AcharyaChanakya/simple-wikipedia huggingface dataset:
At the freezing point of water (0° Celsius, 32° Fahrenheit), snow melts and becomes liquid water. Sometimes, the snow will melt very fast and become water vapor. This is called sublimation. The opposite, where water vapor becomes snow, is called deposition.
Snow is used for some winter sport activities like skiing and sledding. Sometimes people make artificial snow so they can ski. People also commonly build things out of snow for fun.
Snow can also be dangerous, as it can lower visibility and make driving very difficult. When it snows, the snow will melt a little during the daytime and freeze again at night. This makes ice which can make driving conditions very treacherous. Snow plows are used to remove snow from roads to make driving easier and safer. Also, sand or salt may be added to the road to help tires grip the road. When salt is mixed with snow, the snow will melt more easily. This is because salt water has a lower melting point than fresh water (water without salt).
A blizzard is a dangerous type of a snowstorm. A blizzard produces strong winds that keep the snow in the air, thus reducing visibility. Sometimes it produce thunder snow, which is snow with lightning and thunder.
West is one of the 4 main directions on a compass. West is normally to the left on most maps. For example: (Germany is located to the west of Poland, which is itself located to the west of Lithuania). When “The West” is used in everyday speech: it usually refers to the nations of Europe (Especially from Croatia Westward) and its daughter states in the Americas and Australasia. The sun and moon also set in the west.
List of physics topics
Air resistance
Compression --Critical angle -- Colour filter -- Concave lens -- Convex lens
Diffraction -- Density (distance)--(displacement)
Electromagnetic spectrum -- Energy --
Fluid friction -- Focus -- Force sensor -- Frequency -- Friction --
Flotation
Gamma ray -- Gravity
Inertia -- Interference
Kinetic energy
Lamp-housing -- Laser pointer -- Lens -- Longitudinal wave -- Longitudinal wave model (Crova's disc) --
Moment of inertia
Normal -- Normal force -- Newton's laws of motion
Oscilloscope - Overhead projector
Plane mirror -- Potential energy -- Prism
Rarefaction -- Ray box -- Reflection -- Refraction -- Ripple tank --
relative density refleaction of light through prism
Signal generator -- Slinky -- Slit plate -- Spring -- String theory -- Sound -- Statistical mechanics
Tension -- Translucent screen -- Transverse wave -- Transverse wave model --
Vibration -- Velocity
wave -- Wave speed -- Waveform -- Wavefront -- Wavelength --
Young's double-slit experiment
A president is the leader of a country or a company or other group. A president is usually elected by the people in that group. Voting is one way to elect a president.
The President of the United States is elected by the electoral college. Some other countries choose a president this way. In some, the Parliament does it. Some countries have direct elections to choose a president. Many countries have a monarch instead of a president and some have neither.
Companies have presidents. They are elected by the people who own part of the company. In some companies, the people who are workers for the company elect (vote for) their company president.
The president of a country is not the same thing as a prime minister. A prime minister is part of a parliament, but a president is not. In some countries, (such as the United States or France), the president has more power and responsibility than anyone else. Such a president is often called the nation's chief executive. As chief executive, the president must take an active role in all phases of government. In other countries (such as India, Israel or the Republic of Ireland), to be president is more of an honor or a symbol, and the position has no real power. This kind of president is often called "head of state".
Most countries that have a King or Queen as their monarch have no president.
The American President is restricted by the written United States Constitution, which was written to make sure that the American executive never became as powerful as in the British system. The British Prime Minister is part of both the Legislature and Executive, whereas the American President is the head of the Executive. The American governmental system shows a clear separation of powers unlike the British system.
So despite having a large nuclear arsenal, the American president can not carry out policy and introduce legislation as freely as the British prime minister.
List of colors
This is a list of all the colours.
List of lakes
A list of lakes, ordered by continent:
† = the North American Great Lakes
Galileo Galilei (15 February 1564 – 8 January 1642) was an Italian polymath. Galileo was originally going to be a doctor but became a tutor instead. He was a professor of mathematics and natural science in Padua and Pisa. People most remembered him today for his conflict with the Catholic Church of his day, which led to his trial for heresy by the Inquisition.
Galileo was born on 15 February 1564 in Pisa, Duchy of Florence. He was the eldest of five siblings. His father was Vincenzo Galilei, who was a scholar and a musician. In 1574, the Galileo family moved to Florence and he started his formal education in the Camaldolese monastery.
Some people believe that Galileo was the first person to build a telescope. This is not true, but he was the first person to publish his observations of astronomical objects through a telescope. He discovered that the Milky Way is made of many stars. He discovered that the Moon has hills. He found four moons around Jupiter. Those moons are now called the Galilean moons. He discovered sunspots, which are dark areas of the Sun. He saw that the planet Venus has light and dark phases just like the Moon. This helped people to know that the Sun is at the centre of the Solar System, as Nicolaus Copernicus had said.
