Aarushhh/wikipedia-simple-splitted huggingface dataset:
A lake (from Latin: lacus) is a large body of water (larger and deeper than a pond) within a body of land. As a lake is separated from the ocean, it is not a sea. Some lakes are very big, and people in the past sometimes called them seas. Lakes do not flow like rivers, but many have rivers flowing into and out of them.

Most lakes on the surface of the Earth are fresh water and most are in the Northern Hemisphere. More than 60% of the lakes of the world are in Canada. Finland is known as The Land of the Thousand Lakes (there are 187,888 lakes in Finland, of which 60,000 are large).

Many lakes are man-made reservoirs built to produce electricity, for recreation, or to use the water for irrigation or industry, or in houses.
If there are not rivers flowing out of the lake (see Endorheic basin), or they are few and small, the lake loses water only by evaporation or because the water flows through the soil pores. Where the water evaporates rapidly and the soil around the lake has a high salt level, as in very dry places, the water of the lake has a high concentration of salt and the lake is called a salt lake. Examples of salt lakes are the Great Salt Lake, the Caspian Sea, the Aral Sea, and the Dead Sea.

Largest lakes by continent
Africa - Lake Victoria, also the second largest freshwater lake on Earth. It is one of the Great Lakes of Africa.
 Antarctica - Lake Vostok.
 Asia - Lake Baikal is the largest lake that is completely in Asia. The Caspian Sea, the largest lake on Earth, is on the Europe-Asia border (an artificial border) and so both continents share this lake.
 Australia - Lake Eyre, that most of the time is without water; it takes water when it rains a lot.
 Europe - Lake Ladoga, followed by Lake Onega, both in northwestern Russia.
 North America - Lake Superior.
 South America - Lake Maracaibo but it is like a bay because it has a wide opening to sea. The largest freshwater lake of South America is Lake Titicaca, which is also the highest body of water on Earth at 3,821 m (12,507 ft) above sea level where boats can travel.
Notable lakes 
 The largest lake in the world by area is the Caspian Sea, with 394,299 km². The largest freshwater lake by area is Lake Superior (82,414 km²), part of the Great Lakes.
 The longest freshwater lake is Lake Tanganyika, with a length of about 660 km. Lake Baikal is the second longest (about 630 km from tip to tip).
 The deepest lake is Lake Baikal in Siberia, with a bottom at 1,637 m (5,371 ft). Lake Tanganyika (1,470 m) is the second deepest lake.
 The highest lake of the world is a small lake (pond) without a name on Ojos del Salado at 6,390 m (20,965 ft). But the highest navigable lake is Lake Titicaca in Peru and Bolivia at 3,812 m (12,507 ft).
 The lowest lake of the world is the Dead Sea, bordering Israel and Jordan at 418 m (1,371 ft) below sea level. It is also one of the lakes with highest salt concentration.
 Lake Enriquillo in Dominican Republic is the only saltwater lake in the world where crocodiles live.

Related pages
 List of lakes
 Salt lake

References 

 
Biomes
French can mean:

Something that is from or related to France
The French language
French people
French cuisine
French kiss
East is one of the 4 main directions on a compass (called cardinal directions). East is normally to the right on most maps. For example: Japan is east of China, which is itself east of Pakistan. When “The East” is described: it usually refers to the countries of Asia (especially from Pakistan eastwards like China and India). The sun and moon rise in the east.

Basic English 850 words
Compass directions
A tire is a ring of material that covers the rim of a wheel. Most road vehicles and many other vehicles use rubber tires. Tires help vehicles to move smoothly. Some metro trains and trams also use rubber tires on their steel wheels to provide better traction than the steel tires of other trains.

Tires need to be changed after their treads wear away. Driving with worn tires is very dangerous. It can cause the tire to explode and the driver to lose control.

Tires were made of leather for thousands of years, and of iron or steel for hundreds. Pneumatic tires were invented in the 1840s and again in the 1880s. They became commonplace early in the 20th century.
Construction
Tires are made of different types of rubber. Softer rubber is used in summer or when the tires need better traction, for example, in auto racing. Tires made of harder rubber are made for long lasting performance, like long-distance truck carriers. There are many different types of tires. They come in different sizes and have different tread patterns.  

There are many different sizes of tires. On car and truck tires, they are marked with 3 numbers and might look like: 225/60R16.  The first number is the width in millimeters of the tire at the widest point when it is mounted and inflated. The second number is the sidewall (side of the tire) height as a ratio or percentage of the width. The last number is the wheel diameter in inches.

