Aarushhh/wikipedia-simple-splitted huggingface dataset:
Media in Essen 

The WDR (Westdeutscher Rundfunk/Western German Broadcasting) has a TV-station in Essen. The two biggest newspapers, the WAZ (Westdeutsche Allgemeine Zeitung/Western German common newspaper) and the NRZ, the Neue Ruhr Zeitung/New Ruhr newspaper (at the lower Rhine regionNeue Rhein Zeitung/New Rhein newspaper) are in the city. Both newspapers belong to the WAZ-media group. Essen also has a radio station named Radio Essen.

Boroughs of Essen
Essen has nine districts (Bezirke) and 50 boroughs (Stadtteile). The most famous and most known are Kettwig, until 1975 a separate town and not part of Essen, with the Altstadt of Kettwig, where many timber framing houses are (Fachwerkhäuser). Also well-known is Werden. It lays like Kettwig in the south of the city and is the oldest borough of Essen. The Werden abbey stands here. In Essen-Rüttenscheid there are many cultural buildings (like the Folkwang or the Ruhrland museum). The WDR-studio and Essen's trade fair, the Gruga are also in Rüttenscheid. In the north of Essen is Katernberg, where in the past the coal mine workers lived. Here is Zeche Zollverein. In Katernberg, many houses were built by the Krupp family for their workers. Another big coal mine worker's borough, perhaps the biggest, is Margarethenhöhe near Rüttenscheid. It is named after Margarethe Krupp, wife of Friedrich Alfred Krupp. The Krupps wanted their workers to be absolutely dependent on them
. So they built houses and malls for them, where they should spend their money, what they got from Krupp, again to the industrials. Today Margarethenhöhe is one of the most beautiful boroughs of Essen. Another big borough of Essen is Steele in the east of the city, that was in the 19th and early 20th century a city as big as Essen. In the west of Essen is Borbeck, which was long separate from Essen. In Borbeck is the great Borbeck Castle (Schloss Borbeck). The people of Borbeck speak their own regional dialect, the Borbecker Platt.
The nine districts of Essen are:
 Bezirk I (Stadtmitte/Frillendorf/Huttrop)
 Bezirk II (Rüttenscheid/Bergerhausen/Rellinghausen/Stadtwald)
 Bezirk III (Essen-West)
 Bezirk IV (Borbeck)
 Bezirk V (Altenessen/Karnap/Vogelheim)
 Bezirk VI (Katernberg/Schonnebeck/Stoppenberg)
 Bezirk VII (Steele/Kray)
 Bezirk VIII (Ruhrhalbinsel)
 Bezirk IX (Werden/Kettwig/Bredeney)

Famous people in Essen
The most known people from Essen are the actor Heinz Rühmann, whose parents were the owner of Essen's famous hotel Handelshof near the Central Station (Hauptbahnhof), Carl Humann, explorer of the Great Altar of Pergamon, Karl Baedeker, a publisher whose company made many books for tourists (Baedeker), Alfred Krupp and Franz Dinndendahl, who made the first steam machine in the Ruhr area. These people were born in the city. Other people who were not born in Essen but lived and worked there a long time are Berthold Beitz, who saved the Krupp company from the ruin, Wilhelm Busch, a famous poet and painter or Gustav Heinemann, a German politician who was mayor of Essen and federal president of Germany. Other people like Otto von Bismarck and Paul von Hindenburg were honorary people in Essen.

Sport
Sport 

The most popular sport in Germany is Association football or soccer. The most important soccer clubs of Essen are Rot-Weiß Essen (RWE) and Schwarz-Weiß Essen. They play in the 4th and the 5th league. More successfully is the women's association football club SG Essen-Schönebeck that plays in the first Bundesliga.
The second big sport is team handball. TUSEM Essen is the most important club in Essen.
The most popular ice hockey club is named ESC Moskitos Essen and the biggest basketball club ETB Wohnbau Baskets Essen.
Essen also has many table tennis and swimming clubs.

Twin towns 
Essen's twin towns are:
  - Sunderland, since 1949
  - Tampere, since 1960
  - Grenoble, since 1974
  - Nizhny Novgorod, since 1991
  - Tel Aviv-Yafo, since 1991

References

Other websites

Imperial free cities
World Heritage Sites in Germany
Urban districts in Regierungsbezirk Düsseldorf
Gardening is the growing of plants such as flowers, shrubs and trees as a hobby or recreation. Some people also grow vegetables or fruit in their gardens. People do gardening outdoors in the soil in their backyard, or in pots or containers on their balcony or on their patio. Some people do gardening on a roof.

People do indoor gardening inside their house or inside a building. Sometimes indoor gardening is done in greenhouses, which are special buildings where plants are grown. A greenhouse has a transparent glass or plastic roof and walls that let sunlight in. Grow tent is also used for indoor plants. Grow tent helps plant to grow in a more spectacular and develop a friendly environment. Water gardening is growing plants in ornamental  water pools and ponds. People doing water gardening plant water lilies and other aquatic plants.
Gardening can be done outside of the home, in city parks, botanical gardens, zoos, amusement parks, theme parks, and around tourist attractions. These types of gardens are cared for by people called gardeners or groundskeepers.