Galileo worked more at physics than at astronomy. He studied natural forces, and was one of the most important discoverers of the part of physics that is now called kinematics, including the discovery of the kinematic principle of relativity. However, he is often remembered now for things that either did not happen, or failed.
A legend says that he climbed the Leaning Tower of Pisa, and dropped cannonballs of different weights, to see which would strike the ground first. Even though their weights were not the same, they hit the ground at the same time. Galileo found that objects fall to the ground at the same rate, unless things like wind resistance change the rate. This went against the views of Aristotle, an ancient philosopher whose theory was different. Galileo's findings were ignored by most people, and Aristotle's view was still accepted as correct until Isaac Newton proved Galileo was right. This also led to Newton creating his Law of Gravity.
Galileo also tried to determine the speed of light. He climbed a hill, and had an assistant climb another hill, both carrying lanterns with closed shutters. He then opened the shutter of his lantern. His assistant opened his own shutter when he saw Galileo's lantern. Galileo then measured the time it took for his assistant's shutter to open. Knowing the time difference, and the distance between the hills, he tried to estimate the speed of light. However, this did not work.
The most important are:
Galileo came to accept the findings of Copernicus, that the Sun was the center of the then-known universe, and not the Earth. Because he promoted this and other ideas, he came to the notice of the Committee of Propaganda, the dreaded Inquisition. The Church taught that the Earth stood still, while everything in the sky moved around it. The Inquisition ruled in 1616 that other theories could only be discussed as possibilities, not facts. Galileo said he would obey. He played a major part in the scientific revolution through this argument.
Galileo later discussed the question in his most famous work, "Dialogue Concerning the Two Chief World Systems", published in 1632 by permission of the Inquisition. His scientific writing was usually in Latin for hundreds of scientists around Europe, but this was one of the books he wrote in Italian so thousands of Italians could read it. The book was in the form of conversations between three men. The man representing the Church's point of view was called 'Simplicio'.
Church leaders who liked his earlier books were angry at this one. The Inquisition took action in 1633. He was arrested and put on trial. They found him "vehemently suspect of heresy". They reminded him of the fate of Giordano Bruno, who had been burnt at the stake for heresy on topics such as transubstantiation and the Trinity. Bruno also believed the Earth went round the Sun and stars had planets. The Inquisition forced Galileo to recant (say he was wrong) under the threat of execution, and to withdraw his works from publication. Galileo spent the last ten years of his life under house arrest. Galileo continued to write about physics and other topics, but not astronomy.
Galileo has become synonymous with a warrior for scientific truth. Although he had to retract his writings at his trial, it is widely believed that after the trial he insisted that Earth does move around the sun, saying the famous phrase ""Eppur si muove"' – "still it moves." The saying itself became a slogan for science.
Galileo Galilei died on in Arcetri, Grand Duchy of Tuscany, Italy.
Previously, he was buried in a small room next to the novices' chapel at the end of a corridor. Later, he was reburied in the main body of the basilica in 1737 after a monument had been built there in his honour.
When a person agrees to do something or to "not" do something, that person is making a promise. A promise can be made (by saying it), or it can be written down as a contract. "Breaking" a promise, or not keeping it, is often just bad manners, but it can sometimes be illegal, such as when a contract is not kept.
A vow is a special promise. It is mostly used in a religious sense or in ceremonies such as marriages when the couple who are being married make their "marriage vows", promising to be faithful to one another.
An oath is a promise in the legal sense. When someone has to give evidence in a court of law they "swear an oath". This means that they promise they will tell the truth.
A cloud is water vapour in the atmosphere (sky) that has condensed into very small water droplets or ice crystals that appear in visible shapes or formations above the ground.
Water on the Earth evaporates (turns into an invisible gas) and rises up into the sky. Higher up where the air is colder, the water condenses: it changes from a gas to drops of water or crystals of ice. We see these drops of water as clouds. The drops fall back down to earth as rain, and then the water evaporates again. This is called the "water cycle".
The atmosphere always has some water vapour. Clouds form when the atmosphere can no longer hold all the invisible air vapor. Any more water vapor condenses into very small water drops.
Warm air holds more water vapor than cool air. So if warm air with lots of water inside cools, it can form a cloud. These are ways air can cool enough to form clouds:
Clouds are heavy. The water in a cloud can have a mass of several million tons. Every cubic metre (m3) of the cloud has only about 5 grams of water in it. Cloud droplets are also about 1000 times heavier than evaporated water, so they are much heavier than air. They do not fall, but stay in the air, because there is warm air all round the heavier water droplets. When water changes from gas to droplets, this makes heat. Because the droplets are very small, they "stick" to the warm air.
Sometimes, clouds appear to be brilliant colors at sunrise or sunset. This is due to dust particles in the air.
