open-index/open-wikipedia-markdown huggingface dataset:
Oboe

An **oboe** is a woodwind instrument with a double reed. It looks very similar to the clarinet, and may be confused with it. While the clarinet's shape remains cylindrical, the oboe's body is conical. The sounds produced by clarinets and oboes are very different. An oboe's sound is produced by blowing air through the double reed at the upper end of the instrument which forces the two reeds to vibrate together which produces the sound. The oboe has four parts: the bell, lower joint, upper joint, and the reed. A person that plays the oboe is called an oboist. A typical orchestra employs between two and four oboists, one of which also plays the cor anglais which sounds a fifth lower than the oboe. The oboe is part of a family of double reed instruments that includes the piccolo oboe, oboe d'amore, Cor anglais, bass oboe, and heckelphone. 

The oboe came from the shawm which was a medieval and Renaissance instrument. It became popular in the Baroque period. Bach and Handel both used it in most of their orchestral music. Many Italian composers such as Antonio Vivaldi wrote concertos for the instrument, and it is used in a lot of chamber music. At this time it hardly had any keys, but over time more keys were added which made it easier to play the sharps and flats.

Later composers to write for the oboe as a solo instrument include Mozart, Weber, Richard Strauss, Vaughan Williams and Francis Poulenc.

The principal oboist in an orchestra plays the pitch A (440Hz) for the rest of the orchestra to tune their instruments to before a performance.

The name *oboe* comes from the French language *hautbois*, meaning "high wood", a high-pitched woodwind instrument.
GURPS

The **Generic Universal RolePlaying System**, or **GURPS**, is a role-playing game system created by Steve Jackson Games. It emphasizes a set of rules that can be used in any time or world.  Characters are created using a point-based system.  There have been four releases of the GURPS core rules and dozens of game supplements that extend the core rules with genre or setting-specific information. 

In 1990, GURPS became the focus of a Secret Service investigation when an as yet unreleased GURPS Cyberpunk game supplement was misconstrued by the Secret service as being a handbook for computer crime.
Eric Idle

**Eric Idle** (born 29 March 1943) is an English actor, comedian, composer, musician, singer-songwriter and writer. He is one of the members of Monty Python. Monty Python is a British comedy team.

Idle was born in South Shields, County Durham. He studied English at Pembroke College, Cambridge.

He is known for his songwriting and singing skills. His songs were important parts of the Monty Python television programme and movies. He wrote the song "Always Look on the Bright Side of Life". This song was written as the closing song of the 1979 movie Life of Brian.

He lives in Studio City, California.

## Other websites 
*
Enemy

An **enemy** is a  or group of people who is against another person or group. In war, the enemy is anyone fighting for the other side of the war.

In the Bible, Saint Peter states that: ' your enemy, the Devil, roams around like a roaring lion looking for someone to devour' (1 Peter 5:8)
Adelaide

**Adelaide** () is a city in Australia. It is the capital city of the state of South Australia, and it has an approximate population of 1.2 million people.

It is the fifth biggest city in Australia, behind Sydney, Melbourne, Brisbane and Perth. Adelaide was founded in 1836 by Colonel William Light, who named it after Queen Adelaide.

Adelaide is near the Southern Ocean and is north of the Fleurieu Peninsula. It has a river going through it called the River Torrens. Many festivals are held there. Adelaide has a hot-summer and cool-wet-winter Mediterranean climate. Grapes for wine production are grown in the Barossa Valley about 50 kilometres (30 miles) northeast of Adelaide, in the McLaren Vale about 30 kilometres south of Adelaide and parts of the Mt Lofty Ranges to the east.

## References
## Other websites 
* Adelaide Airport
Market

]]

A **market** is a place where  go to buy or sell things. When people have products to sell, they set up a **market place**. There may be a special building for the market place, or the market may be held in an open space where the sellers can put up a stall (like a kind of tent) and then take the stall down at the end of the day.

The word **"**market" can also have a more general meaning in the economy. It can mean the way things are bought or sold. "There is a big market for dishwashers" means that lots of people want to buy dishwashers. Therefore, a business that makes dishwashers is likely to be able to make a lot of money. When things are sold, people buy the product, and this "stimulates the economy" (helps people to spend and earn money). The market needs to balance supply and demand. There is no reason to make a supply of dishwashers if people do not want dishwashers. In the market, prices may change quickly if supply or demand changes.

