title: Greece

paragraphs: Greece ( or ), officially the Hellenic Republic ( ), (historically known as Hellas) (Greek: Ελλάς), is a country in Southeastern Europe. Its capital city is Athens.

paragraphs: It borders Albania, North Macedonia and Bulgaria to the north, and Turkey to the east. The Aegean Sea is to the East and South of mainland Greece, the Ionian Sea is to the West. Both are part of the Eastern Mediterranean Sea and have many islands. 80% of the country is mountainous, with Mount Olympus being the highest peak.

paragraphs: Ancient Greece created democracy, philosophy, science and mathematics, drama and theater and the Olympic Games.

paragraphs: Greece is a parliamentary republic, in which the leader of the party with more seats in the parliament is the Prime Minister. The country has a President, but his powers are ceremonial. He is the head of state, not head of government, much like how Kings and Queens operate in constitutional monarchies and is elected by Parliament and not the people. Its economy is the highest in the Balkans region, though facing financial difficulties due to a Greek government-debt crisis.

paragraphs: The official language spoken in Greece is Greek, spoken by 99% of the population and 90% of the population identifies as Christian Orthodox. Many Greeks also understand English, French and German, which are taught in schools. Greece was a founding member of the United Nations, joined NATO in 1952, became a member of the European Union in 1981 and adopted the Euro in 2001. Due to the large tourism industry, powerful shipping sector and its geostrategic importance, it is classified as a middle power.

paragraphs: Greece's history is one of the richest in the world. The Greeks were one of the most advanced civilizations. Greece is famous for its many philosophers, like Plato and Aristotle, and kings like Alexander the Great and Leonidas. Greece is said to be the "birthplace of Democracy", because city-states like Athens, now the capital of Greece, were the first to elect their leaders and not have kings. During the years of Alexander the Great, a huge Macedonian empire was created that stretched from modern-day Greece to Egypt and Iran, until the borders of India. Because of the significant role that Greek culture played during that time, it is called the Hellenistic period (or "Greek-dominated period"). During that time, the Greek language became the 'lingua franca' of the Middle East, which means the language that people who do not speak the same language use to communicate, like English is used today as an international language.

paragraphs: Greece was then ruled by the Roman Empire, and many argue that Rome conquered Greece with its army, but Greece conquered Rome with its culture. The Roman Empire after the conquest of Greece became a civilization known as the Greco-Roman (or Greek-Roman) civilization. When the Roman Empire collapsed, the Greeks emerged as the ruling class of the Byzantine Empire, and the Greek language became the official language of the empire, which included all the territories around the eastern Mediterranean Sea. It was then occupied by the Ottoman Empire for a period of 400 years. Some areas of Greece, like the second-largest city in the country, Thessaloniki, were occupied for 500 years and became part of Greece in the early 20th century.

paragraphs: The Greek War of Independence began in 1821 and Greece was an independent country (a republic) in 1828. In 1832 Greece was made a kingdom by the United Kingdom and Russia, under the German Wittelsbach dynasty.

paragraphs: In 1912, Greece took part in the Balkan Wars, where it gained many of the territories that make up the country now, such as Greek Macedonia and the islands of the Aegean Sea. Greece fought in both World War I and World War II in the side of allies. During World War I, Greece was divided into two countries, the State of Thessaloniki in the north and the State of Athens in the south. Both countries claimed to be the legitimate government of Greece, but the State of Thessaloniki received support from the Allies. The country was reunited in 1917, when the King abdicated. In 1920 Greece expanded again, and briefly reached its maximum size. The territories that the country had gained in Turkey were given back to Turkey in the 1923 Treaty of Lausanne, but Greece kept Western Thrace. The king returned in 1935, and Greece was under a fascist dictatorship from 1936 until 1941, friendly to the Allies, when it was invaded by Nazi Germany.

paragraphs: In 1940, Greece was invaded by Italy, but defeated the invasion. This was the first victory of an Allied country against an Axis power. After this, Hitler decided to attack Greece sooner than he had planned. Germany invaded on 6 April 1940 and captured Greece's second-largest city of Thessaloniki on 9 April, while Athens was captured on 27 April. Most fighting ended with the Battle of Crete. Greece suffered major damages in the war.

paragraphs: Between 1946 and 1949, the Greeks fought a civil war. The fighting was between the communists and the people who supported the king, who also had support from the United Kingdom and the United States. The war left the country devastated and the people very poor.

paragraphs: In 1967 the military took control of the country and restricted democracy. Free elections were then held again 7 years later, and the Greeks voted to send the king away and declared a republic in 1974. Greece became a member of the European Union in 1981. Greece had seen rapid growth in the 1990s, but some of the country's economic statistics were modified to appear more correct than they were, as the government had lied with the help of banks from the United States. In 2004, Greece hosted the Olympic Games for a second time. Since 2009, Greece has been in an economic crisis, which is also becoming a political crisis.

paragraphs: Greece is not a federal state like the United States, but a unitary state like the United Kingdom. It is ruled by a parliament, called the "Hellenic Parliament" (or "Greek Parliament" in Simple English), which has 300 members. It is a parliamentary republic, which means that, unlike in the United States, the President has very few powers. The person in charge of the government of Greece is the Prime Minister.

paragraphs: Greece was a kingdom for most of its history as an independent nation. It officially became the "Third Hellenic Republic" (or "Third Republic of Greece" in Simple English) in 1975, when the monarchy was abolished by a popular vote.

paragraphs: Greece was under a military dictatorship between 1966 and 1975. Demonstrations by the students of the universities across Greece took place in 1973, but were suppressed by the regime, which forcibly stopped the protests. The dictatorship collapsed after the invasion of Cyprus, and handed over power to Constantine Karamanlis.

paragraphs: There are many political parties in Greece, but only seven are in the Greek parliament. Until 2015, only two political parties formed governments, the PASOK party (which is social democratic) and New Democracy (ND, which is conservative). The government ousted in the 2015 election was led by PASOK, DIMAR AND ND. Other parties include the Communist party, the left-wing SYRIZA party, the nationalist party and others. SYRIZA, led by Alexis Tsipras, won the 2015 parliamentary election held on January 25 of that year, and entered into a coalition government with the small right-wing party "Greek Independents".

paragraphs: The divisions of Greece are called 'Peripheries'. As of January 2011, there are 13 peripheries in Greece. Peripheries are subdivided into 'peripheral units', and previously they were known as 'prefecture', but prefectures were abolished in 2011. The most populated peripheries in Greece are Attica, where the capital city of Greece, Athens, is, and Central Macedonia, where Greece's second-largest city, Thessaloniki, is. All the peripheries, and their capital cities, are:

paragraphs: Greece is a small country compared to other countries such as the United States, Spain , Italy, and the United Kingdom. The population of Greece is estimated to be over 10 million. Most of the people in Greece are Greeks, and they form 94% of the population of the country. There are also many Albanians in Greece, and they make up 4% of the population. Other nationalities make up for another 2% of the country.

paragraphs: The Greek government recognizes only one minority in the country, the Turkish one in the region of Thrace. The dispute between Greece and the Republic of Macedonia has resulted in the refusal of Greece to acknowledge the existence of a Macedonian minority. The 2001 population census showed only 747 citizens of the Republic of Macedonia in Greece. The Republic of Macedonia says that there are a maximum of 300,000 ethnic Macedonians in Greece, but Greece says that if there is a minority in the country, it would not be more than 30,000 people, in the northern part of the country, near the border with the Republic of Macedonia. This is also supported by international organizations.

paragraphs: The Greek flag was officially adopted in 1828 as a civil and state ensign (a flag for use only on boats and ships) and as a national flag when flown outside of Greece, for example on embassies. A different flag (white cross on a blue field) was used as a land flag within Greece from 1828 until 1969 and from 1975 to 1978. In 1978 the current flag became national flag and the older land flag was abolished.

paragraphs: There are many theories about the origin of the color of the flag. One says that the blue represents the color of the sea and the white represents the waves, and others include white for the waves and blue for the sky and white for purity and breakaway from tyranny and blue for Greece. There are nine stripes on the flag, which according to the legend represent the nine syllables in the phrase “Ελευθερία ή Θάνατος’’ which means “freedom or death.’’ The cross stands for Christianity.

paragraphs: Greece is a capitalist country, like the United States and France. Greece has the largest number of trading ships (a 'merchant navy') in the world. Tourism is also a major source of income for Greece. In the 20th century Greece had its own currency but now uses the Euro as most other European Community countries do.

paragraphs: Greece has adopted some welfare state policies, such as public healthcare and free education, like many other European countries. Greece, however, has not collected enough taxes to pay for them. The pension system is especially expensive.