Gardening compared with farming 
Gardening is related to farming. But farming is done on a much larger scale. A farm may have hundreds of square kilometres of plants and crops. A garden in a person's backyard usually only measures a few square meters. As well, farming is done as a business, to sell the crops, fruit, and vegetables that are produced. Gardening is often done just to produce fruit or vegetables for the gardener's own family. Gardening may be a hobby or a recreation. Gardening for sale is called "market gardening".
Gardening tools 
Gardeners use tools to dig in the soil and water the crops. These tools include a spade, a fork, a hoe, a basket, a watering can, a hose, a Sprinkler, a bucket, a trowel  and a wheelbarrow. With growing, technology gardeners now have tech like Self-watering containers, Garden sensors, Hydroponic systems and Indoor lighting systems.

Gardens as art 
In many countries and cultures, designing beautiful gardens is treated as a fine art. In Japan, for instance, Zen monks created Japanese gardens. In Europe in the 1700s, kings and queens had formal gardens built. One example is the gardens at the Versailles palace in Paris, France. Landscaping, the making of an artificial landscape, may include gardening and the designer may be a professional landscape architect.

Related pages
Agriculture
Horticulture
Aquaculture
Agronomy
Hydroculture

References
Democracy means rule by the people. There are different ways this can be done:
 People meet to decide about new laws, and changes to existing ones. This is usually called direct democracy. It is never used except in small countries, or perhaps in towns. Modern populations are usually too large to do this.
 The people elect their leaders. These leaders take decisions about laws. This is commonly called representative democracy. Elections are either held periodically, or when an officeholder dies.  
 Sometimes people can propose new laws or changes to existing laws. Usually, this is done using a referendum, a vote.
 Sometimes, people are chosen more or less at random. This is common, for example, when choosing a jury for a trial. In Europe, trials with a jury are usually used for serious crimes. However, many legal cases are not about crimes. They are about commercial issues. They are usually held without a jury, and decisions are made by the judge or judicial panel.
The type of government where power is in the hands of a single person is called a dictatorship. Democracy is the opposite of a dictatorship. The Soviet Union almost always was a dictatorship, as Russia is today. Dictatorships often act against freedom of expression. 

An important source of information is the Democracy Index published by the Economist periodical.

Types of government 
Elections are simple: The candidate with the most votes gets elected. Very often, the politicians being elected belongs to a political party. Instead of choosing a person, people vote for a party. The party with the most votes then picks the candidates.

Usually, the people being elected need to meet certain conditions: They need to have a certain age or a government body needs to determine that they are suitably qualified to perform the job.

Not everyone can vote in an election. Suffrage is only given to people who are citizens. The young are usually excluded, and some other groups such as prisoners.
For some elections, a country makes voting compulsory. Someone who does not vote and who does not give a good reason, usually has to pay a fine.

Kinds of democracy 
Democracy may be direct or indirect.

In a direct democracy, every adult has the right to vote on individual laws. A modern example of direct democracy is a referendum, which is the name for deciding a law where everyone in the community votes on it. Direct democracies are not usually used to run countries. It is not practical to have everyone voting on everything.

In an indirect, or representative democracy, people choose representatives to make laws for them. These people can be mayors, councilmen, members of Parliament, or other government officials. This is the usual kind of democracy. Large communities like cities and countries use this method, but it may not be needed for a small group.
Pseudo-democracy 
A term for democracies which are not actually democracies. For example, a constitution of a country may be democratic, but ways are found to interfere with elections. The classic case is Russia, where opposition candidates are not allowed to state their case on any of the state-controlled media. Elections for President are fixed, but the state can claim democratic legitimacy, because in principle other candidates may stand for election. Opposition candidates have no access to the media, and may be harassed in various ways. This is the way all the former parts of the Soviet Union are governed. This does not mean the governments are always bad governments. It does mean that holding "fixed" elections deprives the people of a fair vote. Not surprisingly, these countries have Presidents who are never beaten in an election. They may serve for eight years or longer before retiring. The next leaders are pre-chosen by discussion between the leading families.
The European Parliament says Russia functions as a unitary state despite officially being a federation.

History

Ancient origins 
Democracy was developed long ago by the ancient Greeks in classical Athens.  There, everyone who was a citizen (not slaves, women, foreigners, and children) got together in one area.  The assembly would talk about what kinds of laws they wanted and voted on them. The council would suggest the laws. All citizens were allowed in the assembly.

The council were picked by draws (lottery). The participants in the council would change every year, and the number of people in the council was at the most 500. For some offices, the Athenian citizens would pick a leader by writing the name of their favorite candidate on a piece of stone or wood. The person with the most votes became the leader.
Middle Ages 
In the Middle Ages, there were many systems, although only a few people could join in at this time. The Parliament of England began from the Magna Carta, a document which said that the King's power was limited, and protected certain rights of the people. The first elected parliament was De Montfort's Parliament in England in 1265.