## Competition 
If a seller of a good cannot supply what customers want or asks for a very high price, other sellers may try to supply that good. If other sellers enter the market for that good, in competition, that will tend to fulfill demands and lower prices. Sellers who do not like competition may try to kill their competition. When there is no competition, a monopoly is formed. Many countries have laws to protect the free market from monopolies.

## Related pages 
* Market forms
* Shop
French

**French** can mean:

*Something that is from or related to France
**The French language
**French people
**French cuisine
*French kiss
Yoshi

**Yoshi** is a fictional dinosaur who appears in the *Mario* series of video games made by Nintendo. The character was created by Shigeru Miyamoto. 

Yoshi's best-known ability is his ability to eat enemies. He has a long tongue which he uses to eat enemies and items. In some games, after Yoshi eats enemies, they can be turned into eggs, which can be thrown. One of Yoshi's companions is Mario who helps Yoshi throughout dangerous situations. Most of the time, Mario can ride Yoshi. 

Yoshi also can jump very high, and can also float in the air a little bit by kicking his legs. He can also ground pound enemies by quickly jumping on them.

Yoshis are usually green, but can come in many other colors. These other colors include green, red, light blue, blue, purple, pink, yellow, orange, brown, black, and white. Blue Yoshi is especially in Super Mario World. In *Super Mario 64 DS*, Rec Room there's a light blue color in one of Yoshi's minigames Tox Box. In Vs Mode multiplayer, it has a dark blue color and the third player can play him.

In a few games like *Super Mario World* Yoshi gains powers, like flying, shooting fireballs when spat out, ground pounding, or all three by holding certain colored koopa troopa shells in its mouth.

Yoshi first appeared in the game *Super Mario World* (SNES), which was released in 1990 in Japan and 1991 in the US and EU.

## Yoshi series
* Yoshi (video game)
* Yoshi's Cookie
* Yoshi's Safari
* Super Mario World 2: Yoshi's Island
* Yoshi's Story
* Yoshi's Universal Gravitation/Topsy Turvy
* Yoshi Touch & Go
* Yoshi's Island DS
* Yoshi's New Island
* Yoshi's Woolly World
* Yoshi's Crafted World

## Other appearances
**Mario Kart 64* (N64)
**Mario Kart: Super Circuit* (GBA)
*Mario Kart DS (DS)
**Mario Kart Wii* (Wii)
**Mario Kart 7* (3DS)
**Mario Kart 8* (Deluxe) (Wii U/Switch)
**Mario Party* series (N64, GCN, DS, and Wii)
*Super Mario 64 DS (DS) (Vs Mode multiplayer only, the one with the game card is Green Yoshi, others are Red, Blue, and Yellow Yoshi.
**Super Mario Kart* (SNES)
**Super Mario Sunshine* (GCN)
**Super Smash Bros.* (N64)
**Super Smash Bros. Melee* (GCN)
**Mario Kart: Double Dash!!* (GCN)
**Mario Power Tennis* (GCN)
**Super Mario Strikers* (Wii)
**Super Mario World* (SNES)
*''Yoshi's Island* (SNES), (GBA)
**Yoshi's Island DS* (DS)
**Yoshi Touch & Go* (DS)
**Yoshi Topsy-Turvy* (GBA)
**Yoshi's Story* (N64)
**Yoshi's Woolly World* (Wii U/3DS)
**Yoshi's Crafted World* (Switch)
**Mario Strikers Charged* (Wii)
**Super Smash Bros. Brawl* (Wii)
**Super Mario Galaxy 2* (Wii)
**New Super Mario Bros. U* (Wii U)
**Super Mario Maker* (Wii U/3DS)
**Super Mario Maker 2* (Switch)

## Reception
Yoshi is a very well-known character in the *Mario'' series. Yoshi is also seen a lot in Mario toys, games, and shirts. Yoshi was in two of the McDonald's Happy Meal Mario toy promotions, which only starred Mario, Donkey Kong and Yoshi himself. In a 2008 poll, Yoshi was voted as the third favorite video game character in Japan. Cloud Strife and Mario were second and first place, in that order.

## References
Population

in 1994]]
A **population** is the number of living people that live together in the same place. A city's population is the number of people living in that city. These people are called **inhabitants** or **residents**. The population includes all individuals that live in that certain area. The world population was estimated to have reached 8 billion in November 2022. Asia is the most populous continent, with its 4.8 billion inhabitants being 60% of the world population. The most populous country is India with 1.4 billion people.