paragraphs: This is putting Greece in a very difficult situation when the country has accumulated a debt of about €350 billion, or debt by 170 per-cent of the country's total GDP. Greece also has a trade deficit, meaning that it buys more things than it sells. The country is cutting costs and asking for loans in order to avoid bankruptcy.

paragraphs: About 30 million tourists visit Greece each year. That is more than the country’s entire population. To serve the many tourists, Greece has many international airports. Tourism also makes up more than 20% of the Greek GDP.


title: Sweden

paragraphs: Sweden () is a Nordic country in the part of Europe called Scandinavia. Its neighbors are Finland and Norway. Sweden is also connected to Denmark in the south by a bridge. It is a developed country. It is famous for its welfare state. People who live in Sweden are called Swedes.

paragraphs: The population of Sweden is about 10,12 million people. Sweden's capital city is Stockholm, which is also Sweden's largest city, with almost one million people. Other large cities are Gothenburg and Malmö. These cities are all in the southern half of the country, where it is not as cold as in the north. Swedes drink filmjölk, it is a traditional fermented milk product from Sweden, It is made by fermenting cow's milk, Glogg, is Spiced mulled wine. It normally contains red wine, sugar, orange peel, and spices. Swedes eat yellow pea soup with pork (or pork sausages) along with mustard.

paragraphs: Sweden is a constitutional monarchy because it has a king, Carl XVI Gustaf, but he does not have any real power. Sweden is a parliamentary state meaning that the government is elected by the parliament which is appointed by the people. The country is democratically ruled by a government headed by an elected prime minister. Stefan Löfven was elected Prime Minister in September 2014. He took office in October 2014.

paragraphs: Sweden has an official majority language, Swedish (the Swedish word for the language is "svenska"). Sweden has five official minority languages: Finnish, Yiddish, Sami, Meänkieli, and Romani.

paragraphs: Sweden became a member of the European Union (EU) on 1 January 1995. Unlike most countries in the European Union, Sweden is not a member of the Eurozone and has not begun to use the euro as currency. This is because the people have voted against using the euro. The currency remains the Swedish krona (Swedish crown).

paragraphs: Sweden has been a country for a thousand years. In the Middle Ages Sweden had the same king as Denmark and Norway. In the early 16th century Sweden got its own king, Gustav Vasa. During the 17th century Sweden was a great power. Sweden had taken Estonia, Latvia, and Finland and parts of Norway, Germany, and Russia. In the 18th century Sweden became weaker and lost these places. In the early 19th century Sweden's king died without an heir and the Swedish parliament voted for Jean Baptiste Bernadotte as the new king. Bernadotte fought Denmark and made them allow Norway to enter a personal union with Sweden.

paragraphs: This was Sweden's last war, and Sweden has not been at war for 200 years. In 1905, the Swedish-Norwegian personal union was dissolved. In many wars, including World War I and the Cold War, the country was neutral, meaning it did not take sides. During World War II, it traded with both the British and the Germans in order to protect its neutrality.

paragraphs: Sweden is divided into 21 counties. They are Stockholm, Uppsala, Södermanland, Östergötland, Jönköping, Kronoberg, Kalmar, Gotland, Blekinge, Skåne, Halland, Västra Götaland, Värmland, Örebro, Västmanland, Dalarna, Gävleborg, Västernorrland, Jämtland, Västerbotten, and Norrbotten.

paragraphs: Sweden has 25 historical provinces ("landskap"). They are found in three different regions: Norrland in the North, Svealand in the central region, and Götaland in the South.

paragraphs: Sweden has been Christian for a thousand years. Sweden is traditionally a Protestant country, but it is now one of the least religious countries in the world. Statistical surveys say 46-85% of all people in Sweden are agnostics or atheists. This means they do not believe in a god. About 6.4 million people in Sweden, which is 67% of all the people, are members of the Church of Sweden, but only 2% of members go to church often.

paragraphs: In popular music, ABBA, Roxette, The Cardigans, Europe, Entombed, At the Gates, In Flames, Dark Tranquillity, Hypocrisy, Grave, Dissection, Avicii, Tove Lo, Laleh, Watain, and Ace of Base have had several hits throughout the years.

paragraphs: Sweden is a country with many talented athletes, such as soccer player Zlatan Ibrahimović. Sweden (men and women's teams combined) has five bronze medals and two silver medals from the World Cup in football (soccer). The soccer league in Sweden is called Allsvenskan (men's) and Damallsvenskan (women's). Sweden has also performed well in ice hockey. The men's ice hockey top division in Sweden is called SHL and the women's SDHL. Sweden has also had several successful table tennis players, including Stellan Bengtsson and Jan-Ove Waldner, as well as alpine skiers including Ingemar Stenmark, Pernilla Wiberg, and Anja Pärson. Other champions include biathlete Magdalena Forsberg and tennis players Björn Borg, Mats Wilander, Stefan Edberg, and Jonas Björkman. Swimmer Sara Sjöström has several gold, silver and bronze medals from the Olympic Games and holds several world records.

paragraphs: Sweden also succeeds in cross-country skiing, having won several medals in the Olympic games.


title: Albert Einstein

paragraphs: Albert Einstein (14 March 1879 – 18 April 1955) was a German-born scientist. He worked on theoretical physics. He developed the theory of relativity. He received the Nobel Prize in Physics in 1921 for theoretical physics. His famous equation is formula_1 (E = energy, m = mass, c = speed of light).

paragraphs: At the beginning of his career, Einstein did not think that Newtonian mechanics was enough to reconcile (bring together) the laws of classical mechanics and the laws of the electromagnetic field. Between 1902–1909 he developed the theory of special relativity to correct that. Einstein also thought that Isaac Newton's idea of gravity was not completely correct. So, he extended his ideas on special relativity to include gravity. In 1916 he published a paper on general relativity with his theory of gravitation.

paragraphs: In 1933, Einstein was visiting the United States. In Germany, Adolf Hitler and the Nazis came to power. Einstein, being of Jewish ethnicity, did not return to Germany due to Hitler’s anti-Semitic policies. He lived in the United States and became an American citizen in 1940. On the beginning of World War II, he sent a letter to President Franklin D. Roosevelt explaining to him that Germany was in the process of making a nuclear weapon; so Einstein recommended that the US should also make one. This led to the Manhattan Project, and the US became the first nation in history to create and use the atomic bomb (not on Germany though but Japan). Einstein and other physicists like Richard Feynman who worked on the Manhattan project later regretted that the bomb was used on Japan.

paragraphs: Einstein lived in Princeton and was one of the first members invited to the Institute for Advanced Study, where he worked for the remainder of his life. He is widely considered one of the greatest scientists of all time. His contributions helped lay the foundations for all modern branches of physics, including quantum mechanics and relativity.

paragraphs: Einstein was born in Ulm, Württemberg, Germany, on 14 March 1879. His family was Jewish, but was not very . However, later in life Einstein became very interested in his Judaism. Einstein did not begin speaking until he was 2 years old. According to his younger sister, Maja, "He had such difficulty with language that those around him feared he would never learn". When Einstein was around 4 years old, his father gave him a magnetic compass. He tried hard to understand how the needle could seem to move itself so that it always pointed north. The needle was in a closed case, so clearly nothing like wind could be pushing the needle around, and yet it moved. So in this way Einstein became interested in studying science and mathematics. His compass gave him ideas to the world of science.

paragraphs: When he became older, he went to a school in Switzerland. After he graduated, he got a job in the patent office there. While he was working there, he wrote the papers that first made him famous as a great scientist.

paragraphs: Einstein married with a 20-year-old Serbian woman Mileva Marić in January 1903.

paragraphs: In 1917, Einstein became very sick with an illness that almost killed him. His cousin Elsa Löwenthal nursed him back to health. After this happened, Einstein divorced Mileva in 14 February 1919, and married Elsa on 2 June 1919.

paragraphs: Einstein's first daughter was "Lieserl" (no one knows her real name). She was born in Novi Sad, Vojvodina, Austria-Hungary in the first months of 1902. She spent her very short life (believed to be less than 2 years) in the care of Serbian grandparents. It is believed she died from scarlet fever. Some believe she may have been born with the disorder called Down syndrome, although it never . No one knew her very existence until 1986, when Einstein's granddaughter discovered a shoe box containing 54 love letters (most of them from Einstein), exchanged between Mileva and Einstein from 1897 to September 1903.

paragraphs: Einstein's two sons were Hans Albert Einstein and Eduard Tete Einstein. Hans was born in Bern, Switzerland in May 1904 and Eduard was born in Zürich, Switzerland in July 1910. Eduard died at 55 years old of a stroke in Psychiatric University Hospital Zurich . He had spent his life in and out of asylums due to his Schizophrenia.