Example
Tire size: 225/60R16
Tire width = 225mm
Sidewall height = 135mm (225 * .60 = 135)
Wheel diameter = 16 inches
Very large tires (for example, tires on big mining trucks) use different units. For example: 59/80R63. The first number is the width in inches of the tire. The second number is the sidewall height as a ratio of the width. The last number is the wheel diameter in inches.

Tire damage
Most tires today do not have a tube inside of them. There are grooves in the wheel that let the tire be popped into place and hold a lot of air pressure. If there is a crack in the tire, it will not be able to hold its air. Tire leaks are very common. The most common cause is a hole from a nail or screw. This can usually be fixed by patching the inside of the tire so that it can hold air again. If the hole is close to or in the side of the tire, it can not be fixed. This is because the sides of the tire flexes to support the weight of the vehicle. A patch will not be able to handle the stress.
Mud and snow tires 
Mud and Snow, (or M+S, or M&S), is a designation used by manufacturers for all-season and winter tires. Most are designed to provide improved performance under low temperature conditions, compared to summer tires. The tread compound is usually softer than that used in tires for summer conditions. This provides better grip on ice and snow, but wears more quickly at higher temperatures. Tires may have well above average numbers of sipes in the tread pattern to grip the ice. M&S relates to the percentage of tread void area. On four-wheel drive vehicles, M&S tires are often standard equipment.

References 

Auto parts
Polymers
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 7.5 billion in April 2017. Asia is the most populous continent, with its 4.3 billion inhabitants being 60% of the world population. The most populous country is China 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
 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 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

Snow
Snow
West is one of the 4 main directions on a compass. West is normally to the left on most maps. For example: (Germany is located to the west of Poland, which is itself located to the west of Lithuania). When “The West” is used in everyday speech: it usually refers to the nations of Europe (Especially from Croatia Westward) and its daughter states in the Americas and Australasia. The sun and moon also set in the west.

Basic English 850 words
Compass directions
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 -- 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

Science-related lists
A president is the leader and head of state of a country which is a republic. A president is usually elected directly through a vote by the citizens or indirectly by legislatures (parliaments) who were voted by the citizens and which represents them. 

Some presidents are both the head of state and head of government, such as the President of the United States. In other countries, such as the Republic of Ireland, the President has a ceremonial role while the Prime Minister is the leader of the government. In France, the President and Prime Minister both share executive powers.

A president could also be the title of the head of a large business, company or organization.

Electing a President 
Many republics have direct elections by citizens to elect a president. But some other republics do not. The President of the United States is elected by the electoral college. Some other republics choose a president this way. In some other republics, the parliament elects a president.
Countries that have a monarch as leader, are called monarchies. Some countries have neither a president  or a monarch as leader, such as the Vatican City which is ruled by a religious leader called a Pope.

Companies also have presidents. They are elected by the people who own part of the company. In some companies, the people who are workers for the company elect (vote for) their company president.

Power of a President 
The president of a country is not the same thing as a prime minister. A prime minister is part of a parliament, but a president is not. In some countries, (such as the United States or France), the president has more power and responsibility than anyone else. Such a president is often called the nation's chief executive. As chief executive, the president must take an active role in all phases of government. The republics where the president is both the head of state and head of government (and there is no prime minister) are called a presidential republics.
In other republics (such as India, Israel or the Republic of Ireland), to be president is more of an honor or a symbol, and the position has no real power. The real power in such republics is held by the prime minister, who is the head of government. In this kind of republics, the president is only the head of state, and are called parliamentary republics.

In some republics (such as France or Russia) both the president as the head of state, and the prime minister as the head of government, run the day-to-day affairs of the state, but often the president has more powers than the prime minister. Such republics are called semi-presidential republics. 

Most monarchies that have a king or queen as their monarch and head of state, have no president, but very few monarchies, such as the United Arab Emirates has a president who is the head of state, who by custom (but not by law) is always the emir (monarch) of Abu Dhabi, which  is de facto hereditary.
The American President is restricted by the written United States Constitution, which was written to make sure that the American executive never became as powerful as in the British system.  The British Prime Minister is part of both the Legislature and Executive, whereas the American President is the head of the Executive. The American governmental system shows a clear separation of powers unlike the British system.
         