Population density is the average number of people in a place. Urban areas such as big cities have a high population density. People living there lives close to each other. In areas with a low population density, people usually live far away from each other, such as in rural areas out in the countryside.

Usually population refers to the number of humans in a certain area. The maximum population that can be supported in an area is called the carrying capacity.

## Population trends 
Global population is going up, but the population growth rate is declining all over the world. Growth in poor countries is faster than in rich ones; some rich countries have a population pyramid that is nearly square. Urbanization is also common, and urban areas usually have lower birth rates. In population growth, births exceed deaths. In the modern world this is due to reduction of infant deaths, control of infectious diseases, and improved agriculture so more people can eat.

The change in population from 2010 to 2015 was:
* World: +420 million
* Africa: +146 million
* Asia: +223 million
* Europe: +3 million
* Latin America and Caribbean: +35 million
* Northern America: +14 million
* Oceania: +2.9 million

Human population control is the practice of altering the rate of growth of a human population. Concerns about overpopulation and its effects on poverty, environmental degradation, and political stability led to efforts to reduce population growth rates.

## Related pages 
* Population density
* Population growth
* Human population planning
* Overpopulation
* Census

## References 
## Further reading 
* 
* Henderson, Kirsten, and Michel Loreau. "An ecological theory of changing human population dynamics." People and Nature 1.1 (2019): 31-43.
* YAN Kun(2011). The tendency equation of the population and its limit value in the United Kingdom (Brief annotation of the connection equation(R)), Xi'an: Xi'an Modern Nonlinear Science Applying Institute.
Snow

s covered with snow]]

**Snow** is a form of ice. Snow forms when water in the atmosphere becomes frozen. It comprises individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. Snow comes in all different shapes and sizes.

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.

## References
World war

infantry supported by a M18 tank destroyer advancing through an enemy-occupied town during World War II, the most recent conflict to widely be considered a "world war".]]
A **world war** is an international conflict in which most of the countries in the world fight or help. 

There have been two World Wars so far, World War I (1914-1918), and World War II (1939-1945),  Several earlier historical wars such as the Anglo-Dutch Wars were fought in many places around the world, but they were wars amongst European empires.

After World War II, many people were scared that  World War III would start from the Cold War between the United States and Western Bloc on one side and the Soviet Union and Eastern Bloc on the other.  After World War II, countries had many powerful weapons, including jet bomber airplanes, which could carry nuclear weapons to destroy many buildings and kill many people instantly, far away; and much faster missiles which could also carry nuclear weapons.
List of colors

* This is a **list of colors** that have articles about them on the Simple English Wikipedia.

## Related pages 
* Web color
List of physics topics

## A
Air resistance

## C
Compression --Critical angle -- Colour filter -- Concave lens -- Convex lens

## D
Diffraction -- Density (distance)--(displacement)

## E
Electromagnetic spectrum -- Energy --

## F
Fluid friction -- Focus -- Force sensor -- Frequency -- Friction --
Flotation

## G
Gamma ray -- Gravity

## I
Inertia -- Interference

## K
Kinetic energy
## L
Lamp-housing -- Laser pointer -- Lens -- Longitudinal wave -- Longitudinal wave model (Crova's disc) --

## M
Moment of inertia

## N
 -- Normal force -- Newton's laws of motion

## O
Oscilloscope - Overhead projector

## P
Plane mirror -- Potential energy -- Prism

## R
Rarefaction -- Ray box -- Reflection -- Refraction -- Ripple tank  --
relative density refleaction of light through prism

## S
Signal generator -- Slinky -- Slit plate -- Spring -- String theory -- Sound -- Statistical mechanics

## T
Tension -- Translucent screen -- Transverse wave -- Transverse wave model --

## V
Vibration -- Velocity

## W
wave -- Wave speed -- Waveform -- Wavefront -- Wavelength --

## Y
Young's double-slit experiment
Agreement

is often used to mean that there is an agreement.]]
An **agreement** is writing down a promise made. Agreements are common in law and business. For example, when a person takes out a loan or hires someone to work, an agreement is usually signed so that everyone understands what and when things must be done.