However, only a few people could actually join in. Parliament was chosen by only a few percent of the people (in 1780, fewer than 3% of people joined in). The ruler also had the power to call parliaments. After a long time, the power of Parliament began to grow. After the Glorious Revolution in 1688, the English Bill of Rights 1689 made Parliament more powerful. Later, the king or queen became a symbol instead of having real power.

Democratic consolidation 
Democratic consolidation means how a new democracy matures. Once mature, it is unlikely to revert to dictatorship rule without an external shock.
The idea is that unconsolidated democracies suffer from intermittent elections which are not free and fair. In other words, powerful groups are able to prevent the system working fairly.

Related pages 

 Activism
 Citizenship
 Constitution
 Constitutional economics
 Democracy Index
 Direct democracy
 Election
 Majority rule
 Pluralism
 Political economy
 Political party
 Politics
 Proportional representation
 Rule of law
 Unicameralism
 Universal suffrage
 Women's suffrage

References
A game is something that people often do for fun. It is different from work. Many sports are games, and there are many professional sports. In those cases, there is money to be made, because it is a type of entertainment.

There are different kinds of games using many kinds of equipment. For example, in video games, people often use controllers or their keyboard to control what happens on a screen, such as a television screens and computers ones too.  In card games, players use playing cards.  There are also games that use your body, such as the Kinect. Most games need equipment, but not always. Children's street games often need no equipment.

In board games, players may move pieces on a flat surface called a board. The object of the game varies. In race-type games like ludo, the object is to reach the end first. In go the object is to surround more space. In soccer it is to score more goals. Some games have complicated rules, some have simple rules.

Definitions
Definitions

Ludwig Wittgenstein 
Ludwig Wittgenstein was probably the first academic philosopher to address the definition of the word game. In his Philosophical Investigations, Wittgenstein demonstrated that the elements (parts) of games, such as play, rules, and competition, all fail to correctly define what games are. He concluded that people apply the term game to a range of different human activities that are related, but not closely related.

Homo Ludens 
Homo Ludens (Playing Man) is a book written in 1938 by Dutch historian Johan Huizinga. It discusses the importance of the play element in culture and society. Huizinga suggests that play is a  condition for the generation of culture.

Roger Caillois 
French sociologist Roger Caillois, in his book Les jeux et les hommes (Games and Men), said that a game is an activity which is these things:
free: the activity is voluntary
 separate: the activity cannot happen everywhere or, all the time
uncertain: the people doing the activity do not know how it will end
non-productive: doing the activity does not make or do anything useful
governed by rules: the activity has rules that are different from everyday life
fictitious: the people doing the activity know that the game is not reality
Chris Crawford 
Computer game designer Chris Crawford tried to define the word game using a series of comparisons:
Something creative is art if it was made because it is beautiful, and entertainment if it was made for money. 
Something that is entertainment is a plaything if it is interactive. Movies and books are entertainment, but not interactive.
If a plaything does not have any goals to complete, it is a 'toy. If a plaything has goals, it is a challenge.
If a challenge does not have an opponent, it is a puzzle. If it has an opponent, it is a conflict. 
If the player can do better at something than an opponent but cannot affect the opponent, the conflict is a competition. Racing and figure skating are competitions. However, if attacks are allowed, then the conflict qualifies as a game.

Crawford's definition of a game is: an interactive, goal-oriented activity, with opponents to play against, and where players and opponents can interfere with each other.
History of Games 
The first writer of history was Herodotus, an ancient Greek. He wrote a book called “The Histories” around 440 BC, which is nearly 2500 years ago. Some of the stories he wrote were not true, and we don't know if this is one of those.

Herodotus tells us about king Atys; he ruled about 5,500 [five thousand five hundred] years ago in a country called Lydia. His country was in western Asia Minor, near modern Greece. Atys had a serious problem; his lands had very little food because the climate was not good for agriculture. The people of Lydia demonstrated patience and hoped that the good times of plenty would return.
But when things failed to get better, the people of Lydia thought up a strange solution for their problem. The path they took to fight their natural need to eat – the hungry times caused by the unusually hard climate - was to play games for one entire day so that they would not think about food. On the next day they would eat, so eating occurred every second day. In this way they passed 18 years, and in that time they invented dice, balls, and all the games commonly played today.

