Aarushhh/wikipedia-simple-splitted huggingface dataset:
Biology  is the science that studies life, living things, and the evolution of life. Living things include animals, plants, fungi (such as mushrooms), and microorganisms such as bacteria and archaea.

The term 'biology' is relatively modern. It was introduced in 1799 by a physician, Thomas Beddoes.

People who study biology are called biologists. Biology looks at how animals and other living things behave and work, and what they are like. Biology also studies how organisms react with each other and the environment. It has existed as a science for about 200 years, and before that it was called "natural history". Biology has many research fields and branches. Like all sciences, biology uses the scientific method. This means that biologists must be able to show evidence for their ideas and that other biologists must be able to test the ideas for themselves.

Biology attempts to answer questions such as:
"What are the characteristics of this living thing?" (comparative anatomy)
 "How do the parts work?" (physiology)
 "How should we group living things?" (classification, taxonomy)
 "What does this living thing do?" (behaviour, growth)
 "How does inheritance work?" (genetics)
 "What is the history of life?" (palaeontology)
 "How do living things relate to their environment?" (ecology)

Modern biology is influenced by evolution, which answers the question: "How has the living world come to be as it is?"

History
The word biology comes from the Greek word βίος (bios), "life", and the suffix -λογία (logia), "study of".
Branches
 Algalogy
 Anatomy
 Arachnology
 Bacteriology
 Biochemistry
 Biogeography
 Biophysics
 Botany
 Bryology
 Cell biology
 Cytology
 Dendrology
 Developmental biology
 Ecology
 Endocrinology
 Entomology
 Embryology
 Ethology
 Evolution / Evolutionary biology
 Genetics / Genomics
 Herpetology
 Histology
 Human biology / Anthropology / Primatology
 Ichthyology
 Limnology
 Mammalology
 Marine biology
 Microbiology / Bacteriology
 Molecular biology
 Morphology
 Mycology / Lichenology
 Ornithology
 Palaeontology
 Parasitology
 Phycology
 Phylogenetics
 Physiology
 Taxonomy
 Virology
 Zoology

References

 
Science-related lists
Botany is the study of plants. It is a science. It is a branch of biology, and is also called plant biology. It is sometimes called phytology. Scientists who study botany are called botanists. They study how plants work.

Branches of botany 
Agronomy—Application of plant science to crop production
Bryology—Mosses, liverworts, and hornworts
Forestry—Forest management and related studies
Horticulture—Cultivated plants
Micropaleontology—Pollen and spores
Mycology—Fungi
Paleobotany—Fossil plants
Phycology—Algae
Phytochemistry—Plant secondary chemistry and chemical processes
Phytopathology—Plant diseases
Plant anatomy—Cell and tissue structure
Plant ecology—Role of plants in the environment
Plant genetics—Genetic inheritance in plants
Plant morphology—Structure and life cycles
Plant physiology—Life functions of plants
Plant systematics—Classification and naming of plants
Recent trends 
University departments of botany are often now merged into a wider group of specialities, including cell biology, genetics, ecology, cytology, palaeontology and other topics. This gives students and research workers access to a wider education and a wider range of research techniques.
Notable botanists 
 Theophrastus, Hellenistic philosopher, wrote books, systematized botanical descriptions.
 Ibn al-Baitar (d. 1248), Andalusian-Arab scientist, author of one of the largest botanical encyclopedias.
 Georges-Louis Leclerc, Comte de Buffon (1707–1788) was a French naturalist, Intendant of the Jardin du Roi ('King's Garden'). Buffon published thirty-five volumes of his Histoire naturelle during his lifetime, and nine more volumes were published after his death.
Luther Burbank (1849–1926), American botanist, horticulturist, and a pioneer in agricultural science.
Charles Darwin (1809–1882) wrote eight important books on botany after he published the Origin of Species.
Al-Dinawari (828–896), Kurdish botanist, historian, geographer, astronomer, mathematician, and founder of Arabic botany.
Conrad Gessner (1516–1565) was a Swiss naturalist and bibliographer. 
Joseph Dalton Hooker (1817–1911), English botanist and explorer. Second winner of Darwin Medal.
Carl Linnaeus (1707–1778), Swedish botanist, physician and zoologist who laid the foundations for the modern scheme of Binomial nomenclature. He is known as the father of modern taxonomy, and is also considered one of the fathers of modern ecology.
Gregor Mendel (1822–1884), Augustinian priest and scientist, and is often called the father of genetics for his study of the inheritance of traits in pea plants.
Reid Venable Moran (1916–2010) was an American botanist and a curator  of the San Diego Natural History Museum. He wrote a document titled "Cneoridium dumosum (Nuttall) Hooker F. Collected March 26, 1960, at an Elevation of about 1450 Meters on Cerro Quemazón, 15 Miles South of Bahía de Los Angeles, Baja California, México, Apparently for a Southeastward Range Extension of Some 140 Miles".
John Ray (1627–1705) was an English naturalist, the father of English natural history.
G. Ledyard Stebbins (1906–2000) was an American botanist and geneticist. He was one of the leading evolutionary biologists of the 20th century.
Eduard Strasburger (1844–1912) was a Polish-German professor who was one of the most famous botanists of the 19th century.
Nikolai Vavilov (1887–1943) was a Russian botanist and geneticist. He  showed how and where crop plants evolved. He studied and improved wheat, corn, and other cereal crops.
References

Related pages 

 Botanical garden
Belgium (officially the Kingdom of Belgium; , , ) is a country in Western Europe. Its capital, Brussels, is the home of many organisations including the European Union and NATO. Belgium is bordered by The Netherlands in the north, Germany to the east, Luxembourg to the southeast and France to the south.