Clouds are classified according to how they look and how high the base of the cloud is in the sky. This system was suggested in 1803. There are different sorts of clouds because the air where they form can be still or moving forward or up and down at different speeds. Very thick clouds with large enough water droplets can make rain or snow, and the biggest clouds can make thunder and lightning.
There are five basic families of clouds based on how they look:
The following is a summary of the main cloud types arranged by how high they form:
High clouds form from in cold places, in mild regions and in the very hot tropics. They are too high and thin to produce rain or snow.
High-level clouds include:
Middle clouds usually form at in colder areas. However, they may form as high as in the tropics where it's very warm all year. Middle clouds are usually made of water droplets but may also have some ice crystals. They occasionally produce rain or snow that usually evaporates before reaching the ground.
Medium-level clouds include:
Low-level clouds are usually seen from near ground level to as high as . Low clouds are usually made of water droplets and may occasionally produce very light rain, drizzle, or snow.
Low-level clouds include:
When very low stratus cloud touches the ground, it is called fog.
These are clouds of medium thickness that can form anywhere from near ground level to as high as . Medium-level cumulus does not have "alto" added to its name. The tops of these clouds are usually not much higher than . Vertical clouds often create rain and snow. They are made mostly of water droplets, but when they push up through cold higher levels they may also have ice crystals.
Moderate-vertical clouds include:
These clouds are very tall with tops usually higher than . They can create heavy rain and snow showers. Cumulonimbus, the biggest clouds of all, can also produce thunderstorms. These clouds are mostly made of water droplets, but the tops of very large cumulonimbus clouds are often made mostly of ice crystals.
Towering-vertical clouds include:
In the Bible, clouds are often a sign of God's presence.
Water cycle
The water cycle (or hydrological cycle) is the cycle that water goes through on Earth.
Water is essential for life as we know it. It is present throughout the Solar System, and was part of the Earth from its formation. The source of the water was the same as the source of the Earth's rock : the cloud particles which condensed in the origin of the solar system.
This is the process that water starts and ends in the water cycle.
Human activities that change the water cycle include:
Water vapor
Water vapor is water that is in the form of a vapor, or gas. It is a part of the water cycle. When liquid water is heated to boiling point, 100 degrees Celsius (212 F), it turns into vapor. Water vapor can also be produced directly from ice; this is called sublimation. Steam is water vapor, but clouds are liquid water. The amount of water vapor in air is called humidity and it affects weather conditions. In the cold, breathing out causes the water vapor in the breath to freeze.
Water vapor weighs less than air, thus slightly reduces the lift produced by an aircraft wing.
Water vapour is transparent. The small droplets that look white like mist are actually liquid.
Water vapour is a big cause of the greenhouse effect.
Water vapor is invisible but when it condenses it makes visible water.
Solid is one of the three common states of matter. The molecules in solids are closely bound together, they can only vibrate. This means solids have a definite shape that only changes when a force is applied. This is different to liquids and gases which move randomly, a process called flow.
When a solid becomes a liquid, this is called melting. Liquids become solid by freezing. Some solids, like dry ice, can turn into gas without turning liquid first. This is called sublimation.
The forces between the atoms in a solid can take many forms. For example, a crystal of sodium chloride (common salt) is made up of ionic sodium and chlorine, which are held together by ionic bonds. In diamond or silicon, the atoms share electrons and make covalent bonds. In metals, electrons are shared in metallic bonding. Some solids, like most organic compounds, are held together with "van der Waals forces" coming from the polarization of the electronic charge cloud on each molecule. The dissimilarities between the types of solid come from the differences between their bonding.
Most metals are strong, dense, and good conductors of electricity and heat. The mass of the elements in the periodic table, those to the left of a diagonal line drawn from boron to polonium, are metals. Mixtures of two or more elements in which the big component is a metal are known as alloys.
People have been using metals for many purposes since prehistoric times.
The strength and relialbility of metals has led to their widespread use in making of buildings and other things, as well as in most vehicles, many tools, pipes, road signs and railroad tracks. Iron and aluminium are the two most commonly used metals. They are also the most common metals in the Earth's crust. Iron is most commonly used in the form of an alloy, steel, which has up to 2.1% carbon, making it much harder than pure iron.
Minerals are natural solids formed through many geological processes under high pressures. To be thought as a true mineral, a substance must have a crystal structure with uniform physical things throughout. Minerals differ in composition from pure elements and simple salts to very complex silicates with thousands of known forms. In contrast, a rock sample is a random aggregate of minerals and/or mineraloids, and has no specific chemical composition. Most of the rocks of the Earth's crust have quartz (crystalline SiO), feldspar, mica, chlorite, kaolin, calcite, epidote, olivine, augite, hornblende, magnetite, hematite, limonite and a few other minerals. Some minerals, like quartz, mica or feldspar are common, while others have been found in only a few places in the world. The largest group of minerals by far is the silicates (most rocks are ≥95% silicates), which are made largely of silicon and oxygen, also with ions of aluminium, magnesium, iron, calcium and other metals.