 All the president's ministerial appointments have to be vetted by Congress (Parliament) and Congress may have an opposition majority.
 The president does not have the ability to introduce and influence legislation in the same way as the British prime minister.
 Congress has much greater control over the budget and foreign policy than the British Parliament.
 There are broad areas of American life, such as education, crime and punishment, over which the president has virtually no influence at all.
 The president even has very limited control over the economy.
So despite having a large nuclear arsenal, the American president can not carry out policy and introduce legislation as freely as the British prime minister.

Related pages
 Head of state
 Monarch

Other websites 
 Presidents of the United States

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

Related pages 
 Web color

Lists
A list of lakes, ordered by continent:

Africa 

 International Lakes in Africa
 Lake Albert (Mobuto-Sese-Seko)
 Lake Chad
 Lake Edward
 Lake Kariba
 Lake Kivu
 Lake Mweru
 Lake Nyasa (Lake Malawi)
 Lake Tanganyika
 Lake Victoria
 in Democratic Republic of the Congo (Zaire)
 Lake Mai-Ndombe (Lake Leopold II)
 Lake Tshangalele
 Lake Tumba
 in Egypt
 Lake Mariout
 in Ethiopia
 Lake Abaya
 Lake Chew Bahir (Lake Stefanie)
 Lake T'ana
 in Ghana
 Lake Volta
 in Kenya
 Lake Baringo
 Lake Bogoria
 Lake Elmenteita
 Lake Magadi
 Lake Naivasha
 Lake Nakuru
 Lake Turkana (Lake Rudolf or Rudolph)
 in Malawi
 Lake Chilwa
 in Mozambique
 Cabora Bassa Lake
 in Nigeria
 Kainji Lake
 in Tanzania
 Lake Burigi
 Lake Eyasi
 Lake Ikimba
 Lake Jipe
 Lake Kitangiri
 Lake Manyara
 Lake Mdutu
 Lake Natron
 Nyumba ya Mumgu Reservoir
 Lake Rukwa
 Lake Sagara
 in Uganda
 Lake Bisina
 Lake George
 Lake Kyoga
 Lake Kwania
 in Zambia
 Lake Mweru Wantipa
 Lake Bangweulu

Antarctica 
 Lake Vida

Asia
Asia 

 International Lakes in Asia
 Aral Sea
 Caspian Sea
 Dead Sea
 in Cambodia
 Tonlé Sap Lake
 in China ( See also Lakes in China)
 Lake Daze Co
 Lake Dongting
 Poyang Lake
 Lake Tianchi
 Lake Dian
 Lake Qinghai
 Lake Taihu
 West Lake
 Xuanwu Lake
 in Israel
 Sea of Galilee (Lake Tiberias, Yam Kinneret)
 Lake Agmon
 Lake Ram
 Swamps Cabara
 in Kazakhstan
 Lake Balkhash
 Lake Zaysan
 in Kyrgyzstan
 Issyk Kul
 in Nepal
 Lake Rara
 in Russia (see also "in Russia" under #Europe, List of lakes in Russia)
 Lake Baikal (Lake Baykal)
 Lake Teletskoye
 in Taiwan
 Sun Moon Lake
 in Turkey
 Lake Van