Belgium has an area of . Around 11.6 million people live in Belgium. It is a founding member of the European Union and is home to its headquarters.
Regions 
There are three regions in Belgium. The regions are mainly based on language and culture. Flanders and Wallonia are both split up into five provinces each.
 Flanders is the name of the northern half of Belgium, just south of the Netherlands. Most of the people in this region, called the Flemish people, speak Dutch.
 Wallonia is the name of the southern half of Belgium, just north of France. Here, most of the people, the Walloons, speak French. There is a small part of Wallonia next to the border with Germany where the people speak German.
 The Brussels-Capital Region, where the capital of Brussels is found, is in the middle of the country, but surrounded by Flanders on all sides. It used to be Dutch-speaking, but today French is mostly spoken, with some Dutch.
The population is about 60% Dutch-speaking, 39% French-speaking, and 1% German-speaking (the so-called Deutschbelgier). To look after all these groups, Belgium has a complex system of government with highly autonomous regions.

History
History

The name 'Belgium' comes from Gallia Belgica. This was a Roman province in the northernmost part of Gaul. Before Roman invasion in 100 BC, the Belgae, a mix of Celtic and Germanic peoples, lived there. The Germanic Frankish tribes during the 5th century brought the area under the rule of the Merovingian kings. A slow shift of power during the 8th century led the kingdom of the Franks to change into the Carolingian Empire. The Treaty of Verdun in 843 divided the region into Middle and West Francia. They were vassals either of the King of France or of the Holy Roman Emperor.
Many of these fiefdoms were united in the Burgundian Netherlands of the 14th and 15th centuries.

The Eighty Years' War (1568–1648) divided the Low Countries into the northern United Provinces and the Southern Netherlands. Southern Netherlands were ruled by the Spanish and the Austrian Habsburgs. This made up most of modern Belgium.
After the campaigns of 1794 in the French Revolutionary Wars, the Low Countries were added into the French First Republic. This ended Austrian rule in the area. Adding back the Low Countries formed the United Kingdom of the Netherlands. This happened at the end of the First French Empire in 1815.

The Belgian Revolution was in 1830. Leopold became king on  1831. This is now celebrated as Belgium's National Day.

The Berlin Conference of 1885 gave control of the Congo Free State to King Leopold II.  Millions of Congolese people were hurt or killed, mostly to make rubber, and Leopold became very wealthy.  In 1908 the Belgian state took control of the colony after  a scandal about the deaths.
Germany invaded Belgium in 1914. This was part of World War I.  The opening months of the war were very bad in Belgium.  During the war Belgium took over Ruanda-Urundi (modern-day Rwanda and Burundi).  After the War, the Prussian districts of Eupen and Malmedy were added into Belgium in 1925.  The country was again invaded by Germany in 1940 and under German control until 1944.  After World War II, the people made king Leopold III leave his throne in 1951.  This is because they thought he helped the Germans.  Belgium joined NATO as a founding member.

In 1960 the Belgian Congo stopped being under Belgian rule.  Two years later Ruanda-Urundi also became free.

Geography
Geography 

Belgium is next to France, Germany, Luxembourg and the Netherlands. Its total area is 34,143 square kilometers (including sea area). The land area alone is 30,689 km², of which 195 km² or 0.64% are inland and coastal waters. Belgium has three main geographical regions. The coastal plain is in the north-west. The central plateau are part of the Anglo-Belgian Basin. The Ardennes uplands are in the south-east. The Paris Basin reaches a small fourth area at Belgium's southernmost tip, Belgian Lorraine.

The coastal plain is mostly sand dunes and polders. Further inland is a smooth, slowly rising landscape. There are fertile valleys. The hills have many forests. The plateaus of the Ardennes are more rough and rocky. They have caves and small, narrow valleys. Signal de Botrange is the country's highest point at 694 metres (2,277 ft).
Regions
Belgium is divided into three regions: Flemish Region (Flanders), Walloon Region (Wallonia), and Brussels-Capital Region (Brussels Region or Brussels - also the name of the city):

¹ The city of Brussels does not lie in Flanders Region and therefore cannot be the largest city of this region.

² German name: Wallonie(n): the very eastern part of the Walloon Region is officially German-speaking, the so-called German-speaking Community of Belgium.