paragraphs: Just before the start of World War I, he moved back to Germany, and became head of a school there. He lived in Berlin until the Nazi government came to power. The Nazis hated people who were Jewish or who came from Jewish families. They Einstein of helping to create "Jewish physics," and German physicists tried to prove that his theories were wrong.

paragraphs: In 1933, under death threats from the Nazis and hated by the Nazi-controlled German press, Einstein and Elsa moved to Princeton, New Jersey in the United States, and in 1940 he became a United States citizen.

paragraphs: During World War II, Einstein and Leó Szilárd wrote to the U.S. president, Franklin D. Roosevelt, to say that the United States should invent an atomic bomb so that the Nazi government could not beat them to the punch. He was the only one who signed the letter. However, he was not part of the Manhattan Project, which was the that created the atomic bomb.

paragraphs: Einstein, a Jew but not an Israeli citizen, was offered the presidency in 1952 but turned it down, stating "I am deeply moved by the offer from our State of Israel, and at once saddened and ashamed that I cannot accept it." Ehud Olmert was reported to be considering offering the presidency to another non-Israeli, Elie Wiesel, but he was said to be "very not interested".

paragraphs: He taught physics at the Institute for Advanced Study at Princeton, New Jersey until his death on 18 April 1955 of a aortic aneurysm. He was still writing about quantum physics hours before he died.

paragraphs: He was awarded the Nobel Prize in Physics.

paragraphs: The theory of special relativity was published by Einstein in 1905, in the paper "On the Electrodynamics of Moving Bodies". It says that both distance measurements and time measurements change near the speed of light. This means that as one get closer to the speed of light (nearly 300,000 kilometres per second), lengths appear to get shorter, and clocks tick more slowly. Einstein said that special relativity is based on two ideas. The first is that the laws of physics are the same for all observers that are not moving in relation to each other.

paragraphs: Things going in the same direction at the same speed are said to be in an "inertial frame".

paragraphs: People in the same "frame" measure how long something takes to happen. Their clocks keep the same time. But in another "frame" their clocks move at a different rate. The reason this happens is as follows. No matter how an observer is moving, if he measures the speed of the light coming from that star it will always be the same number.

paragraphs: Imagine an astronaut were all alone in a different universe. It just has an astronaut and a spaceship. Is he moving? Is he standing still? Those questions do not mean anything. Why? Because when we say we are moving we mean that we can measure our distance from something else at various times. If the numbers get bigger we are moving away. If the numbers get smaller we are moving closer. To have movement you must have at least two things. An airplane can be moving at several hundred kilometers per hour, but passengers say, "I am just sitting here."

paragraphs: Suppose some people are on a spaceship and they want to make an accurate clock. At one end they put a mirror, and at the other end they put a simple machine. It shoots one short burst of light toward the mirror and then waits. The light hits the mirror and bounces back. When it hits a light detector on the machine, the machine says, "Count = 1," it simultaneously shoots another short burst of light toward the mirror, and when that light comes back the machine says, "Count = 2." They decide that a certain number of bounces will be defined as a second, and they make the machine change the seconds counter every time it has detected that number of bounces. Every time it changes the seconds counter it also flashes a light out through a porthole under the machine. So somebody outside can see the light flashing every second.

paragraphs: Every grade school child learns the formula d=rt (distance equals rate multiplied by time). We know the speed of light, and we can easily measure the distance between the machine and the mirror and multiple that to give the distance the light travels. So we have both d and r, and we can easily calculate t. The people on the spaceship compare their new "light clock" with their various wrist watches and other clocks, and they are satisfied that they can measure time well using their new light clock.

paragraphs: Now this spaceship happens to be going very fast. They see a flash from the clock on the space ship, and then they see another flash. Only the flashes do not come a second apart. They come at a slower rate. Light always goes at the same speed, d = rt. That is why the clock on the spaceship is not flashing once a second for the outside observer.

paragraphs: Special relativity also relates energy with mass, in Albert Einstein's E=mc formula.

paragraphs: E=mc, also called the mass-energy equivalence, is one of the things that Einstein is most famous for. It is a famous equation in physics and math that shows what happens when mass changes to energy or energy changes to mass. The "E" in the equation stands for energy. Energy is a number which you give to objects depending on how much they can change other things. For instance, a brick hanging over an egg can put enough energy onto the egg to break it. A feather hanging over an egg does not have enough energy to hurt the egg.

paragraphs: There are three basic forms of energy: potential energy, kinetic energy, and rest energy. Two of these forms of energy can be seen in the examples given above, and in the example of a pendulum.

paragraphs: A cannonball hangs on a rope from an iron ring. A horse pulls the cannonball to the right side. When the cannonball is released it will move back and forth as diagrammed. It would do that forever except that the movement of the rope in the ring and rubbing in other places causes friction, and the friction takes away a little energy all the time. If we ignore the losses due to friction, then the energy provided by the horse is given to the cannonball as potential energy. (It has energy because it is up high and can fall down.) As the cannonball swings down it gains more and more speed, so the nearer the bottom it gets the faster it is going and the harder it would hit you if you stood in front of it. Then it slows down as its kinetic energy is changed back into potential energy. "Kinetic energy" just means the energy something has because it is moving. "Potential energy" just means the energy something has because it is in some higher position than something else.

paragraphs: When energy moves from one form to another, the amount of energy always remains the same. It cannot be made or destroyed. This rule is called the "conservation law of energy". For example, when you throw a ball, the energy is transferred from your hand to the ball as you release it. But the energy that was in your hand, and now the energy that is in the ball, is the same number. For a long time, people thought that the conservation of energy was all there was to talk about.

paragraphs: When energy transforms into mass, the amount of energy does not remain the same. When mass transforms into energy, the amount of energy also does not remain the same. However, the amount of matter and energy remains the same. Energy turns into mass and mass turns into energy in a way that is defined by Einstein's equation, E = mc.

paragraphs: The "m" in Einstein's equation stands for mass. Mass is the amount of matter there is in some body. If you knew the number of protons and neutrons in a piece of matter such as a brick, then you could calculate its total mass as the sum of the masses of all the protons and of all the neutrons. (Electrons are so small that they are almost negligible.) Masses pull on each other, and a very large mass such as that of the Earth pulls very hard on things nearby. You would weigh much more on Jupiter than on Earth because Jupiter is so huge. You would weigh much less on the Moon because it is only about one-sixth the mass of Earth. Weight is related to the mass of the brick (or the person) and the mass of whatever is pulling it down on a spring scale – which may be smaller than the smallest moon in the solar system or larger than the Sun.

paragraphs: Mass, not weight, can be transformed into energy. Another way of expressing this idea is to say that matter can be transformed into energy. Units of mass are used to measure the amount of matter in something. The mass or the amount of matter in something determines how much energy that thing could be changed into.

paragraphs: Energy can also be transformed into mass. If you were pushing a baby buggy at a slow walk and found it easy to push, but pushed it at a fast walk and found it harder to move, then you would wonder what was wrong with the baby buggy. Then if you tried to run and found that moving the buggy at any faster speed was like pushing against a brick wall, you would be very surprised. The truth is that when something is moved then its mass is increased. Human beings ordinarily do not notice this increase in mass because at the speed humans ordinarily move the increase in mass in almost nothing.

paragraphs: As speeds get closer to the speed of light, then the changes in mass become impossible not to notice. The basic experience we all share in daily life is that the harder we push something like a car the faster we can get it going. But when something we are pushing is already going at some large part of the speed of light we find that it keeps gaining mass, so it gets harder and harder to get it going faster. It is impossible to make any mass go at the speed of light because to do so would take infinite energy.

paragraphs: Sometimes a mass will change to energy. Common examples of elements that make these changes we call radioactivity are radium and uranium. An atom of uranium can lose an "alpha particle" (the atomic nucleus of helium) and become a new element with a lighter nucleus. Then that atom will emit two electrons, but it will not be stable yet. It will emit a series of alpha particles and electrons until it finally becomes the element Pb or what we call lead. By throwing out all these particles that have mass it has made its own mass smaller. It has also produced energy.

paragraphs: In most radioactivity, the entire mass of something does not get changed to energy. In an atomic bomb, uranium is transformed into krypton and barium. There is a slight difference in the mass of the resulting krypton and barium, and the mass of the original uranium, but the energy that is released by the change is huge. One way to express this idea is to write Einstein's equation as:

paragraphs: The c in the equation stands for the speed of light squared. To square something means to multiply it by itself, so if you were to square the speed of light, it would be 299,792,458 meters per second, times 299,792,458 meters per second, which is approximately

paragraphs: So the energy produced by one kilogram would be:

paragraphs: About 60 terajoules were released by the atomic bomb that exploded over Hiroshima. So about two-thirds of a gram of the radioactive mass in that atomic bomb must have been lost (changed into energy), when the uranium changed into krypton and barium.