Eurasia

Azerbaijan

Europe
International Lakes in Europe
 Lake Geneva (France, Switzerland; Lac Léman or Lac de Genève)
 Lake Constance (Austria, Germany, Switzerland; Bodensee)
 Lake Peipus (Estonia, Russia)
 Lake Ohrid (Albania, Macedonia)
 Lake of Lugano (Switzerland, Italy)
 Lake Maggiore (Switzerland, Italy; Lago Maggiore)
 Lake Ferto/Lake Neusiedler (Austria, Hungary; Neusiedlersee)
 Lake Big Prespa (Albania, Macedonia, Greece)
 Lake Small Prespa (Albania, Macedonia, Greece)
 Lake Vistytis (Lithuania, Russia)
 in Albania (see also: List of Albanian lakes)
 Lake Shkodër
 Lake Pogradec
 Lakes of Lure
 Lakes of Belsh
 in Austria
 Lake Attersee
 Lake Klopeiner
 Lake Wörther
 in Finland
 Lake Haukivesi
 Lake Inarinjärvi
 Lake Kallavesi
 Lake Keitele
 Lake Oulujärvi
 Lake Pielinen
 Lake Pihlajavesi
 Lake Päijänne
 Lake Saimaa
 in France
 Lake Annecy (lac d'Annecy)
 Lac de Serre-Ponçon
 Lake of Bourget
 Lac d'Aiguebelette
 Lac de Paladru
 Lac d'Orient
 in Germany
 Ammersee
 Arendsee
 Aussenalster
 Baldeneysee
 Bederkesaer See
Bederkesaer See
 Binnenalster
 Brahmsee
 Bullensee
 Chiemsee
 Dümmer
 Fleesensee
 Gothensee
 Halterner See
 Kellersee
 Kellersee
 Lake Constance (Bodensee)
 Maschsee
 Müggelsee
 Müritz
 Odertalsperre
 Okertalsperre
 Pfaffenteich
 Plauer See
 Plöner See
 Scharmützelsee
 Schmollensee
 Schweriner See
 Starnberger See
 Steinhuder Meer
 Tegeler See
 Wannsee
 Wolgastsee
 Zwischenahner Meer
 in Hungary
 Lake Balaton
 in Ireland (see also List of Irish lochs and loughs)
 Lough Allen
 Lough Conn
 Lough Derg (two lakes)
 Lough Erne (two lakes)
 Lough Mask
 Lough Neagh
 Lough Oughter
 Lough Owel
 Lough Ree
 Lough Rynn
 in Italy
 Lake Bracciano (Lago di Bracciano)
 Lake Bolsena (Lago di Bolsena)
 Lake Como (Lago di Como)
 Lake Garda (Lago di Garda)
 Lake Trasimeno (Lago Trasimeno)
 in Latvia
 Lake Burtnieks
 in Netherlands
 IJsselmeer
 Ketelmeer
 Veluwemeer
 in Poland
 Lake Dabie (Jezioro Dabie in Szczecin)
 Lake Mamry (Jezioro Mamry in Mazury lake district)
 Lake Sniardwy (Jezioro Sniardwy in Mazury lake district)
in Russia (see also "in Russia" under #Asia, List of lakes in Russia)
 Lake Ladoga
 Lake Onega (Onega, Onezhskoe ozero, Onezhskoe)
 Lake Pskov
 in Slovenia
 Lake Bled (Blejsko jezero)
 Lake Bohinj (Bohinjsko jezero)
 Cerkni?ko jezero
 ?martinsko jezero
 Lakes of Triglav (Triglavska jezera)
 in Sweden
 Lake Roxen
 Vänern
 Vättern
 in Switzerland (see also List of lakes of Switzerland)
 Lake Neuchâtel
 Lake Lucerne
 Lake Zürich
 in the United Kingdom (see also List of Scottish lochs, List of lakes in the Lake District)
 Bala Lake
 Buttermere
 Coniston Water
 Derwentwater
 Grasmere
 Gwernan Lake
 Kielder Water (Northumberland, England)
 Loch Awe/Etive
 Loch Lomond
 Loch Maree
 Loch Morar
 Loch Ness
 Loch Shin
 Loch Tay
 Tal-y-llyn
 Thirlmere
 Ullswater
 Windermere

North America
International Lakes in North America
 Lake Champlain
 Lake Erie †
 Lake Huron †
 Lake Nicaragua (Lake Cocibolca)
 Lake Ontario †
 Lake St Clair
 Lake Superior †
 Lake of the Woods
 in Canada
 Lake Abitibi
 Lake Athabasca
 Berg Lake
 Great Bear Lake
 Great Slave Lake
 Lake Louise
 Manicouagan Reservoir
 Lake Manitoba
 Moraine Lake
 Lake Nipigon
 Reindeer Lake
 Lac Saint-Jean
 Lac Saint-Louis
 Smallwood Reservoir
 Lake Simcoe
 Lake Winnipeg
 Sproat Lake
 Lake Winnipegosis
 in the United States of America
 Beaver Lake
 Lake Bemidji
 Caddo Lake
 Canandaigua Lake
 Cass Lake
 Cayuga Lake
 Chargoggagoggmanchauggagoggchaubunagungamaugg
 Crater Lake
 Detroit Lake
 East Okoboji Lake
 Great Salt Lake
 Indian Lake (Ohio)
 Lake George
 Lake Hopatcong
 Lake Itasca
 Keuka Lake
 Lake Kickapoo
 Lacamas Lake
 Lake Mead
 Lake Michigan †
 Mono Lake
 Lake Pontchartrain
 Portage Lake
 Salton Sea
 Lake Sammamish
 Seneca Lake
 Spirit Lake
 Lake Tahoe
 Town Lake
 Lake Travis
 Tug Lake
 Utah Lake
 Lake Washington
 West Okoboji Lake
West Okoboji Lake
 Lake Winnipesaukee
 Lake Winnebago
† = the North American Great Lakes