Provinces
Flanders and Wallonia are divided into provinces. Brussels (Region) is not part of any province.
{| class="sortable wikitable" style="text-align:left"
! style="width:110px;"| Province
! style="width:110px;"| Region
! style="width:110px;"| Dutch name
! style="width:110px;"| French name
! style="width:115px;"| Capital
! style="width:115px;"| Largest city
! style="width:50px;"| Area (km²) 
! style="width:70px;"| Population (2022) 
|-
| Antwerp || Flanders || Antwerpen || Anvers || Antwerp(Dutch: Antwerpen)(French: Anvers)|| Antwerp || style="text-align:right"|2,876|| style="text-align:right"|1,886,609
|-
| East Flanders || Flanders || Oost-Vlaanderen || Flandre-Orientale || Ghent(Dutch: Gent)(French: Gand) || Ghent || style="text-align:right"|3,007|| style="text-align:right"|1,543,865
|-
| Flemish Brabant || Flanders || Vlaams-Brabant || Brabant flamand || Leuven(French: Louvain) || Leuven || style="text-align:right"|2,118 || style="text-align:right"|1,173,440
|-
|-
| Hainaut || Wallonia || Henegouwen || Hainaut || Mons(Dutch: Bergen) || Charleroi || style="text-align:right"|3,813|| style="text-align:right"|1,351,127
|-
| Liège ¹ || Wallonia || Luik || Liège || Liège ¹(Dutch: Luik) || Liège || style="text-align:right"|3,857 || style="text-align:right"|1,110,989
|-
| Limburg || Flanders || Limburg || Limbourg || Hasselt || Hasselt || style="text-align:right"|2,427|| style="text-align:right"|885,951
|-
| Luxembourg || Wallonia || Luxemburg || Luxembourg || Arlon(Dutch: Aarlen)(Luxembourgish: Arel) || Bastogne(Dutch: Bastenaken) || style="text-align:right"|4,459|| style="text-align:right"|291,143
|-
| Namur || Wallonia || Namen || Namur || Namur(Dutch: Namen) || Namur || style="text-align:right"|3,675|| style="text-align:right"|499,454
|-
| Walloon Brabant || Wallonia || Waals-Brabant|| Brabant wallon || Wavre(Dutch: Waver) || Braine-l'Alleud(Dutch: Eigenbrakel) || style="text-align:right"|1,097|| style="text-align:right"|409,782
|-
|-
| West Flanders || Flanders || West-Vlaanderen || Flandre-Occidentale || Bruges(Dutch: Brugge) || Bruges || style="text-align:right"|3,197|| style="text-align:right"|1,209,011
|}
¹ German name: Lüttich - the very eastern part of the province of Liège is officially German-speaking, the so-called German-speaking Community of Belgium.

 Climate 
Belgium has a mostly oceanic climate, but the Belgian Ardennes has a continental climate. 

The highest temperature ever recorded in Belgium was , on 25 July 2019 in Begijnendijk. The lowest temperature ever recorded in Belgium was , on 20 January 1940 in Lesse.

 Politics 

Since 1993, Belgium is a federal state, divided into three regions and three communities.

Regions:
 Brussels-Capital Region
 Flemish Region (or Flanders)
 Walloon Region (or Wallonia)

Communities:
 Flemish Community
 French Community of Belgium
 German-speaking Community of Belgium

It has a system of government known as a constitutional monarchy, meaning that it has a monarch, but that the monarch does not rule the country, and that a government is elected democratically.
Belgium has had its own monarchy since 1831. King Albert II left the throne on July 21, 2013 and the current king is Philippe.

In Belgium, the government is elected. Between mid-2010 and late 2011, after no clear result in the election, Belgium had no official government, until Elio Di Rupo became Prime Minister. Flanders and Wallonia both also have their own regional governments, and there is a notable independence movement in Flanders. Alexander De Croo is currently the Prime Minister.

Military
The Belgian Armed Forces have about 46,000 active troops. In 2009 the yearly defence budget was $6 billion. There are four parts: Belgian Land Component, or the Army; Belgian Air Component, or the Air Force; Belgian Naval Component, or the Navy; Belgian Medical Component.

Science and technology
Adding to science and technology has happened throughout the country's history. cartographer Gerardus Mercator, anatomist Andreas Vesalius, herbalist Rembert Dodoens and mathematician Simon Stevin are among the most influential scientists.

Chemist Ernest Solvay and engineer Zenobe Gramme gave their names to the Solvay process and the Gramme dynamo in the 1860s. Bakelite was formed in 1907–1909 by Leo Baekeland. A major addition to science was also due to a Belgian, Georges Lemaître. He is the one who made the Big Bang theory of the start of the universe in 1927.

Three Nobel Prizes in Physiology or Medicine were awarded to Belgians: Jules Bordet in 1919, Corneille Heymans in 1938 and Albert Claude together with Christian De Duve in 1974.  Ilya Prigogine was awarded the Nobel Prize in Chemistry in 1977. Two Belgian mathematicians have been awarded the Fields Medal: Pierre Deligne in 1978 and Jean Bourgain in 1994. (Retrieved: November 10, 2011)
In February 2014, Belgium became the first country in the world to legalize euthanasia without any age limits.

Culture
Fine arts

There have been many additions to painting and architecture. Several examples of major architectural places in Belgium belong to UNESCO's World Heritage List. In the 15th century the religious paintings of Jan van Eyck and Rogier van der Weyden were important. The 16th century had more styles such as Peter Breughel's landscape paintings and Lambert Lombard's showing of the antique. The style of Peter Paul Rubens and Anthony van Dyck was strong in the early 17th century in the Southern Netherlands.
During the 19th and 20th centuries many original romantic, expressionist and surrealist Belgian painters started. These include James Ensor and other artists in the Les XX group, Constant Permeke, Paul Delvaux and René Magritte. The sculptor Panamarenko is still a remarkable figure in contemporary art. The artist Jan Fabre and the painter Luc Tuymans are other internationally known figures in contemporary art.