Games appear in all cultures all over the world, an ancient custom that brings people together for social opportunities. Games allow people to go beyond the limit of the immediate physical experience, to use their imagination. Common features of games include a finish that you cannot forecast, agreed upon rules, competition, separate place and time, imaginary elements, elements of chance, established goals and personal enjoyment. Games are used to teach, to build friendships, and to indicate status.
In March 2016 a Google computer program beat the best Go players in the world. Go is believed to be the most complex board game ever created. Is this computer program smarter than a person? Well, it did beat the South Korean Go master Lee Se-dol, and Lee was surprised by the result.  He acknowledged defeat after three and a half hours of play. Demis Hassabis, who made the Google program, called it an important moment in history, because a machine beat the best person in the world in an intelligent game.  Such computer programs rely on what is called artificial intelligence. Go is a two-player game of strategy said to have had an origin in China perhaps around 3,000 [three thousand] years ago. Players compete to win more territory by placing black and white “stones” on a board made up of 19 [nineteen] lines by 19 [nineteen] lines.
The first computer game that was ever created was probably the game OXO by Alexander Douglas in 1952.  It was a version of tic-tac-toe. But most people consider the first true computer game where players actually participate to be Tennis for Two developed in 1958 by the physics scientist William Higginbotham. He wanted to teach about gravity, the force of attraction between masses. These men who created the early computer games did not forecast the potential for the popular use of games, because at that period in modern history it took a small room full of computers to make these games work! Another early game was Spacewar! developed in 1961 by MIT university student Steve Russell. In 1972 the company Atari produced the Pong game which was a huge commercial success; being a commercial success means that it made a lot of money. This was the true beginning of computer games that could be played at home.
Today, all around the world people spend more than 3,000,000,000 [three billion] hours a week playing computer games. This is equivalent to more than 342,000 [three hundred and forty two hundred thousand] years!

 Other definitions 
 "A game is a system in which players engage in an artificial conflict, defined by rules, that results in a quantifiable outcome".
 "A game is a form of art in which participants, termed players, make decisions in order to manage resources through game tokens in the pursuit of a goal". (Greg Costikyan)
 "A game is an activity among two or more independent decision-makers seeking to achieve their objectives in some limiting context''".
 "At its most elementary level then we can define game as an exercise of voluntary control systems in which there is an opposition between forces, confined by a procedure and rules in order to produce a disequilibrial outcome".
 "A game is a form of play with goals and structure".

Related pages
Video game
Puzzle
Sports
Toy

References
Nebraska is a state near to the center of the United States. Its capital is Lincoln and the largest city is Omaha. It touches the states of Wyoming, South Dakota, Iowa, Missouri, Colorado and Kansas.

Nebraska is known for its agriculture, especially beef and corn.

Nebraska has hot summers and cold winters. A temperature of 30 °C (which is about 86 °F) is common in the summer, and in the winter it can be -20 °C (which is about -4 °F) or colder at night.

History
Native American tribes, including the Omaha, Oto, Missouri, Pawnee, Arapaho and Cheyenne, all ceded land in Nebraska to the U.S. government.

On May 30, 1854, the United States government made a law called the Kansas-Nebraska Act. It made two territories called Kansas Territory and Nebraska Territory. In the 1860s, many people moved there to take free land from the government. Nebraska became a state on March 1, 1867.

Related pages
 Colleges and universities in Nebraska
 List of counties in Nebraska

References
References

 
1867 establishments in the United States
Time is the never-ending continued progress of existence and events. It happens in an apparently irreversible way from the past, through the present and to the future.

To measure time, we can use anything that repeats itself regularly. One example is the start of a new day (as Earth rotates on its axis). Two more are the phases of the moon (as it orbits the Earth), and the seasons of the year (as the Earth orbits the Sun). 

Even in ancient times, people developed calendars to keep track of the number of days in a year. They also developed sundials that used the moving shadows cast by the sun through the day to measure times smaller than a day. Today, highly accurate clocks can measure time in  less than a billionth of a second. The study of time measurement is known as  horology.

The SI (International Systems of Units) unit of time is one second, written as s. When used as a variable in mathematics, time is often represented by the symbol .
Units of time 
 1 millennium = 10 centuries = 100 decades = 200 lustrums = 250 quadrenniums = 333.33 trienniums = 500 bienniums = 1,000 years
 1 century = 10 decades = 20 lustrums = 25 quadrenniums = 33.33 trienniums = 50 bienniums = 100 years
 1 decade = 2 lustrums = 2.5 quadrenniums = 3.33 trienniums = 5 bienniums = 10 years
 1 year = 12 months = 52 weeks = 365 days (366 days in leap years)
 1 month = 4 weeks = 2 fortnights = 28 to 31 days
 1 fortnight = 2 weeks = 14 days
 1 week = 7 days
 1 day = 24 hours
 1 hour = 60 minutes
 1 minute = 60 seconds
 1 second = SI base unit of time
 1 millisecond = 1/1,000 second
 1 microsecond = 1/1,000,000 second
 1 nanosecond = 1/1,000,000,000 second
 1 picosecond = 1/1,000,000,000,000 of a second
 1 femtosecond = 1/1,000,000,000,000,000 of a second
 1 attosecond = 1/1,000,000,000,000,000,000 of a second
 1 Planck time = smallest measurable unit of time

Things used to measure time 
 Clock
 Hourglass
 Stopwatch
 Sundial
 Circadian rhythm
Time of day 
 World Clock
 U.S. Naval Observatory 
 Time in   Hexadecimal numeral system

Related pages 

 Chronology
 24-hour clock
 Time zone
 Space-time

References 

Basic English 850 words
Philosophy
In physics, a force is a push or pull between objects. It is called an interaction because if one object acts on another, its action  is matched by a reaction from the other object. This idea is known as Newton's third law, where action and reaction are "equal and opposite"  (matched).
The objects are just the things the force acts between. Different forces act between different sorts of object. For example, gravity acts between objects with mass, like the sun and the earth. Another example is electromagnetic force, which acts between objects with charge, like an electron and the nucleus of an atom. Gravity and electromagnetic force are two examples of forces.
A force changes the state of an object (some physical quantity changes) or, strictly, the states of two objects, since the force is an interaction. For example, a force causes an affected object to be pushed or pulled in a certain direction. This  changes the object's momentum. Forces cause objects to accelerate, add to the object's overall pressure, change direction, or change shape. Because the magnitude and direction of a force are both important, force is a vector quantity. The strength of a force is measured in newtons (N).  There are four fundamental forces in physics.