Oceania 
 in Australia
 
 in Indonesia
 Lake Toba (on Sumatra)
 In New Zealand (minor lakes not listed)
 In the North Island
 Mount Ruapehu's Crater Lake on Mount Ruapehu
 Lake Rotorua
 Lake Taupo
 Lake Waikaremoana
 Lake Wairarapa
 In the South Island
 Lake Aviemore
 Lake Benmore
 Lake Brunner
 Lake Coleridge
 Lake Ellesmere
 Lake Hauroko
 Lake Hawea
 Lake Manapouri
 Lake Monowai
 Lake Ohau
 Lake Rotoiti
 Lake Rotoroa
 Lake Sumner
 Lake Tekapo
 Lake Waitaki
 Lake Wakatipu
 Lake Wanaka
 Lake Te Anau

(Not yet classified by country:)
 Dead Lake

South America 

 International Lakes in South America
 Lake Titicaca

Former lakes

 Tulare Lake
 Lop Nur

Fictional lakes 
 Lake Evendim
 Lake Mithrim
 Lake Wobegon
Galileo Galilei (15 February 1564 – 8 January 1642) was an Italian polymath. Galileo was originally going to be a doctor but became a tutor instead. He was a professor of mathematics and natural science in Padua and Pisa. People most remembered him today for his conflict with the Catholic Church of his day, which led to his trial for heresy by the Inquisition.

Life 

Galileo was born on 15 February 1564 in Pisa, Duchy of Florence. He was the eldest of five siblings. His father was Vincenzo Galilei, who was a scholar and a musician.  In 1574, the Galilei family moved to Florence and he started his formal education in the Camaldolese monastery.
Astronomy 
Some people believe that Galileo was the first person to build a telescope. This is not true, but he was the first person to publish his observations of astronomical objects through a telescope. He discovered that the Milky Way is made of many stars. He discovered that the Moon has hills. He discovered the first moons not counting our own moon, these are the four biggest moons of Jupiter: Io, Europa, Ganymade and Callisto. Those moons are now called the Galilean moons. He discovered sunspots, which are dark areas of the Sun. He saw that the planet Venus has light and dark phases just like the Moon. This helped people to know that the Sun is at the center of the Solar System, as Nicolaus Copernicus had said.
Physics 
Galileo worked more at physics than at astronomy. He studied natural forces, and was one of the most important discoverers of the part of physics that is now called kinematics, including the discovery of the kinematic principle of relativity. However, he is often remembered now for things that either did not happen, or failed.

A legend says that he climbed the Leaning Tower of Pisa, and dropped cannonballs of different weights, to see which would strike the ground first. Even though their weights were not the same, they hit the ground at the same time. Galileo found that objects fall to the ground at the same rate, unless things like wind resistance change the rate. This went against the views of Aristotle, an ancient philosopher whose theory was different. Galileo's findings were ignored by most people, and Aristotle's view was still accepted as correct until Isaac Newton proved Galileo was right. This also led to Newton creating his Law of Gravity.
Publications 
The most important are:
 Siderius nuncius (starry messenger). Venice 1610. Discovery of 'new worlds' with the telescope.
 Dialogo sopra i due massimi sistemi del mondo, Tolemaico et Copernicano. Florence, 1632. The famous 'dialogue between two world systems, Ptolemaic and Copernican'.
 Discorsi et demonstrazioni mathematiche, intorno a due nuove scienze. (discourses and mathematical demonstrations relating to two new sciences) Leiden 1638. This, on kinematics, a non controversial subject, was written when Galileo was under house arrest, and published in Holland, out of the Inquisition's territory.