paragraphs: The idea of a Bose-Einstein condensate came out of a collaboration between S. N. Bose and Prof. Einstein. Einstein himself did not invent it but, instead, refined the idea and helped it become popular.

paragraphs: The concept of zero-point energy was developed in Germany by Albert Einstein and Otto Stern in 1913.

paragraphs: In classical physics, momentum is explained by the equation:

paragraphs: When Einstein generalized classical physics to include the increase of mass due to the velocity of the moving matter, he arrived at an equation that predicted energy to be made of two components. One component involves "rest mass" and the other component involves momentum, but momentum is not defined in the classical way. The equation typically has values greater than zero for both components:

paragraphs: There are two special cases of this equation.

paragraphs: A photon has no rest mass, but it has momentum. (Light reflecting from a mirror pushes the mirror with a force that can be measured.) In the case of a photon, because its m = 0, then:

paragraphs: The energy of a photon can be computed from its frequency ν or wavelength λ. These are related to each other by Planck's relation, E = hν = hc/λ, where h is the Planck constant (6.626×10 joule-seconds). Knowing either frequency or wavelength, you can compute the photon's momentum.

paragraphs: In the case of motionless particles with mass, since p = 0, then:

paragraphs: Therefore, the quantity "m" used in Einstein's equation is sometimes called the "rest mass." (The "0" reminds us that we are talking about the energy and mass when the speed is 0.) This famous "mass-energy relation" formula (usually written without the "0"s) suggests that mass has a large amount of energy, so maybe we could convert some mass to a more useful form of energy. The nuclear power industry is based on that idea.

paragraphs: Einstein said that it was not a good idea to use the classical formula relating momentum to velocity, p = mv, but that if someone wanted to do that, he would have to use a particle mass m that changes with speed:

paragraphs: In this case, we can say that E = mc is also true for moving particles.

paragraphs: The General Theory of Relativity was published in 1915, ten years after the special theory of relativity was created. Einstein's general theory of relativity uses the idea of spacetime. Spacetime is the fact that we have a four-dimensional universe, having three spatial (space) dimensions and one temporal (time) dimension. Any physical event happens at some place inside these three space dimensions, and at some moment in time. According to the general theory of relativity, any mass causes spacetime to curve, and any other mass follows these curves. Bigger mass causes more curving. This was a new way to explain gravitation (gravity).

paragraphs: General relativity explains gravitational lensing, which is light bending when it comes near a massive object. This explanation was proven correct during a solar eclipse, when the sun's bending of starlight from distant stars could be measured because of the darkness of the eclipse.

paragraphs: General relativity also set the stage for cosmology (theories of the structure of our universe at large distances and over long times). Einstein thought that the universe may curve a little bit in both space and time, so that the universe always had existed and always will exist, and so that if an object moved through the universe without bumping into anything, it would return to its starting place, from the other direction, after a very long time. He even changed his equations to include a "cosmological constant," in order to allow a mathematical model of an unchanging universe. The general theory of relativity also allows the universe to spread out (grow larger and less dense) forever, and most scientists think that astronomy has proved that this is what happens. When Einstein realized that good models of the universe were possible even without the cosmological constant, he called his use of the cosmological constant his "biggest blunder," and that constant is often left out of the theory. However, many scientists now believe that the cosmological constant is needed to fit in all that we now know about the universe.

paragraphs: A popular theory of cosmology is called the Big Bang. According to the Big Bang theory, the universe was formed 15 billion years ago, in what is called a "gravitational singularity". This singularity was small, dense, and very hot. According to this theory, all of the matter that we know today came out of this point.

paragraphs: Einstein himself did not have the idea of a "black hole", but later scientists used this name for an object in the universe that bends spacetime so much that not even light can escape it. They think that these ultra-dense objects are formed when giant stars, at least three times the size of our sun, die. This event can follow what is called a supernova. The formation of black holes may be a major source of gravitational waves, so the search for proof of gravitational waves has become an important scientific pursuit.

paragraphs: Many scientists only care about their work, but Einstein also spoke and wrote often about politics and world peace. He liked the ideas of socialism and of having only one government for the whole world. He also worked for Zionism, the effort to try to create the new country of Israel.

paragraphs: Einstein's family was Jewish, but Einstein never practiced this religion seriously. He liked the ideas of the Jewish philosopher Baruch Spinoza and also thought that Buddhism was a good religion.

paragraphs: Even though Einstein thought of many ideas that helped scientists understand the world much better, he disagreed with some scientific theories that other scientists liked. The theory of quantum mechanics discusses things that can happen only with certain probabilities, which cannot be predicted with better precision no matter how much information we might have. This theoretical pursuit is different from statistical mechanics, in which Einstein did important work. Einstein did not like the part of quantum theory that denied anything more than the probability that something would be found to be true of something when it was actually measured; he thought that it should be possible to predict anything, if we had the correct theory and enough information. He once said, "I do not believe that God plays dice with the Universe."

paragraphs: Because Einstein helped science so much, his name is now used for several different things. A unit used in photochemistry was named for him. It is equal to Avogadro's number multiplied by the energy of one photon of light. The chemical element Einsteinium is named after the scientist as well. In slang, we sometimes call a very smart person an "Einstein."

paragraphs: Most scientists think that Einstein's theories of special and general relativity work very well, and they use those ideas and formulas in their own work. Einstein disagreed that phenomena in quantum mechanics can happen out of pure chance. He believed that all natural phenomena have explanations that do not include pure chance. He spent much of his later life trying to find a "unified field theory" that would include his general relativity theory, Maxwell's theory of electromagnetism, and perhaps a better quantum theory. Most scientists do not think that he succeeded in that attempt.


title: Euro

paragraphs: Euro is the currency (money) of the countries in the eurozone. One euro is divided into 100 "cent" (officially) (singular) or "cents" (unofficially).

paragraphs: Because of the number of different languages in the European Union, there are different, unofficial, names for this unit (the French call them "centimes" and the Spanish "céntimos", for example).

paragraphs: It was created in 1999, but until 1 January 2002 it was used only for electronic payments. In 2002, 12 countries of the European Union (EU) took their state currencies out of circulation and adopted euro notes and coins as their only money. There was a change-over period, called the ""transition period"", when both the old national money and the euro were accepted, but by 28 February 2002, all 12 countries were using just euros.

paragraphs: In 2006, Slovenia became the 13th country to use the euro. In 2008 Cyprus and Malta became the 14th and 15th countries to use the euro. In 2009, Slovakia became the 16th country to use the euro. In 2011, Estonia became the 17th country to use the euro. In 2014, Latvia became the 18th country and in 2015, Lithuania became the 19th country to use the euro.

paragraphs: There are seven different banknotes, each one with a different colour, size and face value: €5 (grey), €10 (red), €20 (blue), €50 (orange), €100 (green), €200 (yellow), €500 (purple).

paragraphs: Coins are of eight different amounts: €0.01, €0.02, €0.05, €0.1, €0.2, €0.5, €1, €2.

paragraphs: On every banknote, there is a picture of a different European building style. All banknotes are the same throughout the entire eurozone; there are no different designs for different countries, unlike the euro coins. One side of each coin is the same in all euro countries. The other side is different since each country who mints the coins inserts a symbol relating to that country. Today there are many different sets of coins. Any of the coins can be used everywhere throughout the eurozone despite the country-specific symbol on the back.

paragraphs: The ten new European countries that entered the European Union in May 2004 are planning to adopt the Euro also. First they must meet some conditions to show that they have stable economies.

paragraphs: The symbol for the euro is the Greek letter epsilon (E) with two horizontal lines: €.

paragraphs: Some people see it as the Latin capital letter C with an equal sign (=).

paragraphs: It is also legal to simply write "euro". This is especially useful when the symbol cannot be produced, or the result is not satisfactory.

paragraphs: These countries form the Economic and Monetary Union (EMU).

paragraphs: Even though they are not part of the EU, the euro is also the currency used in:

paragraphs: Many other countries' currencies are "pegged" (tied) to, although not exactly equal to, the euro:


title: Currency

paragraphs: Currency is the unit of money used by the people of a country or Union for buying and selling goods and services.

paragraphs: Certain currencies are said to be "pegged" or "fixed" to something, usually another currency. A fixed or pegged currency is one that has a constant value compared to what it is pegged to. For example, the Cape Verdian escudo is pegged to the Euro. If the value of the Euro goes up 1% compared to another form of currency, the value of the escudo also goes up 1% compared to that same currency.

paragraphs: Many countries have used systems where their currency was pegged to a commodity rather than to another currency. Most used either gold or silver. When they did this, as the value of gold increased, so did the value of their money. This was called the "gold standard" or "silver standard". Most countries stopped using silver and gold standards in the 20th century.

paragraphs: This list appears in alphabetical order:


