about this color or shade of grey. Silver is also used for utensils. It may be used to fill teeth in dentistry as an amalgam. Silver is used as a catalyst.
Silver compounds are disinfectants. It can kill bacteria and has other useful properties. It is used in the silver oxide battery. They are also used in photographic film. They can also be used to reduce odors in clothes. Some silver compounds are used in creams that help burns heal.
Silver has been around for thousands of years. It was normally considered second to gold in value. Romans used silver as money. The symbol Ag is from the Latin name for silver, "argentum". Silver was also used to prevent infections and decay.
Silver is not a large danger to humans. Silver compounds are toxic. They make the skin turn blue. Some can be carcinogens. Colloidal silver, a common homeopathic remedy, is not toxic in normal amounts, but it does not do much.
Silver, because it is depleting, is actually more valuable than gold. The silver saved up in the world is running out very quickly because more of it has been used each year than the amount mined in each year since 1990. Companies that use silver have benefited from speculators who sell promises to deliver silver that does not exist, keeping prices artificially low. This is called naked short selling. The amount owed is more than all the silver in the world. The price of silver could go very high when the stored silver runs out and investors start asking for their metal back, instead of taking more I.O.U.'s.
Silver is 18 US dollars per troy ounce as of June 2010.
Silver increased to 28 US dollars per troy ounce as of December 2010.
The Pope is the head of the Catholic Church. His official title is the Bishop of Rome. Politically, he is also the head of state of the Vatican City. The current Pope is Pope Francis.
Popes are elected by Cardinals of the Catholic Church. Once they are elected they hold the position until they die or resign. Usually they do not resign, though; Pope Benedict XVI is the only Pope to resign in the last 500 years. A newly elected Pope chooses a regnal name. Everyone is told this new name when the Habemus Papam is read out. The current pope (Francis) was called Jorge Bergoglio before he became a pope.
The name "Pope" comes from the Greek word "pappas", meaning "father". Catholics believe that when making statements "ex cathedra", that is official statements teaching about faith and morals, the Pope is "infallible" - which means God will not allow his followers to be misled by allowing their leader to make a wrong statement. Only two of any Pope's statements have been "ex cathedra".
Popes today travel to many countries around the world preaching. The Pope is the only person in the world who both leads the church and government. Like other bishops he wears a big hat called a mitre and holds a staff called a crosier.
Some recent Popes, and the time they were Pope:
During parts of the Middle Ages, the French kings had a lot of influence in Europe. For this reason, seven popes (and two anti-popes) lived in Avignon, rather than Rome. The Avignon Papacy was from 1309 to 1377. During that time, the popes were known for their greed and corruption. These popes were allies of France; the enemies of France were also their enemies.
The Bishops of Rome who lived in Avignon were:
Two antipopes were based in Avignon as well:
Antipopes were people that were elected by small groups who did not like the official choice.
Catherine of Siena convinced pope Gregory XI to move back to Rome. Unfortunately, he died shortly after moving. The cardinals then elected Urban VI to be the next pope. The French cardinals did not recognise this election as legitimate. They declared the papal see as vacant; which led to the Western Schism. The schism lasted until the Council of Constance in 1417. During this time, there was a pope in Rome, an Antipope in Avignon, and for some time, a second antipope. Each of the three was recognised as legitimate pope by different European powers. This led to a big split in the church as a whole. The council elected Pope Martin V as a new pope, recognised by all parties.
The San Andreas Fault is a right-moving ('dextral') strike-slip fault. It marks the boundary between the North American Plate on the east and the Pacific Plate on the west. The fault was the cause of the 1906 San Francisco earthquake. It first appeared about 20 million years ago.
The San Andreas Fault is a zone several miles wide with multiple strands. The main active strand runs both on and off-shore between Cape Mendocino and the Sea of Cortez. From Cape Mendocino, it runs offshore to Tomales Bay. Then it goes southward through Bolinas Lagoon, just west of the San Francisco Peninsula, to come onshore again at Daly City, through the hills of the Peninsula. Crystal Springs reservoir is formed by the fault itself.