Trial for heresy
Trial for heresy 

Galileo came to accept the findings of Copernicus, that the Sun was the center of the then-known universe, and not the Earth. Because he promoted this and other ideas, he came to the notice of the Committee of Propaganda, the dreaded Inquisition. The Church taught that the Earth stood still, while everything in the sky moved around it. The Inquisition ruled in 1616 that other theories could only be discussed as possibilities, not facts. Galileo said he would obey. He played a major part in the scientific revolution through this argument.
Galileo later discussed the question in his most famous work, Dialogue Concerning the Two Chief World Systems, published in 1632 by permission of the Inquisition. His scientific writing was usually in Latin for hundreds of scientists around Europe, but this was one of the books he wrote in Italian so thousands of Italians could read it. The book was in the form of conversations between three men. The man representing the Church's point of view was called 'Simplicio'.
Church leaders who liked his earlier books were angry at this one. The Inquisition took action in 1633. He was arrested and put on trial. They found him "vehemently suspect of heresy". They reminded him of the fate of Giordano Bruno, who had been burnt at the stake for heresy on topics such as transubstantiation and the Trinity. Bruno also believed the Earth went round the Sun and stars had planets. The Inquisition forced Galileo to recant (say he was wrong) under the threat of execution, and to withdraw his works from publication. Galileo spent the last ten years of his life under house arrest. Galileo continued to write about physics and other topics, but not astronomy.

Galileo has become synonymous with a warrior for scientific truth. Although he had to retract his writings at his trial, it is widely believed that after the trial he insisted that Earth does move around the sun, saying the famous phrase "Eppur si muove''' – still it moves.'' The saying itself became a slogan for science.
Death 
Galileo Galilei died on  in Arcetri, Grand Duchy of Tuscany, Italy.

Previously, he was buried in a small room next to the novices' chapel at the end of a corridor. Later, he was reburied in the main body of the basilica in 1737 after a monument had been built there in his honor.

Related pages 
 Giordano Bruno
 Nicolaus Copernicus
 Johannes Kepler
 List of science books of 17th century
 Speed of light
 Michelson–Morley experiment

Notes

References

Bibliography 

 
 

1564 births
1642 deaths
Italian astronomers
People from Pisa
Italian physicists
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
Treaty

Basic English 850 words
When a person agrees to do something or to not do something, that person is making a promise. A promise can be made verbally (by saying it), or it can be written down as a contract. Breaking a promise, or not keeping it, is often just bad manners, but it can sometimes be illegal, such as when a contract is not kept.

A vow is a special promise.  It is mostly used in a religious sense or in ceremonies such as marriages when the couple who are being married make their "marriage vows", promising to be faithful to one another.

An oath is a promise in the legal sense.  When someone has to give evidence in a court of law they "swear an oath".  This means that they promise they will tell the truth.

Ethics
Law
A cloud is water vapour in the atmosphere (sky) that has condensed into very small water droplets or ice crystals that appear in visible shapes or formations above the ground.

Water on the Earth evaporates (turns into an invisible gas) and rises up into the sky. Higher up where the air is colder, the water condenses: it changes from a gas to drops of water or crystals of ice. We see these drops of water as clouds. The drops fall back down to earth as rain, and then the water evaporates again. This is called the "water cycle".

The atmosphere always has some water vapour. Clouds form when the atmosphere can no longer hold all the invisible air vapor. Any more water vapor condenses into very small water drops.

Warm air holds more water vapor than cool air. So if warm air with lots of water inside cools, it can form a cloud. These are ways air can cool enough to form clouds:
when air close to the ground is heated by the sun and rises to where the air is colder.
 along weather fronts warmer air is cooled as it runs into colder air;
 when air goes up the side of a mountain it cools as it goes higher;
 when warm air goes over something colder (such as cool water in a lake) or ground that is cooled at night it cools.

Clouds are heavy. The water in a cloud can have a mass of several million tons. Every cubic metre (m3) of the cloud has only about 5 grams of water in it. Cloud droplets are also about 1000 times heavier than evaporated water, so they are much heavier than air. They do not fall, but stay in the air, because there is warm air all round the heavier water droplets. When water changes from gas to droplets, this makes heat. Because the droplets are very small, they "stick" to the warm air.

Sometimes, clouds appear to be brilliant colors at sunrise or sunset. This is due to dust particles in the air.
Cloud classification 
Clouds are classified according to how they look and how high the base of the cloud is in the sky. This system was suggested in 1803.  There are different sorts of clouds because the air where they form can be still or moving forward or up and down at different speeds.  Very thick clouds with large enough water droplets can make rain or snow, and the biggest clouds can make thunder and lightning.