Mercure


title: Radio telescope

paragraphs: A radio telescope is a type of antenna, like a huge satellite television dish. It is used for radio astronomy. Stars shine and the light can be seen with an ordinary telescope, but they also give off radio waves. Scientists with radio telescopes receive these radio waves and use computers to learn about the stars. Other things like black holes also give off radio waves and radio telescopes are useful for learning about them too.

paragraphs: The dish is sometimes constructed of a conductive wire mesh whose openings are smaller than a wavelength. The information received by several radio telescopes in different places can be combined. This gives similar results to having a single dish as big as the distance between the telescopes. It can receive very faint signals, and see more details. The biggest telescope is a virtual radio telescope almost as big as the Earth, called the Event Horizon Telescope.

paragraphs: The radio telescope at the Parkes Observatory, Parkes, New South Wales was used by NASA to receive messages from the Apollo 11 moon landings.


title: Light year

paragraphs: A light year (symbol: ly) is the distance that light travels in empty space in one year. Since the speed of light is about 300,000 km per second (about 186,000 miles per second), then a light year is about 10 trillion kilometers (about 6 trillion miles). A light year is not a length of time.

paragraphs: The light year is used in astronomy because the universe is huge. Space objects such as stars and galaxies may be hundreds, thousands or millions of light years away.

paragraphs: Think of a star at a distance of 100 light years from us on Earth. Light leaves the star and takes 100 years to get to us. When we see the star's light, we are seeing that star as it was 100 years ago.


title: Korea

paragraphs: Korea is a peninsula in northeast Asia. It covers a peninsula called the "Korean Peninsula". Korea became a country (or state) in 918. In 1948, it split into two countries: North Korea and South Korea. North and South Korea and their allies fought against each other in the Korean War.

paragraphs: People have lived in Korea for about 15,000 years. In the past, some of modern Manchuria and Siberia was governed by Korea. Korea is known for its fine silk. In the 7th century, the people of China sought after gold-workers from Korea. Europeans had little knowledge about Korea until the modern era.

paragraphs: Korea is famous for its traditional food kimchi. The Korean people usually eat sticky white rice. Traditionally, Koreans eat seaweed soup on their birthdays. People believe the soup is also good for pregnant women.

paragraphs: South Korea has over 50 million people, and North Korea has more than 23 million. South Korea's biggest city is Seoul, the capital of South Korea. The city has more than 10 million people and the region of Seoul has more than 15 million people. North Korea's biggest city is Pyongyang, the capital of North Korea. It has fewer than 4 million people.

paragraphs: Korean people speak Korean. Many people in South Korea study English and other languages(Chinese, Japanese, ...) in school.

paragraphs: South Korea is an advanced country with large cities, high-speed rail trains, high-speed internet, and many television and radio networks. Many Korean television dramas are popular around the world. But there are still poor areas, even in South Korea. The Korean farmers are not rich and struggle to compete with cheap food from other countries.

paragraphs: Gojoseon is the first state in Korean history. It was established in 2333 BCE. Its real name is Joseon, but it is called Gochosun to make it different from other Joseon in Korean history. "Go" is a Korean prefix meaning 'old'. The founder of Gojoseon is said to be Dangun. The Korean people believe that Dangun established the country on October 3rd, and still celebrate that day. In Korea, October 3rd is a national holiday, which is named Gaecheonjeol (The day heaven opened). It is said to be the day that Dangun's father whose name is Hwan-ung came from the sky on October 3rd 2457 BCE. Gochosun was destroyed by the Chinese Han Dynasty in 108 BCE.

paragraphs: After Gojoseon had been destroyed, there were many confederations in the Korean Peninsula and Manchuria: "Mahan, Byeonhan, Jinhan, Buyeo, Dongye, Okjeo, Goguryeo", and so on. The ancient confederation countries later merged into three more powerful kingdoms and an advanced confederation country.

paragraphs: Between 57 BC and the year 668 there were three kingdoms in the Korean Peninsula and Manchuria. The names of the kingdoms were: "Silla", "Goguryeo" and "Baekje". In the year 372, the religion Buddhism came from China to Korea. Buddhism was very important in Korea.

paragraphs: In the year 660, the kingdom of Silla invaded the kingdom of Baekje. In the year 668 the kingdom of Silla invaded the kingdom of Goguryeo. The people of Goguryeo ran away and made a new kingdom with the name "Barhae". After a little time, the kingdom of Balhae was invaded by Liao Dynasty.

paragraphs: When Silla was the only country, it had the name "Unified Silla". In the Silla kingdom Buddhism was very important.

paragraphs: In the year 698, Balhae was founded by allies of Goguryeo. We call the time when united Silla and Balhae were existing together (698∼926) "The northern and southern kingdoms period".

paragraphs: In the year 918 the kingdom of "Goryeo" began. The name "Korea" comes from "Goryeo". The kingdom of Goryeo had power until the year 1392.

paragraphs: The kingdom of Goryeo wrote the law in books, and had a big government. Buddhism was very important in the kingdom of Goryeo. Bronze-type printing technology was invented in Goryeo Dynasty. This is known as the world's oldest bronze-type printing technology.

paragraphs: In the year 1392 a man from the military of Korea went to China. His name was "Yi Seonggye". Yi's job was to attack China. But Yi returned without doing it. When Yi came back to Korea, he changed the kingdom. Yi became king.

paragraphs: The name of the kingdom was "Joseon". In the year 1394, the people of Joseon moved the capital to Seoul. The religion of Buddhism was not important. A new religion, Confucianism was important. Confucianism came from China.

paragraphs: In the year 1443 the king "Sejong" ruled. He invented the Korean alphabet Hangeul.

paragraphs: In the year 1592 and the year 1598 the people from Japan fought Korea. A man from the military made very strong ships, including the famous "turtle ship". The name of the man was "Yi Sun-sin". With the strong ships, the people of Korea won.

paragraphs: The people of Joseon were friends with the people of China.

paragraphs: Today, North Koreans use the name Joseon (officially Chosŏn) to mean Korea.

paragraphs: In the 19th century the people of Korea did not want to trade with other people. People called Korea "Hermit Kingdom".

paragraphs: The people of the United States and Japan wanted to trade with Korea. Before 1876, people failed when they tried to use force to trade with Korea. In the year 1876 the military of Japan fought Korea. Korea and Japan made a contract to trade.

paragraphs: In 1895 Japan won the First Sino-Japanese War in the Korean peninsula. This ended Chinese influence in Korea. Empress Myeongseong, also called Queen Min, wanted the Russian Empire as a friend, to help Korea against Japan. Agents of the Ambassador of Japan killed her in October 1895.

paragraphs: In 1905 Japan won the Russo-Japanese War. In the year 1910, the emperor of Japan made Korea a colony of Japan.

paragraphs: Korea was occupied by Japan from 1910 to 1945.

paragraphs: When World War II started, the policy of the Japanese government changed. The government made the religion of Japan (Shinto) the religion of Korea.

paragraphs: In 1945 Japan lost World War II. The United States and Soviet Union made a contract. United States occupied the south of Korea and Soviet Union occupied the north of Korea.

paragraphs: The people of Korea wanted to be independent. The United States and the Soviet Union agreed the people of Korea would be free and independent. But soon the United States and Soviet Union were not friends and the Cold War started. United States and Soviet Union refused to settle a deal. In 1948 the people in the south made an independent country called South Korea (also called the Republic of Korea). The United States helped them. In 1948 the people in the north also made a country North Korea (also called the DPRK or Democratic People's Republic of Korea). The Soviet Union helped North Korea.

paragraphs: In 1950 a war started in Korea. The name of the war was the Korean War. The war ended in 1953, but no peace treaty was signed. The border line between North and South was almost the same in the end as it was before the war.


title: English as a second language

paragraphs: English as a second language is a common phrase which has related acronyms, including

paragraphs: Each of these acronyms means roughly the same thing. In each, the learners already have another native or "mother" language, and they want to learn English as well.

paragraphs: The teaching of English as a second language has a long history. For example, the official introduction of English into India's education system began in 1835.

paragraphs: English as a second language is the single most popular subject in the world, after mathematics. English is a very important language in business. Many people study English as a foreign language, because they want a better job. English is also very important in education. Many pages on the internet are in English.

paragraphs: Many people who can not go to English language classes study on the internet, using websites like BBC Learning English.

paragraphs: Many people study English in a country where the people speak English. This way, many students learn to listen and speak English better.

paragraphs: There are many English exams. These English exams are important for learners. They may show how well a person can use English. It is very difficult to compare different English exams. Every exam is a little different. Read Testing English as a foreign language for more information.