Belgian contributions to architecture were also in the 19th and 20th centuries. Victor Horta and Henry van de Velde were major starters of the Art Nouveau style.
Belgium has several well-known authors, including the poet Emile Verhaeren and novelists Hendrik Conscience, Georges Simenon, Suzanne Lilar and Amélie Nothomb. The poet and playwright Maurice Maeterlinck won the Nobel Prize in literature in 1911. The Adventures of Tintin by Hergé is the best known of Franco-Belgian comics. Many other major authors, including Peyo, André Franquin, Edgar P. Jacobs and Willy Vandersteen brought the Belgian cartoon strip industry a worldwide fame.

Belgian cinema has brought a number of mainly Flemish novels to life on-screen. Belgian directors include André Delvaux, Stijn Coninx, Luc and Jean-Pierre Dardenne. Well-known actors include Jan Decleir and Marie Gillain. Successful films include Man Bites Dog and The Alzheimer Affair''.

Cuisine
Cuisine

Belgium is famous for beer, chocolate, waffles and french fries. French fries were first made in Belgium. The national dishes are "steak and fries with salad", and "mussels with fries".
Other local fast food dishes include a Mitraillette. Brands of Belgian chocolate and pralines, like Côte d'Or, Guylian, Neuhaus, Leonidas, Corné and Galler are famous. Belgium makes over 1100 varieties of beer. The Trappist beer of the Abbey of Westvleteren has repeatedly been rated the world's best beer. The biggest brewer in the world by volume is Anheuser-Busch InBev, based in Leuven.

Sports
Sports

Since the 1970s, sports clubs are organised separately by each language community. Association football is one of the most popular sports in both parts of Belgium, together with cycling, tennis, swimming and judo. With five victories in the Tour de France and many other cycling records, Belgian Eddy Merckx is said to be one of the greatest cyclists of all time. Jean-Marie Pfaff, a former Belgian goalkeeper, is said to be one of the greatest in the history of football (soccer). Belgium and The Netherlands hosted the UEFA European Football Championship in 2000. Belgium hosted the 1972 European Football Championships.
Kim Clijsters and Justine Henin both were Player of the Year in the Women's Tennis Association. The Spa-Francorchamps motor-racing circuit hosts the Formula One World Championship Belgian Grand Prix. The Belgian driver, Jacky Ickx, won eight Grands Prix and six 24 Hours of Le Mans. Belgium also has a strong reputation in motocross. Sporting events held each year in Belgium include the Memorial Van Damme athletics competition, the Belgian Grand Prix Formula One, and a number of classic cycle races such as the Tour of Flanders and Liège–Bastogne–Liège. The 1920 Summer Olympics were held in Antwerp.

Related pages
 Belgium at the Olympics
 Belgium national football team
 List of rivers of Belgium

References

Other websites 

 Official website of Belgian monarchy
 Official website of the Belgian federal government
 Belgian Telephone directory
 Belgium Travel Guide 
 TopoMapViewer, National Geographic Institute (official map of Belgium)
European Union member states
Benelux
Current monarchies
Dutch-speaking countries
French-speaking countries
German-speaking countries
Federations
Brazil (officially called Federative Republic of Brazil; how to say: ) is a country in South America. It is the world's fifth largest country. The country has about 212 million people. The capital of Brazil is Brasília. Brazil was named after brazilwood, which is a tree that once grew very well along the Brazilian coast.

History 
The first people to come to Brazil came around 9,000 B.C. That group of indigenous people is often called the South American Indians and probably came from North America. They practiced hunting, foraging, and farming. Over thousands of years, many different indigenous people were living there.
Pedro Álvares Cabral was the first European to see Brazil. He saw it in 1500. He was from Portugal and the Portuguese kingdom claimed Brazil. Soon, Portugal colonized Brazil and created colonies all along the coastline. They began to import black slaves from Africa and force them to work. Because of the violence of the slave masters, many of these slaves would run away into the forest and create their own communities called quilombos.

In the late 1500s and early 1600s, the Dutch and the French tried to take some land in Brazil. Dutch, French, and Portuguese started moving inland further than the Treaty of Tordesillas said they could. This caused some fights with the Spaniards (people from Spain) and indigenous people in the area.
In 1822, Brazil claimed to be its own country and not a part of Portugal anymore. Soon there was civil war. Meanwhile, the quilombos survived and Brazil was bringing in more slaves than any other country in the Americas, even though many countries were beginning to legally abolish slavery. This led to an increase in slave revolts, especially in the 1860s and 1880s, which forced the government to change the system to keep the country stable. Slavery was legally abolished in 1888.

In 1889, there was a military coup, and Pedro II had to leave the country. In 1889, Brazil became a republic. The only people who could vote were people who owned land. There were some uprisings in the 1920s because some people thought the government was unfairly helping coffee growers. Brazil joined the Allies during World War II.
During the 1960s, the military leader Castelo Branco overthrew the government and created a dictatorship that was supported by the United States. It was very anti-communist and they imprisoned, tortured, or killed many people on the left. Since then, the country has become more democratic, but some people feel that there are still big problems in health, education, crime, poverty and social inequality.