In the Santa Cruz mountains, it bends slightly eastward. This is the site of the 1989 Loma Prieta Earthquake. The fault continues south through the historic mission at San Juan Bautista and through the town of Hollister (where active creep can be seen to offset sidewalks and even houses). The Transverse Ranges north of Santa Barbara are formed by compression. Strands of the fault snake under the Los Angeles Basin. From there it connects into the active spreading under the Sea of Cortez.
The San Andreas fault was discovered by Andrew Lawson in 1895, who climbed into the faulted serpentinite well where the south tower of the Golden Gate Bridge was being poured. In spite of the extreme deformation of the serpentinite, Lawson declared the bridge perfectly safe. The events of the 1906 San Francisco earthquake would seem to support his conclusion: the ruptured strand was not the one he observed in the footprint of the bridge.
Void (astronomy)
In astronomy, voids are the empty spaces between filaments. Both filaments and Voids are one of the largest-scale structures in the Universe. There are no or few galaxies in voids. Most voids have a diameter of 11 to 150 Mpc.
Especially large voids are the empty spaces without many superclusters.
These voids are sometimes called supervoids.
A 1994 official counting (""The structure of the Universe traced by rich clusters of galaxies."", see References) lists a total of 27 supervoids with a distance of up to 740 Mpc. Some of supervoids chosen from the list are given below.
Computer mouse
A computer mouse is an input device that is used with a computer. Moving a mouse along a flat surface can move the cursor to different items on the screen. Items can be moved or selected by pressing the mouse buttons (called clicking). Today's mice have two buttons, the left button and right button, with a scroll wheel in between the two. Today, many computer mice use wireless technology and have no wire.
There are many types of mouse. Optical mouse, wireless mouse, mechanical mouse, trackball mouse. A computer mouse is a handheld hardware input device that controls a cursor in a GUI and can move and select text, icons, files, and folders. For desktop computers, the mouse is placed on a flat surface such as a mouse pad or a desk and is placed in front of your computer. The picture to the right is an example of a desktop computer mouse with two buttons and a wheel. The mouse was originally known as the X-Y position Indicator for a display system and was invented by Douglas Engelbart in 1963 while working at Xerox PARC. However, due to Alto's lack of success, the first widely used application of the mouse was with the Apple Lisa computer.
Today this device is on virtually every computer. The primary function is to move the mouse pointer on the screen. The mouse pointer can be used for many actions on the computer. Clicking or double clicking an icon, folder, or other object will open a document or execute the program. Users can also move an icon, folder, or other object by clicking a mouse button and dragging the object with the mouse pointer. Pointing to an item on the screen means moving your mouse so the pointer appears to be touching the item. When you point to something, a small box often appears that describes the item.
In 1964 Douglas Engelbart (1925-2013), a researcher at Stanford Research Institute, wanted to find a way to make using computers easier. In those days, computers were large and expensive. Using them was very hard because everything had to be typed in on a keyboard. This command line interface is still used by some people, such as programmers, to get things done faster.
After studying and designing for a long time, Engelbart succeeded in inventing an input device which he named 'XY index'. At first, it needed two hands to use, but it was changed so that only one hand was needed to use it. This model was more like the mouse that we use today, but was made up of a big ball that the user had to roll in different directions to move the cursor.
The computer mouse began to be widely used when Xerox Palo Alto Research introduced a GUI in 1981, where the mouse was used to click things on the screen. This was also the case with the Macintosh operating system from Apple of Apple Inc when it came out in 1984, as well as Microsoft Windows. Windows became popular over the years, so over time computer mice became used with many computers.
In 1991, the company Logitech invented the wireless mouse. Unlike a normal mouse, wireless mice were connected by radio signals. Newer wireless mice use Bluetooth or WiFi to connect wireless mice to computers.
On most computers, the user can move the mouse to move the cursor in the same direction. To choose something that is on the screen, the user can move the cursor to it and "click" the left mouse button. The right button is used to open menus that are different depending on where the cursor is. The other mouse buttons can do different things, depending on the software. Most mice have two buttons to click.
Most mice also have the "scroll wheel"—a small wheel found between the two main mouse buttons. The user can move the wheel back and forth to "scroll" through things like a website or folder. "Scrolling" means moving the words or pictures up or down on the screen, so another part of the page comes into view. The wheel can also be pressed, to click it like another button.