Evaporation is when a liquid becomes a gas without forming bubbles inside the liquid volume. If bubbles are formed we are talking instead about "boiling".
For example, water left in a bowl will slowly disappear. The water evaporates into water vapor, the gas phase of water. The water vapor mixes with the air.
The opposite of evaporation is condensation.
When the molecules in a liquid are heated, they move faster. This makes them full of energy and so the particles collide with each other, and eventually they become so far apart that they become a gas.
During evaporation only the molecules near the liquid surface are changing from liquid to vapor. During boiling the molecules inside the volume of the liquid are also changing to vapor. For this reason during evaporation no bubbles are formed, instead they are formed during boiling.
Evaporation can happen at any temperature, while boiling happens only at a specified temperature called the "boiling point". Evaporation happens slowly, but boiling happens quickly.
Some liquids evaporate more quickly than others. There are many factors that affect the evaporation rate.
The rate of evaporation depends on the liquid's exposed surface area (faster when increased), the humidity of surroundings (slower when increased), the presence of wind (faster when increased) and the temperature (faster when increased).
Liquid with high boiling points (those that boil at very high temperatures) tend to evaporate more slowly than those with lower boiling temperatures.
Evaporation is a very essential part of the water cycle.
A contract is an agreement or promise that the law can enforce. The law will enforce some agreements but not others. For example, in most places, if a parent promises to take a child to get ice cream, the law will not enforce that promise as a legal contract.
The legal rules about which promises are enforced by the law can be different in different places (or jurisdictions), but a contract is usually enforced only if it is made by people or groups who want it to be enforced and who know what they are doing.
Sometimes, a contract is written down and signed by the people agreeing to it, but it does not always need to be. People usually sign a contract when something important or costly is being done. For example, when people take a job, they will sometimes sign a contract with their employers. The contract will show what the person must do as part of his job, how much they will be paid, and so on. The person and the employer will sign the contract, and it will become a legal promise.
If someone breaks a contract, another person might sue him or her. In a lawsuit about a contract, the court will look at the contract, listen to what the people who made the contract say about it, and then make a decision about what the contract means.
The face is a part of the body at the front of the head.
It is the part of us that others interact with. On the face are organs of sight, smell, hearing. Especially in a four-legged animal, the face is the part which goes first into the world, and that is why the sense organs and the mouth are there.
In humans, the face includes the hair, forehead, eyebrow, eyelash, eyes, nose, ears, cheeks, mouth, lips, teeth, skin, and chin.
Kolkata
Kolkata (spelled Calcutta before 1 January 2001) is the capital city of the Indian state of West Bengal. It is the second largest city in India after Mumbai. It is on the east bank of the River Hooghly. When it is called Calcutta, it includes the suburbs. This makes it the third largest city of India. This also makes it the world's 8th largest metropolitan area as defined by the United Nations. Kolkata served as the capital of India during the British Raj until 1911. Kolkata was once the center of industry and education. However, it has witnessed political violence and economic problems since 1954. Since 2000, Kolkata has grown due to economic growth. Like other metropolitan cities in India, Kolkata struggles with poverty, pollution and traffic congestion.
The discovery of the nearby Chandraketugarh, an archaeological site has proved that people have lived there for over two millennia. The history of Kolkata begins when the English East India Company arrived in 1690. Job Charnock, an administrator with the Company is traditionally known as the founder of this city. However some academics say that Charnock is not the city's founder.
At that time Kolkata, ruled by the Nawab of Bengal Siraj-Ud-Daulah, had three villages. They were Kalikata, Govindapur and Sutanuti. The British in the late 17th century wanted to build a fort near Govindapur. This was to become more powerful than Dutch, the Portuguese, and the French. In 1702, the British completed the construction of old Fort William, which was used to station its troops and as a regional base. Calcutta was declared a Presidency City, and later became the headquarters of the Bengal Presidency. When regular fights with French forces started, in 1756 the British began to upgrade their fortifications. When this was protested, the Nawab of Bengal Siraj-Ud-Daulah attacked and captured Fort William. This led to the infamous Black Hole incident. A force of Company sepoys and British troops led by Robert Clive recaptured the city the next year. Calcutta became the capital of British India in 1772. However, the capital shifted to the hilly town of Shimla during the summer months every year, starting from the year 1864. Richard Wellesley, the Governor General between 1797–1805, helped in the growth of the city and its public architecture. This led to the description of Calcutta as "The City of Palaces". The city was a centre of the British East India Company's opium trade during the 18th and 19th century; locally produced opium was sold at auction in Kolkata, to be shipped to China.