There are five basic families of clouds based on how they look:

 Cirrus clouds are high and thin.  The air is very cold at high levels, so these clouds are made of ice crystals instead of water droplets.  Cirrus clouds are sometimes called mares' tails because they look like the tails of a horse.

 Stratus clouds are like flat sheets.  They may be low-level clouds (stratus), medium-level (altostratus), high-level (cirrostratus), or thick multi-level clouds that make rain or snow (nimbostratus).
Stratocumulus clouds are in the form of rolls or ripples.  They may be low-level clouds (stratocumulus), medium-level (altocumulus), or high-level (cirrocumulus).

 Cumulus clouds are puffly and small when they first form.  They may grow into heap clouds that have moderate vertical extent (nothing added to the name), or become towering vertical clouds (towering cumulus).

 Cumulonimbus clouds are very large cumulus-type clouds that usually develop cirrus tops and sometimes other features that give them their own unique look.

The following is a summary of the main cloud types arranged by how high they form:

High-Level clouds 

High clouds form from  in cold places,  in mild regions and  in the very hot tropics.  They are too high and thin to produce rain or snow.

High-level clouds include:

 Cirrus (Ci)
 Cirrocumulus (Cc)
 Cirrostratus (Cs)

Medium-level clouds
Middle clouds usually form at  in colder areas. However, they may form as high as  in the tropics where it's very warm all year.  Middle clouds are usually made of water droplets but may also have some ice crystals.  They occasionally produce rain or snow that usually evaporates before reaching the ground.

Medium-level clouds include:

 Altocumulus (Ac)
 Altostratus (As)

Low-level clouds 

Low-level clouds are usually seen from near ground level to as high as .  Low clouds are usually made of water droplets and may occasionally produce very light rain, drizzle, or snow.

Low-level clouds include:
 Stratocumulus (Sc)
 Stratus (St)

When very low stratus cloud touches the ground, it is called fog.

Moderate-vertical clouds
These are clouds of medium thickness that can form anywhere from near ground level to as high as .  Medium-level cumulus does not have alto added to its name.  The tops of these clouds are usually not much higher than .  Vertical clouds often create rain and snow.  They are made mostly of water droplets, but when they push up through cold higher levels they may also have ice crystals.

Moderate-vertical clouds include:

 Cumulus (Cu)
 Nimbostratus (Ns)

Towering-vertical clouds 

These clouds are very tall with tops usually higher than .  They can create heavy rain and snow showers.  Cumulonimbus, the biggest clouds of all, can also produce thunderstorms.  These clouds are mostly made of water droplets, but the tops of very large cumulonimbus clouds are often made mostly of ice crystals.

Towering-vertical clouds include:

 Towering cumulus (Tcu)
 Cumulonimbus (Cb)

Gallery

As a sign 
In the Bible, clouds are often a sign of God's presence.

References

Other websites

More reading
More reading
 

Basic English 850 words
The water cycle (or hydrological cycle) is the cycle that water goes through on Earth.

Water is essential for life as we know it. It is present throughout the Solar System, and was part of the Earth from its formation. The source of the water was the same as the source of the Earth's rock: the cloud particles which condensed in the origin of the Solar System.
Processes
This is the process that water starts and ends in the water cycle.
 The cycle starts when water on the surface of the Earth evaporates. Evaporation means the sun heats the water which turns into a gas.
 Then, water collects 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.

Humans activities that affect the water cycle
Human activities that change the water cycle include:
 Agriculture
 Industry
 Building dams
 Deforestation
 Removing groundwater from wells
 Taking water from rivers
Related pages 
 Carbon cycle
 Rock cycle
 Drought
 Ecohydrology
 Flood
 Hydrosphere
 Rain
 Bioprecipitation
 Water

References 

cycle
Weather
Earth sciences
Water vapor is water that is in the form of a vapor, or gas. It is a part of the water cycle. When liquid water is heated to boiling point, 100 degrees Celsius (212 F), it turns into vapor. Water vapor can also be produced directly from ice; this is called sublimation. Steam is water vapor, but clouds are liquid water. The amount of water vapor in air is called humidity and it affects weather conditions. In the cold, breathing out causes the water vapor in the breath to freeze.

Water vapor weighs less than air, thus slightly reduces the lift produced by an aircraft wing.

Water vapour is transparent. The small droplets that look white like mist are actually liquid.

Water vapour is a big cause of the greenhouse effect.

Water vapor is invisible but when it condenses it makes visible water.