## References
## Related pages
*Contract
*Treaty
Promise

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  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.
Water cycle

The **water cycle**, or hydrological cycle, is the cycle that water goes through on Earth.

## Overview
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.

## Processes
This is the process that water starts and ends in the water cycle.

* The cycle starts when water underground of the Earth evaporates. Evaporation means the sun heats the water which turns into a gas
* Then, water gathers as water vapour in the sky. This makes clouds
* Next, the water in the clouds gets cold. This makes it become liquid again. This process is called condensation
* Then, the water falls from the sky as rain, snow, sleet or hail. This is called precipitation
* The water sinks into the surface and also collects into lakes, oceans, or aquifers. It evaporates again and continues the cycle
* This whole process in which water evaporate and falls on the land and later flows back in river and pond is known as water cycle

## Human activities affecting water cycle
* Industry
* Agriculture
* Deforestation
* Dam construction
* Removing groundwater from wells
* Taking water from rivers

## Related pages
* Rock cycle
* Geophysics
* Hydrosphere
* Carbon cycle
* Coriolis effect
* Ecohydrology

## References
Evaporation

**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.

## Differences between evaporation and boiling 
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.

## Rate of evaporation 
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.

## Related pages
* Boiling

## References
Contract

or promise between two or more people.]]
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  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.

## Related pages
* Law 
* Oath
Face

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. It is also known as city of joy It has 4,500,000 (4.5 million) people living in it. 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.

## History 
.]]
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.  Richard Wellesley, the Governor General between 1797 and 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.

## References 
## Other websites
Solid

**Solid** is one of the four common states of matter. The molecules in solids are closely bound together, so 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. 

Solids can resist forces applied to their surface. 

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.

## Kinds of solids 
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.

### Metals 
's Chrysler Building, the world's tallest steel-supported brick building.]]

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.

Since metals are good conductors of electricity, they are  in electrical tools and for carrying an electric current over long distances with little energy loss. Because of this, electrical power grids rely on metal cables to get electricity. Home electrical systems, for example, are wired with copper for its good conducting uses. The high thermal conductivity of most metals also makes them useful for stovetop cooking utensils.

### Minerals 
s.]]

Minerals are natural solids formed through many geological processes and having a crystal structure with uniform physical things throughout..

## Related pages
*Liquid
*Gas
*Plasma

## Other websites 
*
Parliament

, London]]

A **parliament** is a type of legislature. 

The most famous parliament is probably the Parliament of the United Kingdom, which is sometimes called the "Mother of all Parliaments".  The word "parliament" comes from the French word *parler*, which means a talk. 

The Althing, the national parliament of Iceland, was founded earlier (930 AD), so it is the oldest legislature in the world still existing. However, the Althing did not function as a legislature for four centuries, and its role as a *primary* legislature is modern. 

## Other parliaments 
Other parliaments have copied the UK and work similarly. They have three levels - a lower house which makes the law, an upper house which reviews the law (Decides if they like it or not, and suggest changes to it), and a head of state who is mostly for show and who starts and ends each year of parliament. The Prime Minister is almost always the person whose party has the most seats, but if the lower house does not think he is doing a good job they can call a vote of no confidence and ask him to leave his job as Prime Minister or have an election.

## The word "parliament" 
Sometimes people use the word "parliament" to describe a legislature, even if it is not a real parliament. A "parliament" is a type of legislature which has a Prime Minister.

## Similar to a congress 
A parliament is a lot like a congress but a congress cannot ask the head of the government to leave his job. Also, a congress runs for a number of years according to the country's constitution, but a parliament can be stopped as long as enough members agree. Elections are held after this happens.

## Countries that have Parliaments 
* Australia
* Austria
* Belgium
* Canada
* Ghana
* Germany
* Greece
* Iceland
* India
* Israel
* Italy
* Malaysia
* Moldova
* Netherlands
* New Zealand
* Pakistan
* Romania
* Russia
* Ukraine
* United Kingdom
* Bulgaria

## Related pages
*Constitution
*Constitutional economics
*Democracy
*Legal rights

## References
Turing test

The **Turing test** is a test to see if a computer can interact with a person. The human should not be able to realize it is interacting with a computer. 

Alan Turing thought that if a human could not tell the difference between another human and the computer, then the computer had shown intelligent behavior.