A pencil is a kind of writing equipment that is also used to draw, usually on paper. Most pencil cores are made of graphite powder mixed with a clay binder. So, a pencil is usually made with a piece of graphite mixed with clay that has a wood case around it. The shape is usually a hexagonal prism but some pencils are square or cylinder.
Colored pencils are a kind that do not use greyish silver graphite. Instead, the core is colorful. Colored pencils or crayons are usually meant for drawing rather than writing.
The important difference between pens and pencils is that the tip of a pencil is made of solid graphite (or other material) which is rubbed off onto the paper. A pen has a tip, usually made of metal, with liquid ink coming out and onto the paper. Writing with a pen can smudge when it is still wet. Writing from a pencil can be erased, but writing from a pen usually cannot, unless it uses a special type of ink and eraser.
An early writing tool was the reed pen used by ancient Egyptians, who wrote with ink on sheets of papyrus paper.
Another early writing instrument was the stylus, which was a thin metal stick, often made from lead. It was used for scratching onto black wax that covered white wood, a method used by the Romans. The word "pencil" comes from the Latin word which means "little tail". It is an invention of the 16th century in England.
Some time before 1565 (it may have been as early as 1500), an enormous deposit of graphite was discovered in Borrowdale, Cumbria. The locals found that it was very useful for marking sheep. This particular deposit of graphite was extremely pure and solid, and it could easily be sawn into sticks. This is still the only large scale deposit of graphite ever found in this solid form. Chemistry was in its infancy and the substance was thought to be a form of lead. Consequently, it was called "plumbago" (Latin for "lead ore"). The black core of pencils is still referred to as "lead", even though it never contained the element lead.
The value of graphite was soon realized, mainly because it could be used to line the moulds for cannonballs. The mines were taken over by the Crown and guarded. When sufficient stocks of graphite had been accumulated, the mines were flooded to prevent theft until more was required. Graphite had to be smuggled out for use in pencils. Because graphite is soft, it requires some form of holder. Graphite sticks were at first wrapped in string or in sheepskin for stability. The news of the usefulness of these early pencils spread far and wide, attracting the attention of artists all over the known world.
England continued to have a monopoly on the production of pencils until a method of reconstituting the graphite powder was found. The distinctively square English pencils continued to be made with sticks cut from natural graphite into the 1860s. The town of Keswick, near the original findings of block graphite, has a pencil museum.
The first attempt to manufacture graphite sticks from powdered graphite was in Nuremberg, Germany, in 1662. It used a mixture of graphite, sulphur, and antimony.
Residual graphite from a pencil stick is not poisonous, and graphite is harmless if consumed.
The Italians first thought of wooden holders. In 1560, an Italian couple named Simonio and Lyndiana Bernacotti created the first blueprints for the modern carpentry pencil to mark their carpentry pieces. Their version was instead a flat, oval, more compact type of pencil. They did this at first by hollowing out a stick of juniper wood. Shortly thereafter, a superior technique was discovered: two wooden halves were carved, a graphite stick inserted, and the two halves then glued together–essentially the same method in use to this day.
English and German pencils were not available to the French during the Napoleonic Wars. France was under naval blockade imposed by Great Britain and could not import the pure graphite sticks from the British Grey Knotts mines – the only known source in the world for solid graphite. France was also unable to import the inferior German graphite pencil substitute. It took the efforts of an officer in Napoleon's army to change this. In 1795, Nicholas Jacques Conté discovered a method of mixing powdered graphite with clay and forming the mixture into rods that were then fired in a kiln. By varying the ratio of graphite to clay, the hardness of the graphite rod could also be varied. This method of manufacture, which had been earlier discovered by the Austrian Joseph Hardtmuth of Koh-I-Noor in 1790, remains in use.
In England, pencils continued to be made from whole sawn graphite. Henry Bessemer's first successful invention (1838) was a method of compressing graphite powder into solid graphite thus allowing the waste from sawing to be reused.
American colonists imported pencils from Europe until after the American Revolution. Benjamin Franklin advertised pencils for sale in his "Pennsylvania Gazette" in 1729, and George Washington used a three-inch pencil when he surveyed the Ohio Territory in 1762. It is said that William Munroe, a cabinetmaker in Concord, Massachusetts, made the first American wood pencils in 1812. This was not the only pencil-making occurring in Concord. Henry David Thoreau discovered how to make a good pencil out of inferior graphite using clay as the binder; this invention was prompted by his father's pencil factory in Concord, which employed graphite found in New Hampshire in 1821 by Charles Dunbar.
On 30 March 1858, Hymen Lipman received the first patent for attaching an eraser to the end of a pencil. In 1862 Lipman sold his patent to Joseph Reckendorfer for $100,000, who went to sue the pencil manufacturer Faber-Castell for infringement. In 1875, the Supreme Court of the United States ruled against Reckendorfer declaring the patent invalid.