Thermodynamics
Vapor
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 

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 valuable 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
Minerals 

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 

Basic English 850 words
States of matter
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

Materials science
Gases
A contract is an agreement or promise that the law can enforce. The law will enforce some agreements but not others. For example, in most places, if a parent promises to take a child to get ice cream, the law will not enforce that promise as a legal contract.

The legal rules about which promises are enforced by the law can be different in different places (or jurisdictions), but a contract is usually enforced only if it is made by people or groups who want it to be enforced and who know what they are doing.

Sometimes, a contract is written down and signed by the people agreeing to it, but it does not always need to be. People usually sign a contract when something important or costly is being done. For example, when people take a job, they will sometimes sign a contract with their employers. The contract will show what the person must do as part of his job, how much they will be paid, and so on. The person and the employer will sign the contract, and it will become a legal promise.
If someone breaks a contract, another person might sue him or her. In a lawsuit about a contract, the court will look at the contract, listen to what the people who made the contract say about it, and then make a decision about what the contract means.

Related pages
 Law 
 Oath
Documents

Business law
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.

Basic English 850 words
Kolkata (spelled Calcutta before 1 January 2001) is the capital city of the Indian state of West Bengal. It is the second largest city in India after Mumbai. It is on the east bank of the River Hooghly. When it is called Calcutta, it includes the suburbs. This makes it the third largest city of India. This also makes it the world's 8th largest metropolitan area as defined by the United Nations. Kolkata served as the capital of India during the British Raj until 1911. Kolkata was once the center of industry and education. However, it has witnessed political violence and economic problems since 1954. Since 2000, Kolkata has grown due to economic growth. Like other metropolitan cities in India, Kolkata struggles with poverty, pollution and traffic congestion.

History
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. Calcutta became the capital of British India in 1772,
. However, the capital shifted to the hilly town of Shimla during the summer months every year, starting from the year 1864.  Richard Wellesley, the Governor General between 1797 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

Former national capitals
A pencil is a kind of writing equipment that is also used to draw, usually on paper. Most pencil cores are made of graphite powder mixed with a clay binder. So, a pencil is usually made with a piece of graphite mixed with clay that has a wood case around it. The shape is usually a hexagonal prism but some pencils are square or cylinder.

Colored pencils are a kind that do not use greyish silver graphite. Instead, the core is colorful. Colored pencils or crayons are usually meant for drawing rather than writing.

The difference between pens and pencils 
The important difference between pens and pencils is that the tip of a pencil is made of solid graphite (or other material) which is rubbed off onto the paper.  A pen has a tip, usually made of metal, with liquid ink coming out and onto the paper.  Writing with a pen can smudge when it is still wet.  Writing from a pencil can be erased, but writing from a pen usually cannot, unless it uses a special type of ink and eraser.
History 
 An early writing tool was the reed pen used by ancient Egyptians, who wrote with ink on sheets of papyrus paper. 

Another early writing instrument was the stylus, which was a thin stick of wood or metal, often lead. It was used for scratching onto black wax that covered white wood, a method used by the Romans. The word pencil comes from the Latin word  which means "little tail". It is an invention of the 16th century in England.
Discovery of graphite deposits 
Some time before 1565 (it may have been as early as 1500), a large deposit of graphite was found in Borrowdale, Cumbria. The locals found that it was very useful for marking sheep. This deposit of graphite was extremely pure and solid, and it could easily be sawn into sticks. This is still the only large scale deposit of graphite ever found in this solid form. Chemistry was in its early stages and the substance was thought to be a form of lead. Consequently, it was called plumbago (Latin for "lead ore"). The black core of pencils is still  referred to as lead, even though it never had the element lead.
The value of graphite was soon realized, mainly because it could be used to line the moulds for cannonballs. The mines were taken over by the Crown and guarded. When enough stocks of graphite had been added up, the mines were flooded to prevent theft until more was needed. Graphite had to be sneakily moved out for use in pencils. Because graphite is soft, it requires some form of holder. Graphite sticks were at first wrapped in string or in sheepskin for stability. The news of the usefulness of these early pencils spread far and wide, attracting the attention of artists all over the known world. 

England continued to have a monopoly on the production of pencils until a method of reconstituting the graphite powder was found. The distinctively square English pencils continued to be made with sticks cut from natural graphite into the 1860s. The town of Keswick, near the original findings of block graphite, has a pencil museum.