## Test setup 
A person has a telegraph, and is connected to two communication partners. One of the two correspondents is a machine. The person can ask anything with the telegraph. If the person cannot tell which of the two is the machine more than 50% of the time, then the machine is said to be *intelligent*.

Later on, people narrowed down the test. A human is unlikely to know everything. Therefore, both the human and the machine would be specialists in some field of knowledge (and so would the person asking).

## Media 
The comic strip Dilbert makes several mentions to the PHB (Pointy Haired Boss) failing the Turing test.

## Related pages 
*AlphaGo

## References 
## Other websites
*
Fuel

A **fuel** is a substance that is changed in some way to produce heat, electricity, or other forms of energy. This is usually by being burnt in fire, although there are exceptions, such as nuclear fuel. Fuel can be divided into two main types: fossil fuels and other fuels.

## Fossil fuel 
There are several kinds of fossil fuels:
* coal
* oil and products that are refined from oil (gasoline, diesel, kerosene)
* natural gas
Some people do not want us to use fossil fuels because they may pollute the environment. Because all fossil fuels are made out of carbon, burning them makes carbon monoxide and carbon dioxide. Too much carbon dioxide in the air causes a greenhouse effect. Carbon monoxide in the air is poisonous to humans and animals. Fossil fuels are also non-renewable, or renew extremely slowly (thousands to hundreds of millions of years). This means that we will eventually run out of fossil fuels.

## Other fuels 
Other fuels are not made from fossils. Some of these, like nuclear and hydrogen, do not have carbon in them. Others, like wood or ethanol, do have carbon in them. Some examples of these fuels are:
* Nuclear fuel (uranium, plutonium, thorium, etc.)
* Hydrogen
* Biofuels from biomass
** Firewood
** Biodiesel (a diesel-type fuel made from plants)
** Ethanol (made from grains or other plants)
These fuels are renewable. This means that we can make more of them if we run out. For instance, if we run out of ethanol, we can grow some more corn and make some more ethanol.

## Other websites 
* Fuel -Citizendium
Latvia

**Latvia** (Latvian: *Latvija*), officially the **Republic of Latvia** (*Latvijas Republika*), is a country in Northern Europe. The capital is Riga. It is one of the Baltic states, together with Estonia in the north and Lithuania in the south. Latvia's neighbours to the east are the countries Russia and Belarus. Latvia is divided into four parts: Kurzeme, Vidzeme, Zemgale, and Latgale.

People from Latvia are called Latvians. They speak the Latvian language, which is a little like the Lithuanian language but is not close enough to be understood. There are other peoples that live in Latvia, including the Germans and the Russians.

## History 
Latvia was settled by the Baltic tribes thousands of years ago. They mainly fished, hunted, and traded.

German traders and crusaders came to Latvia at the end of the 12th century. Latvians lost control of their homeland. Over the next 800 years, Germans, Danes, Swedes, Poles, and Russians all invaded Latvia. Latvia finally became independent in 1918.

Between the 13th and the 15th centuries, the Teutonic Knights had a state that occupied Latvian territory.

Before World War I, the aristocracy was mainly German.

During the Great Northern War from 1700 to 1721, what is now Latvia became the part of the Russian Empire and were organized as Courland and Livonia.

Latvian workers took part in the revolutionary struggle in 1905. 

In 1940, Latvia was annexed by the Soviet Union. It was briefly under German occupation during World War II in from 1941 to 1944. 

After the war, many factories were opened. Latvia became one of the more successful Soviet republics.

In 1991 the Soviet Union collapsed, and Latvia had its independence restored.

## Politics  
In Copenhagen on 13 December 2002, Latvia and nine other countries were invited to join the European Union. On 20 September 2003, Latvians held an election to vote on joining. Two thirds of Latvians voted to join, and on 1 May 2004, Latvia became a member of the EU.

Latvia has been a NATO member since 29 March 2004.

There are 43 local government units, set up in 2020. 36 are municipalities (Latvian: *novadi*) and 7 state cities. Before 2020 there were 110 municipalities and nine republic cities.

## International rankings 
## Related pages
* Latvia at the Olympics
* Latvia national football team
* List of rivers of Latvia

## References 
## Other websites 
* Latvian Government official site
Malta

**Malta** is a country in Southern Europe, and a member of the European Union. It is an island near the center of the Mediterranean Sea, south of Sicily.  Although it is geologically located on the African Plate, Malta is recognized as a European country. The capital of Malta is Valletta. Around 500,000 people live in Malta and it is one of the most densely populated countries in the world. Malta is 316 sq km, which makes it one of the smallest countries and the smallest in the European Union. Its many cities and towns grew close to each other over time.