A mouse can also be connected to and used the same way with a laptop computer, but unlike a desktop computer, one does not have to be connected to use the laptop. This is because along with the keyboard, laptops have a built-in input device called a trackpad which does the same thing as a mouse. Similarly, tablet computers have a touchscreen as an input device, but some, like the Microsoft Surface and those that use Android, also work with mice.
Metallurgy is the study of metals. Alloys (mixtures of metals) are also studied. There are two main branches of Metallurgy. They are physical and chemical metallurgy. A Metallurgist is individual who researches, manufactures and develops metal items that range from car parts to semiconductors.
Metallurgists and Metallurgical Engineers often work for consulting engineering firms; mining and manufacturing companies; and in government and universities. Many metallurgists hold a Bachelor of Engineering or similar 4- year degree.
Common Job Tasks
Chemical Metallurgy is the study of extracting and refining metals through chemical reactions. This field also commonly involves corrosion prevention and surface treatment of metals. Scientific concepts such as thermodynamics, the study of heat flow and kinetics, the study of the speed of reactions are very central to chemical metallurgy.
Metallurgists are very interested in the chemical reactions that occur with different elements. Chemical reactions are carried out on a large scale to obtain a useful product.
For example, the production of steel in a blast furnace involves turning different Iron and oxide compounds into pure Iron.
<chem>3Fe2O4 + CO ->2FeO4 + CO2 </chem>
<chem>Fe3O4 + CO -> 3FeO +CO2 </chem>
<chem>FeO + CO ->Fe + CO2
</chem>
Physical metallurgy is the science of making useful properties out of metals. This field focus on the physical property of metals and alloys such as strength and hardness. Properties of metals might be electrical, magnetic and physical in nature. These properties can be changed by alloying or heat treatment.
There are many ways to make metals. For example, large parts may be created by pouring liquid metal into a large cast in a process called casting.
Important factors in physical metallurgy include time and temperature in which the metal is made and cooled. Metals undergo different phase changes, the particular position and type of crystal structure inside the metal will determine if a metal is brittle or flexible.
Ores are rocks that have a chemical compound of a metal with oxygen, called an oxide. Separating the oxygen from the metal is called smelting. This is done with chemistry or electricity, usually at very high temperatures. This is the first step in metallurgy. A rock containing enough metal to be profitable is called "ore".
An alloy is a combination of a metal with one or more elements. The metal mixture must be a solid to be called as an alloy. A common way to combine metals into an alloy is by melting them, mixing and then allowing them to solidify by cooling at room temperature. Alloys have been known since 50,000 BCE and have been continuously studied and improved.
Common Example of alloys include:
Another part of metallurgy is making parts from metals. These parts must be made so they will not break when they are used. Metallurgists look to make metal that meets the needs of the process it will be used in. Sometimes the metal must be lightweight or low in density. Other times it must be tough (not easily broken). The metallurgist must follow directions when making the part to know what metal to use. the process of metal selection is known as the materials selection process. Metallurgists use mathematical equations to determine what are the most important physical features of the metal. Common desired characteristics include ductility, toughness, corrosion resistance, and strength. Different metals and their associated features are often graphed on Ashby plots.
A metal starts as a block, called an ingot. Metallurgists must know how to make a metal part from an ingot. Parts are made from ingots different ways. When a big hammer is used, it is called forging. To make thin metals, a metal is put between two rolls and moved, called rolling.
Making metal hot makes it easier to change the shape of a metal part. For this reason, most metal parts are made using hot metal. This is hot work.
Two metal parts can be put together with much heat. This is called welding. Iron is easy to weld.
Metallurgists use many tools to determine the characterizes of metal using a technique called metallography. One of the most useful tools is the Scanning Electron Microscope. To use an SEM a metal sample is polished and hit with electrons to produce a clear image of the metal. This permits for the metal microstructure to be seen. A microstructure is what the metal looks like when zoomed in very closely. There are many types of microstructure such as pearlite and ferrite.
Metals are sometimes pulled until they break using a tensiometer. This is the tension test. Information such as plastic and elastic deformation can be determined from these tests.
It is also common for metallurgists to use computer simulations to predict heat flow or the cost of making a particular product. Common software used in metallurgy include ABAQUS and ANSYS.
Fixed-wing aircraft