The metal band used to mate the eraser with pencil is called a ferrule.
The first attempt to manufacture graphite sticks from powdered graphite was in Nuremberg, Germany in 1662. They used a mixture of graphite, sulfur and antimony. Though usable, they were not as good as the English pencils.
English and German pencils were not available to the French during the Napoleonic wars. It took the efforts of an officer in Napoleon's army to change this. In 1795 Nicholas Jacques Conté discovered a method of mixing powdered graphite with clay and forming the mixture into rods which were then fired in a kiln. By varying the ratio of graphite to clay, the hardness of the graphite rod could also be varied (the more clay, the harder the pencil, and the lighter the color of the mark). This method of making pencils is still used today.
Today, pencils are made industrially by mixing finely ground graphite and clay powders, adding water, forming long spaghetti-like strings, and firing them in a kiln. The resulting strings are dipped in oil or molten wax which seeps into the tiny holes of the material, resulting in smoother writing. A juniper or incense-cedar plank with several long parallel grooves is cut to make something called a slate, and the graphite/clay strings are inserted into the grooves. Another grooved plank is glued on top, and the whole thing is then cut into individual pencils, which are then varnished or painted.
A few common brands of colored pencils (among other items) are Crayola, RoseArt and Cra-Z-Art.
Logic is the study of reasoning. The rules of logic let philosophers make valid logical deductions about the world. Logic helps people decide whether something is true or false.
Logic is often written in syllogisms, which are one type of logical proof. A syllogism is made from a collection of statements used to logically prove the final statement, called the conclusion. One popular example of a logical syllogism was written by the Classical Greek philosopher Aristotle:
The conclusion is the final statement. This syllogism connects the first two statements to make a logical deduction: Socrates is mortal.
The syllogism is made from three logical statements or propositions. These statements are short sentences describing a small step in a logical argument. The small statements make up the argument, the same way atoms make up molecules. When logic is correct, the statements are said to "follow" from each other.
Statements have a truth value, meaning they can be proved to be true "or" false, but not both. Illogical statements or mistakes in logic are called logical fallacies.
Logical statements can be written in a special type of short hand writing, which includes the symbols of the symbolic logic. These symbols are used to describe logical reasoning in an abstract way. For example:
Here is the previous syllogism written in symbolic logic.
By replacing the English words with letters, one can make the syllogism even simpler.
Similar to mathematical symbols for operations like addition and subtraction, symbolic logic separates abstract logic from the English-language meaning of the original statements. With these abstract symbols, people can study pure logic without the use of a specific written language.
The syllogism is now written in the most abstract and simple way possible. Any distracting elements, such as English language words, have been removed. Anyone who understands logical symbolism can understand this argument.
A logical proof is a list of statements put in a specific order to prove a logical point. Each statement in the proof is either an assumption made for the sake of argument, or has been proven to follow from earlier statements in the proof. All proofs must start with some assumptions, such as "humans exist" in the above syllogism. A proof shows that one statement, the conclusion, follows from the starting assumptions. With a proof, we can prove that "Aristotle is mortal" logically follows from "Aristotle is a man" and "All men are mortal".
Some statements are always true. That kind of statement is called tautology"." One popular classical tautology, credited to the philosopher Parmenides of Elea, says "That which is, is. That which is not, is not." This essentially means that true statements are true and false statements are false. Due to their simple nature, tautologies may not always be helpful in building logical arguments.
A tautology is represented in symbolic logic as formula_9, meaning "Either "a" or not "a"." Assuming that there are no unmentioned possibilities, this covers every possible case. Another symbol used to represent a tautology is formula_10.
Because logic is a tool used to think more rationally, it can be used in countless ways. Symbolic logic is employed far and wide, from philosophical treatises to complicated mathematical equations. Computers use the rules of logic to run algorithms, which let computer programs make decisions based on data.
Logic is critical to pure mathematics, statistics, and data analysis. Logic is also studied in philosophy. People who study math create proofs that use logical rules to show that mathematical theorems are correct. There is an area of mathematics called mathematical logic that studies logic using mathematics.
Communism is a socio-economic political movement. Its goal is to set up a version of society where the factories and farms are shared by the people, and would not have rulers or money.
According to communist writers and thinkers, the goal of communism is to create a society without a government or a system of classes, and to end capitalism. Communist thinkers believe this can happen if the people take away the power of the bourgeoisie (the ruling class, who own the factories and farms) and establish worker control of the means of production (factories and farms).
Communism is not anti-individualist. However, it does also say that decisions should be good for the population as a whole, instead of just being good for only a few of people in the country.