paragraphs: Global Scale of English (GSE) is a test for learners of English as a second or foreign language. The GSE is a list of can-do statements based on the Common European Framework of Reference (CEFR) for English. Learners' abilities are rated on a 10-to-90 point scale for each of the four basic skills (speaking, listening, reading, and writing). A learner reaches a level on the scale when she or he can correctly perform 50% of the can-do tasks at that level. The education company Pearson PLC developed the scale.

paragraphs: Teaching English as a foreign language (TEFL) is referred to the practice of teaching the English language to the students with different first languages. It is taught in the state school system or privately with a language school or with a tutor. TEFL can also take place in an English-speaking country for people who have immigrated there.

paragraphs: TEFL teachers may be native or non-native speakers of English. Other forms of TEFL are TESL ("Teaching English as a second language"), TESOL ("Teaching English to speakers of other languages"), and ESL ("English as a second language").


title: Switzerland

paragraphs: Switzerland (; ; ; ; Swiss German: "Schwiz") is a comparatively small country in Western Europe. The official name of Switzerland is "Confoederatio Helvetica". This is Latin and is not often used except for state documents. Switzerland is a confederation of even smaller states, which are the 26 cantons.

paragraphs: Switzerland is known for its neutrality. A country is neutral when it does not take sides among the countries who are at war. Switzerland has been neutral since 1815. Many international organizations are in Switzerland. The United Nations has a main office (but not its headquarters) in Geneva. Its predecessor organization, the League of Nations, was headquartered in Geneva.

paragraphs: There are four official languages in Switzerland: German, French, Italian, and Romansh. Some cantons and even towns have two languages spoken in them, and the largest canton by area, Graubünden, has three. About 2/3 of the population speak German; French is spoken in the west of the country, while Italian is spoken in the canton of Ticino and Romansh in parts of Graubünden. Romansh language is spoken less than by 1% of the population.

paragraphs: The capital of Switzerland is Bern. The largest city of Switzerland is Zürich.

paragraphs: To the north of Switzerland is Germany. East of Switzerland are Austria and Liechtenstein. To the south of Switzerland is Italy. To the west of Switzerland is France.

paragraphs: The area of Switzerland is 41,285 km². The confederation is divided into 23 full states called "cantons". All 26 cantons are: Aargau, Appenzell Innerrhoden, Appenzell Ausserrhoden, Basel-Stadt, Basel-Land, Berne, Fribourg, Geneva, Glarus, Graubünden, Jura, Lucerne, Neuchâtel, Nidwalden, Obwalden, Schaffhausen, Schwyz, Solothurn, St. Gallen, Thurgau, Ticino, Uri, Valais, Vaud, Zug, and Zürich.

paragraphs: The mountains are very tall in the center and south of Switzerland. About 60% of Switzerland is in the Alps area. Only few people live here. The highest mountain is the "Dufour Peak" at 4,634 m.

paragraphs: Many of the mountains have ice all year. This ice is called glaciers. The rivers Rhine, Rhône, and many other rivers start in the mountains of Switzerland.

paragraphs: There are many lakes in Switzerland. The biggest lakes are all in the north and west: Lake Geneva ("Lac Léman"), Lake Zürich, Lake Neuchâtel and Lake Constance ("Bodensee").

paragraphs: Mountains in the north of Switzerland are fewer and smaller. That is why most Swiss people live in cities and towns in the north. The Jura mountains are in the northwest of Switzerland.

paragraphs: Switzerland has 2,485 villages, towns and cities.

paragraphs: There are about 8.4 million people in Switzerland. About 64% of the people speak Swiss German (German Alemannic) as their first language, in northern and central Switzerland. 19% of the people speak French as their first language, mainly in the west of Switzerland. 8% of the people speak Italian, in the south of Switzerland. Only 1% of the people speak Romansh, in the southeastern part of Switzerland. Romansh is an old language that is similar to Latin.

paragraphs: The German-speaking people of Switzerland do not actually speak "German" as their native language. Swiss people speak something called Alemannic which has its own writing language and grammar but still is normally considered a German dialect. Alemannic may be difficult for Germans to understand. Swiss people do write like the people from Germany and also speak standard German very well, especially in the larger cities.

paragraphs: About 23% of the people in Switzerland do not come from Switzerland. They come from other places to usually work in Switzerland.

paragraphs: The religion of most people in Switzerland is Christianity. 43% of the population follow Catholicism. 35% of the population follow Protestantism. 2% follow Eastern Orthodoxy. The religion of 4% of the population is Islam. The rest follow other religions, or they have no religion.

paragraphs: Switzerland is famous for its chocolate, cheese, banking system, watches and mountains.

paragraphs: In 1291, people from Uri, Schwyz and Unterwalden wanted to be free. They signed a contract to work together called the "Eternal Alliance". Together, they could be free from the people of Habsburg, who were very strong. In 1315 the people from the Eternal Alliance fought the Habsburgs in battles at Morgarten, Sempach and Näfels. The people of the Eternal Alliance won all the battles.

paragraphs: People from other areas signed the contract and joined the Eternal Alliance. More and more people worked together to be free. In 1648, other countries from Europe made an agreement that Switzerland was free. The name of this agreement was the "Peace of Westphalia". More areas came to be part of Switzerland.

paragraphs: In 1798, France invaded Switzerland. The ruler of France was Napoleon. He changed many laws. In 1815 Switzerland again became independent from France. Other countries agreed at the Congress of Vienna that Switzerland was free and neutral.

paragraphs: The constitution of Switzerland that was made after a short civil war in 1848 was replaced in 1999. Switzerland did not fight in World War I or World War II. Since 2002, Switzerland is part of the United Nations. It did not join the United Nations for 57 years because of its neutrality.

paragraphs: Switzerland is a republic. Switzerland does not have the same kind of president as the United States or France. Seven people (called ministers) do the job of president. They are called the Federal Council in English, "Bundesrat" in German, "Conseil Fédéral" in French, "Consiglio Federale" in Italian and "Cussegl Federal" in Romansh. Every year one of these people is made president. The president is not more important than the other six people. At present 3 of the 7 people are women.

paragraphs: There are two parts of parliament in Switzerland. The "Council of States" and the "National Council". Only both together can make laws. There are 46 people in the Council of States. Every full canton of Switzerland can send 2 people. There are 200 people in the National Council. The biggest canton sends most people to the National Council. The smallest 6 cantons can only send one person to the National Council.

paragraphs: The people of Switzerland can collect signatures if they do not like a new law or a law change. This is called a "referendum". If enough people sign a referendum, the people vote. The people can also collect signatures to change the constitution. This is called an "initiative". The constitution is the basic law of a country.

paragraphs: Switzerland is not a member of the European Union, but it is member of the European Free Trade Agreement (EFTA). The EFTA makes trade with other countries in Europe easier. In 1999 Switzerland and the European Union made a contract. This contract makes trade even easier. They recently made two other contracts.

paragraphs: The banks of Switzerland and the insurance companies in Switzerland together produce eleven per cent of the gross domestic product. Tourism is important in Switzerland. There are many places for tourists. Davos, St. Moritz, Pontresina and Flims are in Switzerland. These towns are important both in winter (for skiing) and in summer. Tourists also like the cities of Lucerne, Geneva, and Zürich.

paragraphs: In 2011 the pharmaceutical industry in Switzerland directly and indirectly employed about 135,000 people. The companies Novartis and Roche are the second and third largest pharma companies in the world. They both have invented many life saving drugs because of well developed research and development facilities.

paragraphs: The literature of Switzerland is divided according to the language used. Most Swiss literature was written in German from 1291 until 1798. French became popular in Bern and elsewhere in the 18th century and many words also in the German speaking parts of Switzerland come from the French and are not known to Germans. Italian language and Romansch-Latin literature are less common in Switzerland.

paragraphs: Heidi, a book for children by Johanna Spyri, is the most famous book of Switzerland. It is in the mountains in Graubünden.

paragraphs: Skiing, snowboarding and mountaineering are among the most popular sports in Switzerland. Because of the large mountain range the nature of the country is well suited for such activities. Bobsleigh was invented in St. Moritz. The first world ski championships were held in Mürren (1931) and St. Moritz (1934). St. Moritz hosted the second Winter Olympic Games in 1928 and in 1948. Among the most successful skiers and world champions are Pirmin Zurbriggen and Didier Cuche.

paragraphs: Many Swiss are fans of football. The national team or 'Nati' is widely supported. Switzerland was the joint host, with Austria, of the Euro 2008 tournament. Many Swiss also follow ice hockey. In April 2009, Switzerland hosted the 2009 IIHF World Championship for the 10th time. The National League A is the most attended league in Europe.

paragraphs: The many lakes in the country make Switzerland a good place for sailing. The largest, Lake Geneva, is the home of the sailing team Alinghi. They were the first European team to win the America's Cup in 2003. They also won in 2007. Tennis has become more popular. Swiss players such as Martina Hingis and Roger Federer have won multiple Grand Slams.