In August 2016, then-president Dilma Rousseff was removed from office because of impeachment.

Languages
The official language of Brazil is Portuguese. Brazil is the only country in South America that speaks Portuguese but  people in South America speak Portuguese than Spanish because the population of Brazil is larger than the combined population of all the Spanish-speaking countries in South America.

Some people in Brazil speak German dialects. That came from German immigrants. 2% of Brazilians speak German as their first language. Yiddish is spoken by the elders of the Jewish community.
Other people in Brazil speak their ancestors' languages like Italian, Japanese, Polish, Ukrainian, French, Russian, Lithuanian, Chinese, Dutch and Korean. Spanish or "Portunhol", a mix of Portuguese and Castilian (Spanish) is spoken at some of the borders. Indigenous languages as Guarani and Aymará are the first languages of a small number of Brazilians.

Geography 
Brazil has the world's largest rainforest, the Amazon Rainforest. It makes up 40% of the country's land area. Brazil also has other types of land, including a type of savanna, called cerrado, and a dry plant region named caatinga.

The most important cities are Brasília (the capital), Belém, Belo Horizonte, Curitiba, Florianópolis, Fortaleza, Goiânia, Manaus, Porto Alegre,  Recife, Rio de Janeiro, Salvador, São Paulo (the biggest city) and Vitória.  Other cities are at List of largest cities in Brazil.
Brazil is divided into 26 states plus the Federal District in five regions (north, south, northeast, southeast and centre-west):
 North: Acre, Amazonas, Rondônia, Roraima, Pará, Amapá, Tocantins
 Northeast: Maranhão, Pernambuco, Ceará, Piauí, Rio Grande do Norte, Paraíba, Alagoas, Sergipe, Bahia
 Centre-West: Goiás, Mato Grosso, Mato Grosso do Sul, Distrito Federal/ Federal District
 Southeast: São Paulo, Rio de Janeiro, Espírito Santo, Minas Gerais
 South: Paraná, Santa Catarina and Rio Grande do Sul

The country is the fifth-largest in the world by area. It is known for its many rainforests and jungles. It is next to every country in South America except Chile and Ecuador.
The name Brazil comes from a tree named brazilwood.
Culture 
Brazil is the largest country in South America and the fifth-largest in the world. Its people are called Brazilians or Brasileiros (In Portuguese). The people include citizens of Portuguese or other European descent who mainly live in the South and Southeast, Africans, Native Americans, Arabs, Gypsies, and people of mixed ancestry. Brazil also has the largest Japanese community outside Japan. Other East Asians follow the Japanese group. The Amazon River flows through Brazil, it is the 2nd longest river in the world (after the Nile). The current President of Brazil is Jair Messias Bolsonaro. Two major sporting events were held in Brazil recently: the 2014 FIFA World Cup and the 2016 Summer Olympics in Rio de Janeiro.

Notable people 

 José Paulino Gomes, supercentenarian

Related pages 
 Civil Police (Brazil)
 Political subdivisions of Brazil
 CIA World Factbook

References

Other websites
 
 

 
Portuguese-speaking countries
1825 establishments in South America
Chemistry is a branch of science that deals with chemical elements and compounds, and how they work together and change. In other words, chemistry is the branch of science about fundamental properties of matter and chemical reactions. Chemistry is the study of the substances and their transformations (or change).

History
Before 1600, people studied substances to figure out how to do things such as turn lead into gold, but no one managed to do that. This was called alchemy. After 1600, using the scientific method alchemists became chemists. Chemists separated the air into many parts and isolated the noble gases from it. They also processed special minerals from a mine in Sweden to get rare earth metals. Radioactivity was also discovered. 118 different elements have been found. Some are very common, like oxygen. Many are very rare and expensive, like platinum. Some cannot be found on earth and can only be made in labs, like rutherfordium.
Since the 1920s, the increased understanding of physics has changed chemists' theories about chemical reactions. With smaller and faster computers, chemists have built better tools for analyzing substances. These tools have been sent to study chemicals on Mars. Police also use those tools to study evidence from crime scenes.

Types of chemistry
There are several types of chemistry. Analytical chemistry looks at which chemicals are in things. For example, looking at how much arsenic is in food. Organic chemistry looks at things that have carbon in them. For example, making acetylene. Inorganic chemistry looks at things that do not have carbon in them. One example is making an integrated circuit. Theoretical chemistry tries to explain chemical data with mathematics and computers.
A large area of chemistry is polymer chemistry. This looks at plastics. One example is making nylon. Because plastics are made of carbon, polymer chemistry is part of organic chemistry. Another area is biochemistry. This looks at the chemistry of living things. An example would be seeing how arsenic poisons people. Biochemistry is also part of organic chemistry. There are many other small branches of chemistry.