Since 1992, there have been five nations remaining governed officially by communist ideologies. Four of these follow different forms of Marxism-Leninism - Vietnam, China, Cuba and Laos. The fifth, North Korea, now officially follows Juche, which claims to be a better version of Marxism-Leninism. North Korea called itself Marxist-Leninist before 1991. Many other nations abandoned Marxism around that time because most people thought it had failed. In many cases Marxist governments fell to authoritarianism, mass poverty, economic collapse and violent conflict, as is the case of the Soviet Union and Yugoslavia, for example.
Some of the most well-known people that have been important in the development of communism include Karl Marx, Friedrich Engels, Joseph Stalin, Mao Zedong, Vladimir Lenin, and Leon Trotsky.
In 1848, Karl H. Marx and Friedrich Engels wrote "The Communist Manifesto". It was a short book with the basic ideas of communism. Most socialists and communists today still use this book to help them understand politics and economics. Many non-communists read it too, even if they do not agree with everything in it.
Karl Marx said that for society to change into a communist way of living, there would have to be a period of change. During this period, the workers would govern society. Marx was very interested in the experience of the Paris Commune of 1870, when the workers of Paris ran the city following the defeat of the French Army by the Prussian Army. He thought that this practical experience was more important than the theoretical views of the various radical groups.
Many groups and individuals liked Marx's ideas. By the beginning of the twentieth century, there was a worldwide socialist movement called Social Democracy. It was influenced by his ideas. They said that the workers in different countries had more in common with each other than the workers had in common with the bosses within their own countries. In 1917, Vladimir Lenin and Leon Trotsky led a Russian group called the Bolsheviks in the October Revolution. They got rid of the temporary government of Russia, which was formed after the February Revolution against the Tsar (Emperor). They established the Union of Soviet Socialist Republics, also called the Soviet Union or USSR.
The Soviet Union was the first country claiming to have established a workers' state. In reality, the country never became communist in the way that Marx and Engels described.
During the 20th century, many people tried to establish workers' states. In the late 1940s, China also had a revolution and created a new government with Mao Zedong as its leader. In 1959, the island of Cuba had a revolution and created a new government with Fidel Castro as its leader. At one time, there were many such countries, and it seemed as though communism would overtake Capitalism. However, communist party governments didn't use democracy, which is a very important component of socialism and communism. Because of this, the governments became separated from the people, making communism difficult. This also led to disagreements and splits between countries.
By the 1960s, one-third of the world had overthrown capitalism and were trying to build communism. Most of these countries followed the model of the Soviet Union. Some followed the model of China. The other two-thirds of the world still lived in capitalism, and this led to a worldwide divide between capitalist countries and communist countries. This was called the "Cold War" because it was not fought with weapons or armies, but competing ideas. However, this could have turned into a large war. During the 1980s, the United States and the Soviet Union were competing to have the biggest army and having the most dangerous weapons. This was called the "Arms Race". President Ronald Reagan called communist countries like the Soviet Union the "Evil Empire" because he did not agree with communist ideas.
Since 1989, when the Berlin Wall was torn down, most countries that used to be communist have returned to capitalism. Communism now has much less influence around the world. In 1991, the Soviet Union broke up. However, around a fifth of the world's people still live in states controlled by a communist party. Most of these people are in China. The other countries include Cuba, Vietnam, Laos, and North Korea. There are also communist movements in Latin America and South Africa.
Many people have written their own ideas about communism. Vladimir Lenin of Russia thought that there had to be a group of hard-working revolutionaries (called a vanguard) to lead a socialist revolution worldwide and create a communist society everywhere. Leon Trotsky, also from Russia, argued that socialism had to be international, and it was not important to make it happen first in Russia. He also did not like Joseph Stalin, who became the leader of the USSR after Lenin's death in 1924. Trotsky was made to leave the Soviet Union by Stalin in 1928, and then killed in 1940. This scared many people, and lots of communists argued about whether this was right and whose ideas should be followed.
Mao Zedong of China thought that other classes would be important to the revolution in China and other developing countries because the working classes in these countries were small. Mao's ideas on communism are usually called Maoism or Mao Zedong Thought. After Stalin's death in 1953, Mao saw himself as the leader of worldwide communism until he died in 1976. Today the Chinese government is still ruled by the Communist Party, but they actually have what is called a mixed economy. They have borrowed many things from capitalism. The government in China today does not follow Maoism. However, few revolutionaries in other countries like India and Nepal still like his ideas and are trying to use them in their own countries.
The word "communism" is not a very specific description of left-wing political organizations. Many political parties calling themselves "communist" may actually be more reformist (supportive of reforms and slow change instead of revolution) than some parties calling themselves "socialists". Many communist parties in Latin America have lost many members because these parties do different things than what they promised once they get into power. In Chile, between 1970-1973, under the left-wing Coalition (groups of parties) of Popular Unity, led by Salvador Allende, the Communist Party of Chile was to the right of the Socialist Party of Chile. This means it was more reformist than the socialist party.