A force is always a push, pull, or a twist, and it affects objects by pushing them up, pulling them down, pushing them to a side, or by changing their motion or shape in some other way.

Newton's Second Law 
According to Newton's Second Law of Motion, the formula for finding force is:

where  is the force, 
 is the mass of an object, 
and  is the acceleration of the object.
His second law defines a force to be equal to change in momentum (mass times velocity) per change in time. Momentum is defined to be the mass m of an object times its velocity V.

Weight 

Gravity is an acceleration. Everything that has a mass is being pulled toward the Earth because of that acceleration. This pull is a force called weight. 

One can take the equation above and change  to the standard gravity g, then a formula about the gravity on earth can be found:

where  is the weight of an object, 
 is the mass of an object, 
and  is the acceleration due to gravity at sea level. It is about .

This formula says that when you know the mass of an object, then you can calculate how much force there is on the object because of gravity.
You must be on earth to use this formula. If you are on the moon or another planet, then you can use the formula but g will be different.
Force is a vector, so it can be stronger or weaker and it can also point in different directions. 
Gravity always points down into the ground (if you are not in space).

Gravitational force 

Another equation that says something about gravity is:

 is force;  is the gravitational constant, which is used to show how gravity accelerates an object;  is the mass of one object;  is the mass of the second object; and  is the distance between the objects.

This equation is used to calculate how the earth moves around the sun and how the moon moves around the earth. It is also used to calculate how other planets, stars and objects in space move around.

The equation says that if two objects are very heavy then there is a strong force between them because of gravity.
If they are very far apart then the force is weaker.
The four forces of the Universe 
Objects and particles in the Universe interact. How the particles and object interact is governed by four forces of nature. They are:
Gravity
Electromagnetism
Strong force
Weak force

The Fermilab in the U.S. is a particle accelerator. They are investigating results which suggest a possible fifth force of nature.

References

Further reading
 Gravity
 
Basic physics ideas

gd:Neart
Laboratory techniques are the techniques of handling the various pieces of apparatus.

Basic techniques

Handling of chemicals

Ways to dissolve a solid in a liquid or to mix two liquids in a test tube:

 Shake the test tube gently
 Stir with a glass rod
 Tap the bottom of the test tube with your finger
 Pour the contents to and fro between two test tubes
 Stopper the test tube and shake

Heating techniques 

Hold the material over a naked flame
Put the material in a water bath
Use a type of hairdryer called a "heat gun" to blow hot air at the material.

Collecting gases 
 Upward and downward delivery
 Over water
 Gas syringe

Drying substances

Leave the mixture at room temperature to evaporate on its own.
Put the substance in an "oven" which heats it gently and removes water vapour.

Smelling gases
 Never smell a gas directly.
 Waft a gas towards yourself if it is reasonably safe to smell it.
 Never smell a gas that is toxic or otherwise dangerous.

Chemistry
The International System of Units is the standard modern form of the metric system. The name of this system can be shortened or abbreviated to SI, from the French name Système International d'unités.

The International System of Units is a system of measurement based on 7 base units: the metre (length), kilogram (mass), second (time), ampere (electric current), kelvin (temperature), mole (quantity), and candela (brightness). These base units can be used in combination with each other. This creates SI derived units, which can be used to describe other quantities, such as volume, energy, pressure, and velocity.

The system is used almost globally. Only Myanmar, Liberia, and the United States do not use SI as their official system of measurement. In these countries, though, SI is commonly used in science and medicine.
History and use 
The metric system was created in France after the French Revolution in 1789. The original system only had two standard units, the kilogram and the metre. The metric system became popular amongst scientists.

In the 1860s, James Clerk Maxwell and William Thomson (later known as Lord Kelvin) suggested a system with three base units – length, mass, and time. Other units would be derived from those three base units. Later, this suggestion would be used to create the centimetre-gram-second system of units (CGS), which used the centimetre as the base unit for length, the gram as the base unit for mass, and the second as the base unit for time. It also added the dyne as the base unit for force and the erg as the base unit for energy.

As scientists studied electricity and magnetism, they realized other base units were needed to describe these subjects. By the middle of the 20th century, many different versions of the metric system were being used. This was very confusing.
In 1954, the 9th General Conference on Weights and Measures (CGPM) created the first version of the International System of Units. The six base units that they used were the metre, kilogram, second, ampere, Kelvin, and candela. The seventh base unit, the mole, was added in 1971.

SI is now used almost everywhere in the world, except in the United States, Liberia and Myanmar, where the older imperial units are still widely used. Other countries, most of them historically related to the British Empire, are slowly replacing the old imperial system with the metric system or using both systems at the same time.