Concepts of chemistry
Basic concepts
The basic unit of an element is called an atom. An atom is the smallest building block that you can cut an element into without the element breaking down (turning into a lighter element, for example through nuclear fission or radioactive decay). A chemical compound is a substance made up of two or more elements. In a compound, two or more atoms are joined to form a molecule. The tiniest speck of dust or drop of liquid, that one can see is made up of many millions or billions of these molecules. Mixtures are substances where chemicals are mixed but not reacted. An example would be mixing sand and salt. This can be undone again to produce salt and sand separately. Chemical compounds are changed by a chemical reaction. An example would be heating sodium bicarbonate, common baking soda. It will make water, carbon dioxide, and sodium carbonate. This reaction cannot be undone.
One very important concept in chemistry is that different atoms interact with one another in very specific proportions. For example, two hydrogen atoms interacting with one oxygen atom lead to the water molecule, H2O. This relationship is known as the "Law of constant proportions" and leads to the idea of "stoichiometry", a term that refers to the ratios of different atoms in chemical compounds. For example, in water, there are always exactly 2 hydrogen atoms to 1 oxygen atom. In carbon dioxide, there are exactly 2 oxygen atoms for 1 carbon atom. These relationships are described using chemical formulas such as H2O (two hydrogen atoms and one oxygen atom) and CO2 (one carbon atom and two oxygen atoms).
Mole
Because atoms of different elements react with one another in very specific proportions but atoms of different elements have different weights, chemists often describe the number of different elements and compounds in terms of the number of "moles". A "mole" of any element contains the same number of atoms: 602,214,150,000,000,000,000,000 atoms. The atomic mass of an element can be used to see how much of the element makes a mole. For example, the atomic mass of copper is about 63.55. That means about 63.55 grams of copper metal has a mole of atoms. The atomic mass of chlorine is about 35.45. That means 35.45 grams of chlorine has a mole of atoms in it.
Moles can be used to see how many molecules are in chemical compounds, too. Copper(II) chloride is an example. CuCl2 is its chemical formula. There is one copper atom (63.55) and two chlorine atoms (35.45 · 2 = 70.90). Add all the molar masses of the elements together to get the molar mass of the chemical compound (63.55 + 70.90 = 134.45). That means in 134.45 grams of copper(II) chloride, there is one mole of copper(II) chloride molecules. This concept is used to calculate how much chemicals are needed in a chemical reaction if no reactants (chemicals that are reacted) should be left. If too much reactant is used, there will be some reactants left in the chemical reaction.
Acids and bases
Acids and bases are common chemicals. Acids release H+ ions when in water, and bases release OH− ions when in water. Acids can react with bases. The H+ ion is taken from the acid by the base. This makes water, H2O. A salt is also made when an acid and a base react together. An example would be reacting hydrochloric acid (HCl) and sodium hydroxide (NaOH). Hydrochloric acid releases H+ and Cl- ions in water. The base releases Na+ and OH- ions. The H+ and the OH- react to make water. There is a solution of sodium chloride (NaCl) left. Sodium chloride is a salt.

Usefulness
Chemistry is very useful in everyday life and makes up the foundation of many branches of science. Most objects are made by chemists (people who do chemistry). Chemists are constantly working to find new and useful substances. Chemists make new drugs and materials like paints that we use every day.

Safety
Safety

Many chemicals are harmless, but there are some chemicals that are dangerous. For example, mercury(II) chloride is very toxic. Chromates can cause cancer. Tin(II) chloride pollutes water easily. Hydrochloric acid can cause bad burns. Some chemicals like hydrogen can explode or catch fire. To stay safe, chemists experiment with chemicals in a chemical lab. They use special equipment and clothing to do reactions and keep the chemicals contained. The chemicals used in drugs and in things like bleach have been tested to make sure they are safe if used correctly.

Related pages 

 Periodic table
 List of common elements
 Laboratory techniques
 Aerosol

References
Chemical compound, a chemical combination of two or more chemical elements
 Compound word, a word made from two or more other words
Computer science deals with the theoretical foundations of computation and practical techniques for their application.
Computer science is the science of information. Computer scientists study different ways of reading, using, and encoding information.

There are many different areas within computer science. In some areas, scientists only work with ideas "on paper". In other areas they use those ideas to make things like computers and computer programs.

A person who works in computer science will often need to understand logic and mathematics.

Common tasks for a computer scientist

Asking questions 
This is so people can find new and easier ways to do things, and the way to approach problems with this information.
While computers can do some things easily (like simple math, or sorting out a list of names from A-to-Z), computers cannot answer questions when there is not enough information, or when there is no real answer. Also, computers may take too much time to finish long tasks. For example, it may take too long to find the shortest way through all of the towns in the USA - so instead a computer will try to make a close guess. A computer will answer these simpler questions much faster.

Answering the question 
Algorithms are a specific set of instructions or steps on how to complete a task. For example, a computer scientist wants to sort playing cards. There are many ways to sort them - by suits (diamonds, clubs, hearts, and spades) or by numbers (2, 3, 4, 5, 6, 7, 8, 9, 10, Jack, Queen, King, and Ace).  By deciding on a set of steps to sort the cards, the scientist has created an algorithm. The scientist then needs to test whether this algorithm works. This shows how well and how fast the algorithm sorts cards.
A simple but slow algorithm is: pick up two cards and check whether they are sorted correctly. If they are not, reverse them. Then do it again with another two, and repeat them all until they are all sorted. This is called a bubble sort. This method will work, but it will take a very long time.
 