## Language 
Maltese is the national language of Malta. It is a Semitic language similar to the Maghrebi Dialects of North Africa, with a high amount of influence from Romance languages, in particular Italian, and more recently English. Maltese and English are the official languages in line with the constitution of the country. A majority of the people of Malta can speak three languages; Maltese, English and Italian.

## Money 
Malta had its own currency, called the Maltese Lira until 2008. The Maltese *Lira* was better known as the Maltese *Pound* because of the strong links to the United Kingdom. One Maltese Lira consisted of 100 *cents*. In 2008 Malta joined the Euro countries in adopting the Euro as the National Currency.

## History 
People have lived in Malta since at least 5200 BC. The island has some key archaeological sites dating from early times.

Malta became well known as the base of the Knights Hospitaller. They moved to Malta after being forced to leave Palestine and then Rhodes, in Greece. In 1565 they survived a great attack by the Ottoman Empire. The history of the knights at Malta continued the strong Roman Catholic beliefs in the country that were started by the Norman and Spanish rulers.

In 1798, Napoleon took control of Malta. The French rule was not popular and in 1800 Maltese rebels invited the British Royal Navy to come to the island. This led to 200 years as a British colony and independent Commonwealth member.

During World War II, Malta was attacked this time by the Axis forces. The entire island was symbolically given the George Cross for heroism.

Malta became independent in 1964 and a republic in 1974. In 2004 Malta joined the European Union and in 2008 Malta joined the Euro.

## Notes
## Other websites 
* Maltese Relocation and Travel Guide
* Malta travel guide and information 
* Malta Wiki - Malta Popular Encyclopedia 
* Malta holidays and hotels 
* Malta travel guide
* Malta 
* Malta Travel Guide
Index of Soviet Union–related articles

## Lists of people 
*List of Premiers of the Soviet Union
*List of Russians

## A 
* AK-47

## B 
* Baltic states
* Bolshevik

## C 
* Central Asia
* Cold War
* Constructivism
* Communism
* Communist Party of the Soviet Union
* Comrade
* Collective farming
** Collectivisation in the USSR

## E 
* Eastern Front (World War II)

## G 
* Glasnost
* Great Soviet Encyclopedia

## H 
* Hero of the Soviet Union
* History of the Jews in  Russia and Soviet Union
* History of the Soviet Union (1985-1991)
* Holodomor

## K 
* Kolkhoz

## M 
* Marxism–Leninism
* Moscow Metro

## O 
* October Revolution

## P 
* Palace of Soviets

## R 
* Red Army
* Republics of the Soviet Union
* Russian Civil War

## S 
* Socialism
* Soviet
* Soviet (council)
* Soviet people
* Soviet Union
* Soviet Union national bandy team
* Soviet Union national football team
* Soviet Union national ice hockey team
* Sputnik programme
* State Anthem of the Soviet Union

## V 
* Volga Germans

## W 
* Warsaw Pact Organization
* White movement
* World War I
* World War II
Shaanxi

**Shaanxi** (Chinese:陕西, also sometimes called **Shenshi**) is a province in northwest China. The word "Shaan" (viz Shanzhou) is a place in Henan Province. "Xi" means "west". So "Shaanxi" means "the place to the west of Shaan". 

Although in pinyin, "Shaanxi" is spelled exactly the same as "Shanxi", the only difference in how the two words are pronounced is that the first syllable in "Shanxi" is said using the first tone in Mandarin, while the first syllable in "Shaanxi" is said with the third tone. Since tone markers are not usually used to show how to pronounce the two different names, the first word in "Shaanxi" is spelled using the Gwoyeu Romatzyh method instead, which indicates tones by adding extra letters to a syllable.

The river Wei He runs across it. It has a large population of more than 30 million people. The capital of Shaanxi is Xi'an. It abbreviates as **Shan** (陕) or **Qin** (秦), also known as **SanQin** (三秦, meaning *Three Qins*).

## History 
January 23, 1556 – A massive earthquake, measuring 9.0 on the Richter scale, strikes Shaanxi, killing over 850,000 people. This is the most devastating earthquake in recorded history.