Units of measurement

Base units 

The SI base units are measurements used by scientists and other people around the world. All the other units can be written by combining these seven base units in different ways. These other units are called "derived units".
{| class="wikitable floatleft" style="margin:1em auto 1em auto"
|+ SI base units
|-
!Unitname
!Unitsymbol
!Dimensionsymbol
!Quantityname
!Definition
|-
!second
|style="text-align:center" |s
|style="text-align:center" |T
|time
|
 Prior:  of a day of 24 hours of 60 minutes of 60 seconds
 Interim (1956):  of the tropical year for 1900 January 0 at 12 hours ephemeris time.
 Current (1967): The duration of  periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom.
|-
!metre
|style="text-align:center" |m
|style="text-align:center" |L
|length
|
 Prior (1793):  of the meridian through Paris between the North Pole and the Equator.FG
 Interim (1960):  wavelengths in a vacuum of the radiation corresponding to the transition between the 2p and 5d quantum levels of the krypton-86 atom.
 Current (1983): The distance travelled by light in vacuum in  second.
|-
!kilogram
|style="text-align:center" |kg
|style="text-align:center" |M
|mass
|
|mass
|
 Prior (1793): The grave was defined as being the mass (then called weight) of one litre of pure water at its freezing point.FG
 Interim (1889): The mass of a small squat cylinder of ~47 cubic centimetres of platinum-iridium alloy kept in the International Bureau of Weights and Measures, Paris, France.
 Current (2019): The kilogram is defined by setting the Planck constant h exactly to  (), given the definitions of the metre and the second. Then the formula would be 1 kg = 
|-
!ampere
|style="text-align:center" |A
|style="text-align:center" |I
|electric current
|
 Prior (1881): A tenth of the electromagnetic CGS unit of current. The [CGS] electromagnetic unit of current is that current, flowing in an arc 1 cm long of a circle 1 cm in radius, that creates a field of one oersted at the centre. IEC
Interim (1946): The constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 m apart in vacuum, would produce between these conductors a force equal to  newtons per metre of length.
 Current (2019): The flow of  times the elementary charge e per second.
|-
!kelvin
|style="text-align:center" |K
|style="text-align:center" |Θ
|thermodynamictemperature
|
 Prior (1743): The centigrade scale is obtained by assigning 0 °C to the freezing point of water and 100 °C to the boiling point of water.
 Interim (1954): The triple point of water (0.01 °C) defined to be exactly 273.16 K.
 Previous (1967):  of the thermodynamic temperature of the triple point of water.
 Current (2019): The kelvin is defined by setting the fixed numerical value of the Boltzmann constant k to , (J = kg⋅m2⋅s−2), given the definition of the kilogram, the metre and the second.
|-
!mole
|style="text-align:center" |mol
|style="text-align:center" |N
|amount ofsubstance
|
 Prior (1900): A stoichiometric quantity which is the equivalent mass in grams of Avogadro's number of molecules of a substance.ICAW
 Interim (1967): The amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon-12.
 Current (2019): The amount of substance of exactly  elementary entities. This number is the fixed numerical value of the Avogadro constant, NA, when expressed in the unit mol−1 and is called the Avogadro number.
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!candela
|style="text-align:center" |cd
|style="text-align:center" |J
|luminousintensity
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Prior (1946): The value of the new candle (early name for the candela) is such that the brightness of the full radiator at the temperature of solidification of platinum is 60 new candles per square centimetre.
 Current (1979): The luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency  hertz and that has a radiant intensity in that direction of  watt per steradian.
Note: both old and new definitions are approximately the luminous intensity of a whale blubber candle burning modestly bright, in the late 19th century called a "candlepower" or a "candle".
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Notes
The Prior definitions of the various base units in the above table were made by the following authorities:
 FG = French Government
 IEC = International Electrotechnical Commission
 ICAW = International Committee on Atomic Weights
All other definitions result from resolutions by either CGPM or the CIPM and are catalogued in the SI Brochure.
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Derived units 
Derived units are created by combining the base units. The base units can be divided, multiplied, or raised to powers. Some derived units have special names. Usually these were created to make calculations simpler.

Prefixes 

Very large or very small measurements can be written using prefixes. Prefixes are added to the beginning of the unit to make a new unit. For example, the prefix kilo- means "1000" times the original unit and the prefix milli- means "0.001" times the original unit. So one kilometre is 1000 metres and one milligram is a 1000th of a gram.

References 

 
Systems
Lake Michigan is one of the five Great Lakes in North America. It has a surface area of . It is  wide. Lake Michigan is the 5th largest lake in the world.

Lake Michigan is surrounded by the U.S. states of Indiana, Illinois, Wisconsin, and Michigan. It is the only Great Lake that is not partly in Canada. The largest city on the shore of Lake Michigan is Chicago.

The earliest time that people lived near the lake was 800 CE. The word "Michigan" originally meant the lake itself. It is believed to come from the Ojibwa word mishigami meaning "great water".