A better algorithm is: find the first card with the smallest suit and smallest number (2 of diamonds), and place it at the start. After this, look for the second card, and so on. This algorithm is much faster, and does not need much space. This algorithm is called a "selection sort".

Ada Lovelace wrote the first computer algorithm in 1843, for a computer that was never finished. Computers began during World War II. Computer science separated from the other sciences during the 1960s and 1970s. Now, computer science has its own methods, and has its own technical terms. It is related to electrical engineering, mathematics, and language science.
Computer science looks at the theoretical parts of computers. Computer engineering looks at the physical parts of computers (hardware). Software engineering looks at the use of computer programs and how to make them.

Parts of computer science

Central math 
 Boolean algebra (when something can only be true or false)
 Computer numbering formats (how computers count)
 Discrete mathematics (math with numbers a person can count)
 Symbolic logic (clear ways of talking about math)
Order of operations (which math operations are performed first)
How an ideal computer works 
 Algorithmic information theory (how easily can a computer answer a question?)
 Complexity theory (how much time and memory does a computer need to answer a question?)
 Computability theory (can a computer do something?)
 Information theory (math that looks at data and how to process data)
 Theory of computation (how to answer questions on a computer using algorithms)
 Graph theory (math that looks for directions from one point to another)
 Type theory (what kinds of data should computers work with?)
 Denotational semantics (math for computer languages)
 Algorithms (looks at how to answer a question)
 Compilers (turning words into computer programs)
 Lexical analysis (how to turn words into data)
 Microprogramming (how to control the most important part of a computer)
 Operating systems (big computer programs, e.g. Linux, Microsoft Windows, Mac OS)  to control the computer hardware and software.
 Cryptography (hiding data)
Parallel computing (many instructions are carried out simultaneously)
 Theoretical computer science (how information can be processed)
Computer science at work 
 Artificial intelligence (making computers learn and talk, similar to people)
 Computer architecture (building a computer)
 Computer graphics (making pictures with computers)
 Computer networks (joining computers to other computers)
 Computer program (how to tell a computer to do something)
 Computer programming (writing, or making, computer programs)
 Computer security (making computers and their data safe)
 Databases (a way to sort and keep data)
 Data structure (how to build or group data)
 Distributed computing (using more than one computer to solve a difficult problem)
 Information retrieval (getting data back from a computer)
 Programming languages (languages that a programmer uses to make computer programs)
 Program specification (what a program is supposed to do)
 Program verification (making sure a computer program does what it should do, see debugging)
 Robots (using computers to control machines)
 Software engineering (how programmers write programs)
Blockchain (use blockchain technology for security, and privacy)
What computer science does 
 Benchmark (testing a computer's power or speed)
 Computer vision (how computers can see and understand images)
 Collision detection (how computers help robots move without hitting something)
 Data compression (making data smaller)
 Data structures (how computers group and sort data)
 Data acquisition (putting data into computers)
 Design patterns (answers to common software engineering problems)
 Digital signal processing (cleaning and "looking" at data)
 File formats (how a file is arranged)
 Human-computer interaction (how humans use computers)
 Information security (keeping data safe from other people)
 Internet (a large network that joins almost all computers)
 Web applications (computer programs on the Internet)
 Optimization (making computer programs work better)
 Software metrics (ways to measure computer programs, such as counting lines of code or number of operations)
 VLSI design (the making of a very large and complex computer system)
Related pages
 Computing
 Formal language
 Turing Award
 Computer jargon
 Encyclopedia of Computer Terms

References
The processor of a computer is made from integrated circuits (chips) that contains many transistors. Most computers are digital, which means that they represent information using binary digits, or bits. Computers come in different shapes and sizes, depending on the brand, model, and purpose. They range from small computers, such as smartphones and laptops, to large computers, such as supercomputers.

Characteristics 
The two things make it a computer are that it responds to a specific instruction set in a well-defined manner, and that it can execute a stored list of instructions called a program. There are four main actions in a computer: inputting, storing, outputting and processing.
Modern computers can do billions of calculations in a second. Being able to calculate many times per second allows modern computers to multi-task, which means they can do many different tasks at the same time. Computers do many different jobs where automation is useful. Some examples are controlling traffic lights, vehicles, security systems, washing machines and digital televisions.

Computers can be designed to do almost anything with information. Computers are used to control large and small machines that, in the past, were controlled by humans. Most people have a personal computer at home or at work. They are used for things such as calculation, listening to music, reading an article, writing, or playing games.
Hardware 
Modern computers are electronic computer hardware. They do mathematical arithmetic very quickly, but computers do not really "think." They only follow the instructions in their software programs. The software uses the hardware when the user gives it instructions and produces useful outputs.

Controls 
Computers are controlled with user interfaces. Input devices which include keyboards, computer mice, buttons, and touch screens, etc.

Programs 
Computer programs are designed or written by computer programmers. A few programmers write programs in the computer's own language, called machine code. Most programs are written using a programming language like C, C++, JavaScript. These programming languages are more like the language with which one talks and writes every day. The compiler converts the user's instructions into binary code (machine code) that the computer will understand and do what is needed.