## Political divisions 
Shaanxi Province is divided into ten municipalities:

# Xi'an Municipality(西安市)
# Ankang Municipality(安康市)
# Baoji Municipality(宝鸡市)
# Hanzhong Municipality(汉中市)
# Shangluo Municipality(商洛市)
# Tongchuan Municipality(铜川市)
# Weinan Municipality(渭南市)
# Xianyang Municipality(咸阳市)
# Yan'an Municipality(延安市)
# Yulin Municipality(榆林市)
Surfing

**Surfing** is a water sport done in the ocean or sea. The surfer uses their surfboard to catch a wave and ride in towards the shore.

Surfing was invented by the Polynesians at least 4000 years ago. Surfing made its Olympic debut at the 2020 Summer Olympics in Tokyo, Japan. It has become a popular sport among both men and women of all ages. With lifestyles and regimens freer than those of most sports, surfers comprise a unique culture. Though surfing is practiced in many other Pacific nations, its center remains Hawaii, where many rounds of the international surfing championships (the ASP) are held annually. Surfing is popular in Australia, the US, and Northern Europe.

File:Oahu North Shore surfing hand drag.jpg|A surfer in Oahu.
File:Sufer carrying surfboard along the beach.JPG|A surfer carrying his *surfboard*.
File:Surfing in Hawaii.jpg|A man surfing.
File:Oahu North Shore surfing catching wave.jpg|Surfers catching a wave.

## Related pages
*Skimboarding
*Windsurfing
Lyon

**Lyon** (Arpitan: *Liyon*) is a city in the southeast of France. It is the third-largest city in the country (behind Paris and Marseille), with about 520,774 people living there in 2022. It is the second largest *metropolis*, or metro area, in France (behind only that of Paris), with 2,327,861 people in 2022. 

In ancient history, the name of Lyon was *Lugdunum*. Someone who lives in Lyon is called a *Lyonnais* (male) or a *Lyonnaise* (female) in French.

Lyon has a humid subtropical climate (*Cfa* in the Koeppen climate classification). It is between the Rhône and the Saône. It is about  west of the Italian border. 

The central part of Lyon, located on the peninsula between the Rhône and the Saône, was named a World Heritage Site by UNESCO.

## Famous people from Lyon 
* The Lumière Brothers who created cinema
* Paul Bocuse, a world renowned chef

## Sports 
Famous sports clubs from Lyon are:

* Olympique Lyonnais: The local football team that plays in Ligue 1
* ASVEL: The local basketball team
* LOU: (Lyon Olympique Universitaire) The local rugby team

## Education 
* École Centrale de Lyon
* École pour l'informatique et les nouvelles technologies
* École pour l'informatique et les techniques avancées
* École spéciale de mécanique et électricité
* EMLYON Business School
* E-Artsup
* Institut Polytechnique des Sciences Avancées
* Institut supérieur européen de gestion group
* Institut supérieur européen de formation par l'action
* Sup'Biotech
* Web@cademie

## References
## Other websites
Lisbon

**Lisbon** () is the capital city of Portugal. It is the largest city of Portugal. The city has a population of about half million people. In Lisbon's urban area live around 2.8 million people, being the 10th-most populous urban area in the European Union. 
Lisbon is placed on the right bank (western) of the Tagus River, near the outfall. It has a pleasant climate and has about 220 days of sunshine each year. There are many beautiful beaches close to the city. There are also many seafood restaurants, historical sites and monuments, being one of the oldest cities in the world.

## Geography
### Civil parishes 
The municipality of Lisbon have 24 *freguesias* (civil parishes).

* Ajuda
* Alcântara
* Alvalade
* Areeiro
* Arroios
* Avenidas Novas
* Beato
* Belém
* Benfica
* Campo de Ourique
* Campolide
* Carnide
* Estrela
* Lumiar
* Marvila
* Misericórdia
* Olivais
* Parque das Nações
* Penha de França
* Santa Clara
* Santa Maria Maior
* Santo António
* São Domingos de Benfica
* São Vicente

## Transportation 
### Metro 
 is Portugal's oldest and largest subway system.]]
The Lisbon Metro connects the city centre to different districts, it also reaches some suburbs around the Lisbon metropolitan area, like Amadora and Loures.