The first person to reach the deepest part of Lake Michigan was J. Val Klump. Klump reached the bottom with a submarine as part of a 1985 research expedition.

Twelve million people live along Lake Michigan's shores. They are mainly in the Chicago and Milwaukee areas.

References

Other websites

Great Lakes
Lakes of the United States
A gas syringe is a tool used in a laboratory. It is used to collect a gas or to measure the volume of a gas.

Simple systems can be settled in the laboratory to collect gas or to compress it.  It is usually used to explain Gas Law.

Laboratory equipment
Measuring tools
In chemistry, a mixture is a substance that is made up of two or more simpler substances. These substances can be chemical elements or compounds. A mixture can be made of liquids, solids, or gases.

Characteristics
A mixture is not the same as a compound which is made of two or more atoms connected together. For instance, a mixture of the gases hydrogen and nitrogen contains hydrogen and nitrogen, not the compound ammonia which is made of hydrogen and nitrogen atoms.

A mixture where the different parts can be distinguished easily is called heterogenous, one where this is not the case is called homogeneous. A third form is called colloid.

If one substance in a mixture dissolves in the other, it is called a solution. For example, if sugar is put in water it forms a mixture, then dissolves to make a solution. If it does not dissolve, it would be called a suspension.
Solids can be mixtures also. Alloys are mixtures. Many kinds of soil and rock are mixtures of different minerals. Thus, a mixture is made of two or more elements and/or compounds which are not chemically combined.

Gallery

References

Chemistry
Language families are groups of languages that are related to each other because they come from a common older language. The languages in such a family are similar in their vocabulary or structure.

For example, French and Spanish both come from Latin. Latin was spoken a long time ago, and some of the people who spoke it started to speak different ways - for the word "good", one group started saying "bueno" while another group started saying "bon". Most words are said a little differently in Spanish and French, so the two are called different languages.

Most languages belong to a language family, but some languages do not. These languages are called language isolates.

There also are constructed languages, such as Esperanto. Constructed languages are made for different reasons: making a 'world language', for fun, for use in fiction, etc.

Major language families

By number of languages
Ethnologue 22 (2019) lists these language families as "major". Each has at least 1% of all languages on Earth:
Niger–Congo (1,542 languages) (21.7%)
Austronesian (1,257 languages) (17.7%)
Trans–New Guinea (482 languages) (6.8%)
Sino-Tibetan (455 languages) (6.4%)
Indo-European (448 languages) (6.3%)
Australian [dubious] (381 languages) (5.4%)
Afro-Asiatic (377 languages) (5.3%)
Nilo-Saharan [dubious] (206 languages) (2.9%)
Oto-Manguean (178 languages) (2.5%)
Austroasiatic (167 languages) (2.3%)
Tai–Kadai (91 languages) (1.3%)
Dravidian (86 languages) (1.2%)
Tupian (76 languages) (1.1%)

Glottolog 4.0 (2019) lists the following as the largest families, of 8494 languages:

 Atlantic–Congo (1,432 languages) 
 Austronesian (1,275 languages) 
 Indo-European (588 languages) 
 Sino-Tibetan (494 languages)
 Afro-Asiatic (373 languages)
 Nuclear Trans–New Guinea (314 languages) 
 Pama–Nyungan (248 languages)
 Oto-Manguean (180 languages)
 Austroasiatic (159 languages)
 Tai–Kadai (94 languages)
 Dravidian (81 languages)
 Arawakan (78 languages)
 Mande (75 languages)
 Tupian (71 languages)

 
Language-related lists
Chess is a board game for two players. It is played on a square board, made up of 64 smaller squares, with eight squares in each row and column. Each player starts with sixteen pieces: eight pawns, two knights, two bishops, two rooks, one queen and one king. The goal of the game is for each player to try and checkmate the king of the opponent. Checkmate is a threat ('check') to the opposing king which no move can stop. It ends the game.

During the game, the two opponents take turns to move one of their pieces to a different square of the board. One player ('White') has pieces of a light color; the other player ('Black') has pieces of a dark color. There are rules about how pieces move, and about taking the opponent's pieces off the board. The player with white pieces always makes the first move. Because of this, White has a small advantage, and wins more often than Black in tournament games.
Chess is popular and is often played in competitions called chess tournaments. It is enjoyed in many countries, and is a national hobby in Russia.

History 

Most historians agree that the game of chess was first played in northern India during the Gupta Empire in the 6th century AD. This early type of chess was known as Chaturanga, a Sanskrit word for the military. The Gupta chess pieces were divided, like their military, into the infantry, cavalry, elephants, and chariots. Over time, these pieces became the pawn, knight, bishop, and rook. The English words chess and check both come from the Persian word shāh meaning king.
The earliest written evidence of chess is found in three romances (epic stories) written in Sassanid Persia around 600AD. The game was known as chatrang or shatranj. When Persia was taken over by Muslims (633–644) the game spread to all parts of the Muslim world. Muslim traders carried the game to Russia and Western Europe. By the year 1000, it had spread all across Europe. In the 13th century, a Spanish manuscript called Libro de los Juegos described the games of shatranj (chess), backgammon, and dice.