paragraphs: Motorsport racecourses and events were banned in Switzerland after the 1955 Le Mans disaster. There were exceptions for events such as Hillclimbing. This ban was overturned in June 2007. During this period, the country still had successful racing drivers such as Clay Regazzoni, Sebastian Buemi, Jo Siffert and successful World Touring Car Championship driver Alain Menu. Switzerland also won the A1GP World Cup of Motorsport in 2007–08 with driver Neel Jani. Swiss motorcycle racer Thomas Lüthi won the 2005 MotoGP World Championship in the 125cc category.

paragraphs: Traditional sports include Swiss wrestling or "Schwingen". It is an old tradition from the rural central cantons and considered the national sport by some. Hornussen is another native Swiss sport. It is like a cross between baseball and golf. Steinstossen is the Swiss version of stone put, a competition in throwing a heavy stone. It is recorded to have taken place in Basel in the 13th century. It is also central to the Unspunnenfest, first held in 1805.


title: LOL

paragraphs: LOL, or lol, is an internet slang term that means "laugh(ing) out loud". It is commonly mistaken for "lots of love." LOL is often used in messages meaning "That is really funny."

paragraphs: It also means mute in Persian and is a native Dutch word (not an acronym) which means "fun" ("lollig" means "funny"). In Welsh, lol means nonsense - e.g., if a person wanted to say "utter nonsense" in Welsh, they would say "rwtsh lol". LOL is usually used on the internet or when text messaging.


title: Toronto

paragraphs: Toronto is the capital city of the province of Ontario in Canada. It is also the largest city in both Ontario and Canada. Found It is on the north-west side of Lake Ontario.

paragraphs: The City of Toronto has a population of over 3 million people. Even more people live in the regions around it. All together, the Greater Toronto Area is home to over 6 million people. That makes it the biggest metropolitan area in Canada.

paragraphs: Toronto was created in 1793 by John Graves Simcoe as the capital of what was then called ""Upper Canada"". At the time it was called the "Town of York" after the Duke of York. The name was changed to Toronto in 1834. With the Canadian Confederation in 1867, it became the capital of the newly created province of Ontario. Toronto was one of two cities (along with Montreal in Quebec) that wanted to be the capital of Canada. Queen Victoria decided that Ottawa should be the national capital because it was located between the two.

paragraphs: As the 19th century moved on, the city began to grow. This was mainly because of immigration, where people from all over the world left their home and moved to Canada. Many of the immigrants were Irish people. They brought their Catholic faith with them when they left Ireland because of the Irish Potato Famine.

paragraphs: During World War I and World War II, Toronto was used to train members of the Canadian Army. After the wars, even more immigrants came to the city. The population was becoming so big that the Government of Ontario decided to create Metropolitan Toronto in 1954, combining a number of local municipalities. These were Old Toronto, York, East York, North York, Etobicoke, and Scarborough.

paragraphs: By 1981, Toronto had more people than Montreal even though it was created after Montreal. Because of that, the Ontario government decided to make Toronto a "megacity" in 1998. The first mayor of Toronto was Mel Lastman. As Toronto moved into the 21st century, it became host to a number of worldwide events. These included World Youth Day in 2002, WorldPride in 2014, and the 2015 Pan American Games.

paragraphs: On April 23, 2018 a white van collided with numerous pedestrians killing nine and injuring sixteen others at Yonge Street.

paragraphs: Toronto has a hot-summer humid continental climate (Köppen climate classification "Dfa").

paragraphs: Toronto has a humid continental climate ("Dfa" in the Köppen climate classification). This is because although the city is next to Lake Ontario, the lake is not big enough to keep its temperature mild.

paragraphs: As the biggest city in Canada and one of the biggest in all of North America, Toronto is a popular destination for tourists. It is where you can find the CN Tower, which is the tallest free-standing (not supported) structure in the Americas and one of the Seven Wonders of the Modern World. There are some other buildings, including the City Hall and the Rogers Centre, that are well known for their design style. There are many skyscrapers, because many large banks of Canada and other companies have their main offices in Toronto, and the Toronto Stock Exchange which is the biggest stock market in Canada.

paragraphs: Because Toronto is the capital of Ontario, it is where the provincial government meets. Visitors can see how the province is run by visiting the legislature in Queen's Park. There are museums, including the Royal Ontario Museum, the Art Gallery of Ontario, the Ontario Science Centre, the Hockey Hall of Fame, and the headquarters of the Canadian Broadcasting Corporation. In the suburbs of the city is the Toronto Zoo and Canada's Wonderland. Many visitors also like to go to Niagara Falls, just an hour's drive away from Toronto.

paragraphs: Toronto is full of places to visit, eat, shop, and enjoy. In the downtown area are shopping centres, including the Eaton Centre, St. Lawrence Market, and the Distillery District. There are several theatres, many which are run by the Mirvish family. The Four Seasons Centre for the Performing Arts, opened in June 2006, is home to the Canadian Opera Company and the National Ballet of Canada. Across the harbor are the Toronto Islands, the best known of which is Centre Island.

paragraphs: Toronto has many sports teams. Some of them belong to the most commonly-followed leagues in North America. They include the Toronto Maple Leafs in ice hockey (NHL) and the Toronto Raptors in basketball (NBA), both of which play in the Air Canada Centre. The nearby Rogers Centre is where the Toronto Blue Jays baseball team plays. BMO Field in Exhibition Place is home to the Toronto Argonauts in Canadian football and Toronto F.C., a soccer club.

paragraphs: Toronto is a very multicultural city. Different people from around the world have moved to Toronto to live since the 20th century. There is a Chinatown, Little Italy, Little Tokyo, Greektown, Little Portugal, and other places where different cultures are kept alive. These people hold festivals where they share their culture with others. Among the most popular is the Canadian National Exhibition (CNE), which happens every year in August.

paragraphs: Like many cities around the world, Toronto has an airport, Toronto Pearson International Airport. There are flights to many places in Canada and the rest of the world. The airport is just northwest of the city centre. Since 2015, there has been a train service, the Union Pearson Express. It goes from the airport to Downtown in less than half an hour.

paragraphs: Toronto's main public transportation system is operated by the Toronto Transit Commission (TTC). The main part of its public transport network is the Toronto subway system. That system includes three heavy-rail rapid transit lines spanning the city, including the U-shaped Line 1 and east–west Line 2. A light metro line also exists, exclusively serving the eastern district of Scarborough. A discussion is underway to replace it with a heavy-rail line. The TTC also operates an extensive network of buses and streetcars. The streetcars serve the downtown core. The buses provide service to many parts of the city not served by the sparse subway network.

paragraphs: The Government of Ontario also operates a commuter rail and bus transit system called GO Transit in the Greater Toronto Area. GO Transit carries over 250,000 passengers every weekday (2013) and 57 million annually. Most of them travel to or from Union Station. GO Transit is implementing RER (Regional Express Rail) into its system.

paragraphs: Housing in Toronto was ranked as 10th-least affordable in the world. The study compared Toronto with ninety other metropolitan areas in different countries. Hong Kong came in as the least affordable place to live in.


title: Names of numbers in English

paragraphs: Here are some words for small numbers. Words in bold are irregular.

paragraphs: When writing other numbers between 21 and 99, you must use a hyphen (-).

paragraphs: The number 100 is written as "one hundred", but sometimes people say "a hundred".

paragraphs: The way numbers are written and spoken differs between American English and other forms of English, such as British English and Australian English, as follows.

paragraphs: To write a whole number from 100 to 999 in American English:

paragraphs: In standard, written, American English, the word "and" is "not" in the word-name of any whole number even though many speakers insert it.

paragraphs: To write a whole number from 100 to 999 in British and Commonwealth English:

paragraphs: In standard, written, British English (and the English spoken in many other places), the word "and" "is" in the word-name of many whole numbers.


title: United States dollar

paragraphs: The United States dollar, or the American dollar, is the official currency, or money, of the United States of America and is also used in a number of . It is also the standard currency for international markets selling goods such as gold and oil (petrol). When writing, the symbol for the American dollar is the dollar sign ($). Dollars can also be known as USD (U.S. Dollar).

paragraphs: The American one dollar bill has a picture of George Washington. There are currently paper bills (currency) of 1, 2, 5, 10, 20, 50, and 100 dollars.

paragraphs: All U.S. dollar currency has been the same size since 1928, unlike some countries where bank notes, or pieces of paper money, with different values have different sizes.

paragraphs: The U.S. also has dollar coins. Some are silver colored and some are gold colored. Vending machines often give dollar coins as change, since it is easier for the machines to give out coins than paper money. Some of the more advanced vending machines give out paper money as change. Paper dollars are much more common than dollar coins.