Many communist parties will use a reformist strategy. They say working-class people are not organized enough to make big changes to their societies. They put forward candidates that will be elected democratically. Once communists become elected to parliament or the Senate, then they will fight for the working class. This will allow working-class people to change their capitalist society into a socialist one.
The color red is a symbol of communism around the world. A red five-pointed star sometimes also stands for communism. The hammer and sickle is a well-known symbol of communism. It was on the flags of many communist countries, like the Soviet Union (see top of article). Some communists also like to use pictures of famous communists from history, such as Marx, Lenin, and Mao Zedong, as symbols of the whole philosophy of communism.
A song called "The Internationale" is the international song of communism. It has the same music everywhere, but the words to the song are translated into many languages. The Russian version was the national anthem of the Soviet Union from 1922 until 1944.
The sickle in the Soviet Union's flag shows the struggle of the peasants-farmers. The hammer in the flag represents the struggle for the workers. Both of them crossing shows their support for each other.
There is also a special kind of art and architecture found in many communist and former communist countries. Paintings done in the style of socialist realism are often done for propaganda to show a perfect version of a country's people and political leader. Art done in the socialist realism style, such as plays, movies, novels, and paintings show hard-working, happy, and well-fed factory workers and farmers. Movies, plays and novels in this style often tell stories about workers or soldiers who sacrifice themselves for the good of their country. Paintings often showed heroic portraits of the leader, or landscapes showing huge fields of wheat. Stalinist architecture was supposed to represent the power and glory of the state and its political leader. Some non-communists also enjoy this kind of art.
Resurrection means bringing someone back to life after they have died.
The idea of resurrection is found in writings of ancient polytheistic religions in the Middle East. Some Egyptian and Canaanite writings tell of gods being resurrected, such as Osiris and Baal.
In Greek mythology, many men and women were given eternal life by being resurrected from the dead. In their stories, some who came back to life as gods were Alcmene, Castor, Heracles, and Melicertes. But the Greek philosophers at that time did not believe in a physical rebirth.
Christians believe that Jesus Christ was resurrected. They also believe in resurrection for all people after they die. This is based on the Gospels and on Saint Paul's writings in the New Testament. The resurrection of Jesus is the Christian belief that he returned to life by a miracle. He died by crucifixion on Friday and rose from his tomb to new life on Sunday morning. This belief is celebrated at Easter.
The resurrection of Jesus Christ is written about by the evangelists in the New Testament. They are the authors of the four Gospels in the New Testament. Christians believe the resurrection is a central part of the Christian faith. Jesus died on the cross to save mankind. When he was resurrected, Jesus defeated death. He is alive forever and sitting at God's right hand on a throne. This gives Christians the hope of a new life after death. This is because his resurrection mirrors the future for all Christians after they die.
With Jesus Christ and with humans, the Bible shows that the resurrected body is changed from the original. This is because the human body, while alive, is weak and frail. But, the resurrected person lives for ever.
All four Gospels tell about Jesus being raised from the dead. They also write about three times that Jesus brings a dead person back to life:
In Islam, the Quran refers to a bodily resurrection of all those who have died.
This will be followed by a final time of trouble and eternal division of the righteous and wicked. Islamic apocalyptic literature describing Armageddon is often known as The Great Massacre or "ghaybah" in Shī'a Islam. The righteous are rewarded with the pleasures of Jannah (Paradise), while the unrighteous are punished in Hell.
According to Alcor, resurrection of a legally dead people will be possible in the far future. They are using Cryonics to preserve some legally dead people until the invention of the resurrection.
A monarchy is a kind of government where a monarch, a kind of hereditary ruler (someone who inherits their office), is the head of state. Monarchs usually rule until they die or pass down (when a monarch resigns it is called abdication). Most monarchies are hereditary, but some are elected. The most famous elected monarch is the Pope of the Roman Catholic Church. Some well known titles for monarchs are King, Queen, Emperor, Empress, Czar, Kaiser, Shah, Emir and Sultan.
Monarchy is one of the oldest kinds of government. Most historians agree that the first monarchies were tribes or small groups of people who decided to let a war-chief or other leader pass on their office to their children. This created a dynasty. Over time, the rules for deciding who got to become the next monarch became more complicated. Primogeniture is usual. The oldest son or, in some countries, daughter, becomes the next monarch when the old one dies.
Kings and other kinds of monarchs have ruled for many thousands of years; for example, many kings are mentioned in the Bible and in ancient historical records. Three of the oldest countries with monarchs that still hold office are the United Kingdom, which has had the same British Royal Family for nearly 1,000 years, Denmark where the royal line has remained unbroken for almost 1,200 years, and Japan, which has records showing a line of Emperors dating back even farther.
Many monarchs today perform mostly the ceremonial jobs of a head of state, while the head of government, who is usually elected, passes and enforces laws. It is also very important in other parts of the country.