The game changed greatly between about 1470 to 1495. The rules of the older game were changed in the West so that some pieces (queen, bishop) had more scope, piece development was faster, and the game was more exciting. The new game formed the basis of modern international chess. Chess historians consider this to be the most important change since the game's invention.
Rules 
The rules of chess are governed by the World Chess Federation, which is known by the initials FIDE, meaning Fédération Internationale des Échecs. The rules are in the section Laws of Chess of the FIDE Handbook. FIDE also give rules and guidelines for chess tournaments.

Setup 
Chess is played on a square board divided into eight rows of squares called ranks and eight columns called files, with a dark square in each player's lower left corner. There are 64 squares on a chess board. The colors of the squares are laid out in a checker (chequer) pattern with light and dark squares. To make speaking and writing about chess easy, each square has a name. Rank are numbered from 1 to 8, and each file is lettered from a to h. The letter assigned to a file comes before the number.
its ownbel, such as g1 or f5. The pieces are in white and black sets. The players are called White and Black, and at the start of a game each player has 16 pieces. The 16 pieces are one king, one queen, two rooks, two bishops, two knights and eight pawns.

Movement 

Definitions: vertical lines are files; horizontal lines are ranks; lines at 45° are diagonals.
Each piece has its own way of moving around the board. The X marks the squares where the piece can move.
 The knight is the only piece that can jump over another piece.
 No piece may move to a square occupied by a piece of the same color.
 All pieces capture the same way they move, except pawns.
The king (K for short) can move one square in any direction. The king may not move to any square where it is threatened by an opposing piece. However, the king can move to a square that is occupied by an opponent's piece and capture the piece, taking it off the board.
 The queen (Q) can move any distance in any direction on the ranks, files and diagonals.
 The rooks (R) move any distance on the ranks or files.
 The bishops (B) move diagonally on the board. Since a bishop can only move diagonally, it will always be on the same color square.
 The knights (Kt or N) move in an "L" shape. Each move must be either two squares along a rank and one square along a file, or two squares along a file and one square along a rank. It is the only piece that can jump over other pieces. Like the other pieces, it captures an opposing piece by landing on its square.
The pawns can only move up the board. On its first move a pawn may move either one or two squares forward. A pawn captures one square diagonally, not as it moves: see white circles on its diagram. In some situations, pawns can capture opponent's pawns in a special way called en passant, which means in passing in French (see below).
Capturing 
Most pieces capture as they move. If a piece lands on an opponent's piece, the opposing piece is taken off the board. There are three special cases:
 The king cannot be taken (see check and checkmate).
 No piece can be taken while castling (see below).
 Pawns take one square diagonally.

Check and checkmate 

If a move that attacks the opposing king is made, the king is said to be 'in check'. The player whose king is in check must make a move that escapes the check. A player can't move into check. The options when a player is in check are moving the king, capturing the threatening piece, or moving another piece between the threatening piece and the king.

To win the game one player must checkmate the other player. Checkmate happens when the other player's king is in check and there is no way to get out of check. The word checkmate is often shorted to "mate". Most games end with one of the players resigning (giving up) when their position is so bad that defeat seems inevitable.

Special moves
Special moves

Castling 

Once in every game, each king can make a special move, known as castling. When the king castles, it moves two squares to the left or right. When this happens, the rook is moved to stand on the opposite side of the King. Castling is only allowed if all of these rules are kept:p120
 Neither piece doing the castling may have been moved during the game.
 There must be no pieces between the squares the king and the rook.
 The king may not be currently in check. The king can't pass through any square attacked by the opponent as well. As with any move, castling is not allowed if it would place the king in check.

En passant 

En passant ('in passing' in French) is a special capture. It is only available when a pawn moves forward two squares past an opposing pawn on an adjacent file. The opposing pawn must be on the 5th rank from its own side. Then the opponent's pawn can capture the double-mover as if it had only moved one square forward. This option is open on the next move only.
For example, if the black pawn has just moved up two squares from g7 to g5, then the white pawn on f5 can take it by en passant on g6. The en passant rule was developed when pawns were allowed to make their double move. The rule made it more difficult for players to avoid pawn exchanges and blockade the position. It kept the game more open.

Promotion 
When a pawn moves to its eighth rank, it must be changed for a piece: a queen, rook, bishop, or knight of the same color (player's choice). Normally, the pawn is queened, but in some cases another piece is chosen to get an advantage. This is called 'under-promotion'.

Ways a game may end 
Checkmates are rare in competitive chess. The most common ends are decisions made by one or both players.
Wins 
 Checkmate. When a king is in check, and cannot get out of it.
 Resignation. A player may resign at any time, usually because their position is hopeless. A losing player is able to resign by placing their king on its side on the chessboard.
 Out of time. If player's clock time is over (exceeding the time control). Strictly speaking, this is not part of the rules of the game, but part of the rules of tournament and match chess where chess clocks are used.Chapter 8
 Forfeit: A player who cheats, doesn't follow the rules, or doesn't follow the rules of conduct for a tournament can be forfeited. Sometimes, both players are forfeited.