### Trams 
 in Alfama.]]
Trams are a traditional public transport in Lisbon. It was first introduced in 1901, many of the electric trams were originally imported from the US, and were called *americanos*. Trams in Lisbon are coloured yellow and is one of the tourist icons of the city, and their size is great for steep hills and narrow streets of the central city.

## Related pages
*The tram derailment that killed 15, in September 2025

## References 
## Other websites 
* Official page of the city  
* Lisbon Photos  a collection of Photos, showing Lisbon as it is to visitors.
Organic compound

is one of the simplest organic compounds]]
**Organic compounds** are carbon-based compounds. Organic compounds contain carbon bonds in which at least one carbon atom is covalently linked to an atom of another type (usually hydrogen, oxygen or nitrogen). Most polymers are organic compounds.

## History 
The name "organic" is a historical name from the 19th century.

People believed that only living things could make organic compounds and "dead" things (such as minerals) could make inorganic compounds. However, Friedrich Wöhler proved this wrong by synthesizing urea, a well-known organic compound.

## Kinds of organic compounds 
There are natural organic compounds, and synthetic ones. Their structure may be described by using names, and making diagrams. 

One way of showing the molecule is by drawing its structural formula. Because molecules can have complicated structures, people have made ways to show them in simple language. One way is to use line diagrams. Each atom is shown by a letter, and connected by a line to each atom with which it is has a covalent bond. One line means a single bond, two lines means a double bond and so on. 

Because there is in an infinite number of possible organic compounds, language is needed to give a unique name to each one. The International Union of Pure and Applied Chemistry, or IUPAC, made a system for doing this. Although an IUPAC name makes every single possible molecule unique, the names are often long and complicated, so in everyday life, *trivial* names--unofficial but widely understood names--are used, such as the trivial names Paracetamol, Tylenol, and Acetaminophen, which are used for a compound whose IUPAC name is *N-(4-hydroxyphenyl) acetamide*. Some of these trivial names are trademarks.

### Natural compounds 
Natural compounds are compounds made by living beings. These could also be made in a lab, but many of these compounds are taken from nature because it is easier and less expensive to do it that way. For example, every year people grow and eat huge amounts of natural sugar and starch. Other common natural compounds are: amino acids, proteins, carbohydrates, many antibiotics like penicillin and amoxicillin.

### Synthetic compounds 
Synthetic compounds are those made by people. Sometimes, this is done by taking something natural and changing the molecule in a small way, such as making glycerin from vegetable oils. Other compounds are synthesized in long, complicated reactions with many steps. Plastics are sometimes mostly natural, and other kinds are manufactured.

## Structure 
Since a compound is often first discovered in nature instead of being made on purpose in a lab, people may know the compound exists, and even know what it does sometimes, but not know exactly what atoms it is made of and how it is arranged. There are several ways of taking an unknown compound and finding out this structure:
* Mass spectrometry
* X-ray diffraction
* Nuclear magnetic resonance spectroscopy
* Infrared spectroscopy

## Related pages 
*Acetone
*Inorganic compound
*Organic chemistry
*Biochemistry

## Other websites 
* Organic chemistry online
Comoving distance

In normal cosmology, '**comoving**' distance or '**proper distance**' is one of several distances measured by cosmologists to define distances between objects.  

## Method 
To talk about the shape of the Universe, scientists want to forget that the Universe is expanding. So they separate the shape from time and pretend that the Universe is not expanding. They remember that, really, the Universe is expanding, but they write this in a variable called the scale factor. Then, the distances they talk about, while putting the scale factor to the side, are called **comoving distances**. When they think about the Universe using comoving distance, they think of the Universe as not expanding. This way, some calculations are easier.

## Purpose 
When the part of the Universe which we can see today started, it was very small. Everything in this part of the Universe was much closer together than today. It was also very hot and photons (particles of light) were moving in different directions. Light moves very fast, but the light speed is limited and the Universe was expanding very fast.

### Comparison 
Think of two ants on the surface of an expanding balloon. One ant starts moving towards another, but the balloon itself is also expanding. After a long time the balloon starts expanding more slowly. Eventually one ant reaches another. That's like photons in our universe. Some of the light from the stars you see at night traveled for billions of years to reach your eye. Surprisingly, it started very close to where you were (or the atoms of which your body consists), but just could not keep up with the universe expansion. Of course, if something else started out very close to where you were, but was not traveling toward you, it would be very far away from you now because of the expansion.