History of computers
First computer 
In 1837, Charles Babbage proposed the first general mechanical computer, the Analytical Engine. The Analytical Engine contained an Arithmetic Logic Unit, basic flow control, punched cards, and integrated memory. It is the first general-purpose computer concept that could be used for many things and not only one particular computation. However, this computer was never built while Charles Babbage was alive, because he didn't have enough money. In 1910, Henry Babbage, Charles Babbage's youngest son, was able to complete a portion of this machine and perform basic calculations.
One of the first examples of this was built by Hero of Alexandria (c. 10–70 AD). He built a mechanical theater which performed a play lasting 10 minutes and was operated by a complex system of ropes and drums. These ropes and drums were the language of the machine- they told what the machine did and when. Some people argue that this is the first programmable machine.

Some people disagree on which early computer is programmable. Many say the "castle clock", an astronomical clock invented by Al-Jazari in 1206, is the first known programmable analog computer. The length of day and night could be adjusted every day in order to account for the changing lengths of day and night throughout the year. Some count this daily adjustment as computer programming.

Others say the first computer was made by Charles Babbage. Ada Lovelace is considered to be the first programmer.
The computing era 
At the end of the Middle Ages, people started thinking math and engineering were more important. In 1623, Wilhelm Schickard made a mechanical calculator. Other Europeans made more calculators after him. They were not modern computers because they could only add, subtract, and multiply- you could not change what they did to make them do something like play Tetris. Because of this, we say they were not programmable. Now engineers use computers to design and plan.
In 1801, Joseph Marie Jacquard used punched paper cards to tell his textile loom what kind of pattern to weave. He could use punch cards to tell the loom what to do, and he could change the punch cards, which means he could program the loom to weave the pattern he wanted. This means the loom was programmable. At the end of the 1800s Herman Hollerith invented the recording of data on a medium that could then be read by a machine, developing punched card data processing technology for the 1890 U.S. census. His tabulating machines read and summarized data stored on punched cards and they began use for government and commercial data processing.

Charles Babbage wanted to make a similar machine that could calculate. He called it "The Analytical Engine". Because Babbage did not have enough money and always changed his design when he had a better idea, he never built his Analytical Engine.
As time went on, computers were used more. People get bored easily doing the same thing over and over. Imagine spending your life writing things down on index cards, storing them, and then having to go find them again. The U.S. Census Bureau in 1890 had hundreds of people doing just that. It was expensive, and reports took a long time. Then an engineer worked out how to make machines do a lot of the work. Herman Hollerith invented a tabulating machine that would automatically add up information that the Census bureau collected. The Computing Tabulating Recording Corporation (which later became IBM) made his machines. They leased the machines instead of selling them. Makers of machines had long helped their users understand and repair them, and CTR's tech support was especially good.

Because of machines like this, new ways of talking to these machines were invented, and new types of machines were invented, and eventually the computer as we know it was born.
Analog and digital computers 
In the first half of the 20th century, scientists started using computers, mostly because scientists had a lot of math to figure out and wanted to spend more of their time thinking about science questions instead of spending hours adding numbers together. For example, if they had to launch a rocket ship, they needed to do a lot of math to make sure the rocket worked right. So they put together computers. These analog computers used analog circuits, which made them very hard to program. In the 1930s, they invented digital computers, and soon made them easier to program. However this is not the case as many consecutive attempts have been made to bring arithmetic logic to l3.Analog computers are mechanical or electronic devices which solve problems.Some are used to control machines as well.
High-scale computers 
Scientists figured out how to make and use digital computers in the 1930s to 1940s. Scientists made a lot of digital computers, and as they did, they figured out how to ask them the right sorts of questions to get the most out of them. Here are a few of the computers they built:
Konrad Zuse's electromechanical "Z machines". The Z3 (1941) was the first working machine that used binary arithmetic. Binary arithmetic means using "Yes" and "No." to add numbers together. You could also program it. In 1998 the Z3 was proved to be Turing complete. Turing complete means that it is possible to tell this particular computer anything that it is mathematically possible to tell a computer. It is the world's first modern computer.
 The non-programmable Atanasoff–Berry Computer (1941) which used vacuum tubes to store "yes" and "no" answers, and regenerative capacitor memory.
 The Harvard Mark I (1944), A big computer that you could kind of program.
 The U.S. Army's Ballistics Research Laboratory ENIAC (1946), which could add numbers the way people do (using the numbers 0 through 9) and is sometimes called the first general purpose electronic computer (since Konrad Zuse's Z3 of 1941 used electromagnets instead of electronics). At first, however, the only way to reprogram ENIAC was by rewiring it.
Several developers of ENIAC saw its problems. They invented a way to for a computer to remember what they had told it, and a way to change what it remembered. This is known as "stored program architecture" or von Neumann architecture. John von Neumann talked about this design in the paper First Draft of a Report on the EDVAC, distributed in 1945. A number of projects to develop computers based on the stored-program architecture started around this time. The first of these was completed in Great Britain. The first to be demonstrated working was the Manchester Small-Scale Experimental Machine (SSEM or "Baby"), while the EDSAC, completed a year after SSEM, was the first really useful computer that used the stored program design. Shortly afterwards, the machine originally described by von Neumann's paper—EDVAC—was completed but was not ready for two years.