paragraphs: The US dollar in subdivided into cents, and 100 cents equals 1 US dollar. One cent can be written as either $0.01 or 1¢. The cent or "penny" (not to be confused with the English penny sterling) is the least worth coin used in the U.S.. There are several different coins with different cent values of different materials and sizes. There is the penny (1¢ or $0.01), nickel (5¢ or $0.05), dime (10¢ or $0.10), quarter (25¢ or $0.25), and the much rarer half-dollar (50¢ or $0.50). All coins and paper bills have the faces of famous Americans on the front side.

paragraphs: The paper "dollar bill" is actually called a "Federal Reserve Note". Federal Reserve notes are legal tender currency notes. The twelve Federal Reserve Banks issue them into circulation pursuant to the Federal Reserve Act of 1913. A commercial bank belonging to the Federal Reserve System can obtain Federal Reserve notes from the Federal Reserve Bank in its district whenever it wishes by paying for them in full, dollar for dollar, from its account with Federal Reserve Bank.

paragraphs: Federal Reserve Banks obtain the notes from the U.S. Bureau of Engraving and Printing (BEP). It pays the BEP for the cost of producing the notes, which then become liabilities of the Federal Reserve Banks, and obligations of the United States Government.

paragraphs: Congress has specified that a Federal Reserve Bank must hold collateral equal in value to the Federal Reserve notes that the Bank receives. This collateral is chiefly gold certificates and United States securities. This provides backing for the note issue. The idea was that if the Congress dissolved the Federal Reserve System, the United States would take over the notes (liabilities). This would meet the requirements of Section 411, but the government would also take over the assets, which would be of equal value. Federal Reserve notes represent a first lien on all the assets of the Federal Reserve Banks, and on the collateral specifically held against them.

paragraphs: Federal Reserve notes are not redeemable in gold, silver or any other commodity, and receive no backing by anything. This has been the case since 1933. The notes have no value for themselves, but for what they will buy. In another sense, because they are legal tender, Federal Reserve notes are "backed" by all the goods and services in the economy.

paragraphs: The Coinage Act of 1965, specifically Section 31 U.S.C. 5103, entitled "Legal tender," which states: "United States coins and currency (including Federal reserve notes and circulating notes of Federal reserve banks and national banks) are legal tender for all debts, public charges, taxes, and dues."

paragraphs: This statute means that all United States money as identified above are a valid and legal offer of payment for debts when tendered to a creditor. There is, however, no Federal statute mandating that a private business, a person or an organization must accept currency or coins as payment for goods and/or services. Private businesses are free to develop their own policies on whether or not to accept cash unless there is a State law which says otherwise. For example, a bus line may prohibit payment of fares in pennies or dollar bills. In addition, movie theaters, convenience stores and gas stations may refuse to accept large denomination currency (usually notes above $20) as a matter of policy.

paragraphs: The public typically obtains its cash from banks by withdrawing cash from automated teller machines (ATMs) or by cashing checks. The amount of cash that the public holds varies seasonally, by the day of the month, and even by the day of the week. For example, people demand a large amount of cash for shopping and vacations during the year-end holiday season. Also, people typically withdraw cash at ATMs over the weekend, so there is more cash in circulation on Monday than on Friday.

paragraphs: To meet the demands of their customers, banks get cash from Federal Reserve Banks. Most medium- and large-sized banks maintain reserve accounts at one of the 12 regional Federal Reserve Banks, and they pay for the cash they get from the Fed by having those accounts debited. Some smaller banks maintain their required reserves at larger, "correspondent," banks. The smaller banks get cash through the correspondent banks, which charge a fee for the service. The larger banks get currency from the Fed and pass it on to the smaller banks.

paragraphs: When the public's demand for cash declines—after the holiday season, for example—banks find they have more cash than they need and they deposit the excess at the Fed. Because banks pay the Fed for cash by having their reserve accounts debited, the level of reserves in the nation's banking system drops when the public's demand for cash rises; similarly, the level rises again when the public's demand for cash subsides and banks ship cash back to the Fed. The Fed offsets variations in the public's demand for cash that could introduce volatility into credit markets by implementing open market operations.

paragraphs: The popularization of the ATM in recent years has increased the public's demand for currency and, in turn, the amount of currency that banks order from the Fed. Interestingly, the advent of the ATM has led some banks to request used, fit bills, rather than new bills, because the used bills often work better in the ATMs.

paragraphs: Each of the 12 Federal Reserve Banks keeps an inventory of cash on hand to meet the needs of the depository institutions in its District. Extended custodial inventory sites in several continents promote the use of U.S. currency internationally, improve the collection of information on currency flows, and help local banks meet the public's demand for U.S. currency. Additions to that supply come directly from the two divisions of the Treasury Department that produce the cash: the Bureau of Engraving and Printing, which prints currency, and the United States Mint, which makes coins. Most of the inventory consists of deposits by banks that had more cash than they needed to serve their customers and deposited the excess at the Fed to help meet their reserve requirements.

paragraphs: When a Federal Reserve Bank receives a cash deposit from a bank, it checks the individual notes to determine whether they are fit for future circulation. About one-third of the notes that the Fed receives are not fit, and the Fed destroys them. As shown in the table below, the life of a note varies according to its denomination. For example, a $1 bill, which gets the greatest use, remains in circulation an average of 5.9 years; a $100 bill lasts about 15 years. Federal Reserve Bank of New York on Sunday night Cole


title: Fluid ounce

paragraphs: A fluid ounce is a unit of volume in both the imperial system of units and the U.S. customary units system. However, the two measures are not quite the same:


title: Shape of the universe

paragraphs: The shape of the Universe cannot be discussed with everyday terms, because all the terms need to be those of Einsteinian relativity. The geometry of the universe is therefore not the ordinary Euclidean geometry of our everyday lives.

paragraphs: According to the special theory of relativity, it is impossible to say whether two distinct events occur at the same time if those events are separated in space. To speak of "the shape of the universe (at a point in time)" is naive from the point of view of special relativity. Due to the relativity of simultaneity we cannot speak of different points in space as being "at the same point in time" nor, therefore, of "the shape of the universe at a point in time".

paragraphs: What astrophysicists do is ask whether a particular model of the universe is consistent with what is known through observations and measurements of the universe. If the observable universe is smaller than the entire universe (in some models it is many orders of magnitude smaller or even infinitesimal), observation is limited to a part of the whole.

paragraphs: Consideration of the shape of the universe can be split into two:<br>

paragraphs: The observable universe is the basis for testing any model of the universe. It is a spherical volume (a ball) centered on the observer, regardless of the shape of the universe as a whole. Every location in the universe has its own observable universe, which may or may not overlap with the one centered on Earth.

paragraphs: Recent measurements have led NASA to state, "We now know that the universe is flat with only a 0.4% margin of error". Within one model, the FLRW model, the present most popular shape of the Universe found to fit observational data is the infinite flat model. There are other models that also fit the data.


title: Meteor shower

paragraphs: A meteor shower is an event when many meteors seem to come from one point in the night sky. These meteors are caused by meteoroids entering Earth's atmosphere at extremely high speeds on parallel paths. Most meteors are smaller than a grain of sand, so almost all of them burn up and never hit the Earth's surface.

paragraphs: A meteor shower is the result of an interaction between a planet, such as Earth, and streams of debris from a comet. Comets are dirty snowballs, made up of rock embedded in ice, orbiting the Sun. Each time a comet swings by the Sun in its orbit, some of its ice vaporizes and meteoroids will be shed. The meteoroids spread out along the entire orbit of the comet to form a meteoroid stream, also known as a "dust trail".

paragraphs: Most of our short-period meteor showers are the product of rare disintegrations, when large chunks break off a mostly dormant comet. Examples are the Quadrantids and Geminids. They originated from a breakup of asteroid-like objects, 2003 EH1 and 3200 Phaethon, respectively, about 500 and 1000 years ago. The fragments tend to fall apart quickly into dust, sand, and pebbles, and spread out along the orbit of the comet to form a dense meteoroid stream, which later moves into Earth's path.

paragraphs: The most visible meteor shower in most years are the Perseids, which peak on 12 August each year at over one meteor per minute. NASA has a useful tool to calculate how many meteors per hour are visible from your observing location.

paragraphs: The Leonid meteor shower peaks around 17 November of each year. About every 33 years, the Leonid shower produces a big meteor storm, peaking at thousands of meteors per hour. Leonid storms gave birth to the term "meteor shower" when it was first realised, during the November 1833 storm, that the meteors radiated from near the star Gamma Leonis. The last Leonid storms were in 1999, 2001 (two), and 2002 (two). Before that, there were storms in 1767, 1799, 1833, 1866, 1867, and 1966. When the Leonid shower is not "storming" it is less active than the Perseids.