Britannica Student Encyclopedia - 2010

The circulatory system of humans consists

of two parts: the cardiovascular

system and the lymphatic system. The

main fluid in humans and most other

animals is blood. It is transported

through the cardiovascular system. This

system consists of the heart and a network

of blood vessels. The fluid that

helps fight infections is called lymph. It

is carried in the lymphatic system.

#More to explore

Cardiovascular System • Lymphatic

System

Circus

A circus is a form of entertainment that

features many different spectacular acts.

These acts usually include skilled and

daring performers, highly trained animals,

and funny clowns.

Circus acts often perform in a circle, or

ring, with the audience on all sides. Big

Circus clowns need to have

many kinds of performing skills.

BRITANNICA STUDENT ENCYCLOPEDIA Circus 119

circuses may have three rings with different

acts inside each one. At one time,

circuses put up a tent, known as the big

top, to enclose the rings. Many circuses

now use indoor arenas.

Circus Acts

Most circuses have many animal acts.

Trick riders perform acrobatics on horseback

or ride two horses at once.

Elephants rise up on their hind legs or

stand on their head. Other wild animal

acts include dancing bears and tigers

that jump through fiery hoops.

Human performers also amaze the audience.

Some people walk a tightrope,

swing from a hanging bar called a trapeze,

or get shot out of a cannon.

Clowns make the audience laugh with

dancing, juggling, and comedy. They

paint their faces white and wear goofy

costumes.

The ringmaster—a dashing figure in

high boots and a top hat—announces

acts and sets the pace. A brass band adds

to the excitement.

Circus History

In ancient Rome the circus was an arena

for races and fights. A performer named

Philip Astley created the modern circus

in England in 1768. He built a performance

ring where he did tricks on

horseback for paying customers. He

soon added clowns, acrobats, and other

acts. As he toured, he spread the circus

idea throughout Europe.

Circuses also spread to the United

States. Circus performers and animals

often traveled from town to town in

wagons or trains. They paraded through

a town’s streets before the first show

there. In the 1880s two U.S. circus owners,

P.T. Barnum and James A. Bailey,

combined their shows to create a huge

circus. They called it “The Greatest

Show on Earth.” The Ringling brothers

bought that circus in the early 1900s.

They joined it with their own circus to

form the Ringling Bros. and Barnum &

Bailey Circus. The main tent could seat

10,000 people.

Many circuses closed in the mid-1900s.

After 1956, the Ringling Bros. and Barnum

& Bailey Circus stopped using

tents and moved indoors. Nevertheless,

families today can still enjoy that circus

and others. One of the biggest modern

circus events is the circus festival of

Monte-Carlo, in Monaco. Another

Circus

parades, featuring

brightly

painted and

decorated

wagons, once

marched

through towns

to show off the

animals and

performers.

Trapeze artists were popular circus performers

during the 1800s.

120 Circus BRITANNICA STUDENT ENCYCLOPEDIA

popular modern circus is the Cirque du

Soleil of Montreal, Canada, which uses

no animal acts.

#More to explore

Theater

Citizenship

Citizenship is everything that has to do

with being a citizen, or full member, of a

country. Citizens have rights that are

given by the country’s government. For

example, citizens have the right to be

protected by a country’s laws. In return,

citizens have duties that they owe to the

country. One of the most important

duties is being loyal to the country.

Citizenship is different than nationality.

A person’s nationality tells which country

that person (called a national) is

from. But nationals from a certain country

are not always citizens of that country.

They may have gained citizenship in

another country. Or they may have lost

their citizenship. People who live in a

country but are not citizens or nationals

of that country are called aliens.

Becoming a Citizen

Every country has its own rules about

who is a citizen and how to become one.

Many countries have set up four basic

ways to become a citizen. First, anyone

who is born in the country is a citizen of

that country. Second, anyone whose

mother or father is a citizen of the country

is also a citizen. Third, anyone who

is married to a citizen becomes a citizen.

Fourth, a person who goes through a

process called naturalization becomes a

citizen.

Naturalization is a way for people who

are born in one country to become citizens

of another country. Laws on naturalization

are different from country to

country. Usually, aliens who want to be

naturalized must have lived in the new

country for several years. They usually

must speak the country’s language. They

may have to pass a test about the laws

and history of the country. They often

must take an oath, or swear to be loyal

to the country. However, not every

country allows aliens to become naturalized

citizens.

Rights and Responsibilities

Citizens have certain rights. Some countries

give their citizens more or different

rights than other countries. Citizens

usually have the right to vote. They usually

have the right to be elected to government

jobs as well. Other rights of

citizens may include the right to follow

any religion and the right to speak freely.

Citizens also have duties, or responsibilities.

Voting is a responsibility as well as a

right. Citizens must vote to make sure

People from more than 40 countries are

made U.S. citizens during a ceremony on

Ellis Island, near New York City.

The idea of

citizenship first

arose in

ancient

Greece. A

citizen in a

Greek citystate

was able

to vote. He

also had to

pay taxes and

serve in the

military.

BRITANNICA STUDENT ENCYCLOPEDIA Citizenship 121

that their government works for the

good of its citizens. Citizens also may

have the duty to serve on a jury during a

trial in court. Some countries make serving

in the military a duty of all citizens.

Aliens may have some of the same rights

as citizens. But they usually cannot vote

or serve in the government. Aliens also

have some of the same responsibilities as

citizens. They must obey the country’s

laws. They often must pay taxes as well.

Losing Citizenship

People cannot lose their citizenship

except in very special cases. A government

may take away the citizenship of

someone who becomes a naturalized

citizen of another country. A government

also may take away the citizenship

of people who show allegiance, or loyalty,

to another country. Examples of

this include voting in a foreign election

and serving in a foreign military. Trying

to overthrow the government by force is

a serious crime that can result in loss of

citizenship. Naturalized citizens who

commit serious crimes may lose their

citizenship as well.

People who have lost their citizenship

can end up as citizens of no country.

These people are called stateless persons.

#More to explore

Civil Rights • Country • Government

• Voting

Citrus Fruit

Oranges, grapefruit, lemons, limes,

shaddocks, and citrons are all types of

citrus fruit. Citrus fruits have a juicy

pulp inside a leathery skin. They grow

on trees, bushes, or shrubs. Citrus plants

belong to the rue family of flowering

plants. This family also includes the tiny

orange fruits called kumquats.

Where Citrus Fruits Grow

Citrus fruits grow in warm regions in

many parts of the world. They grew first

in southern China and other parts of

Asia. Arab traders brought citrus fruits

to the Middle East, Africa, and Europe.

European explorers brought citrus fruits

to the Americas by the 1500s.

Farmers often grow citrus trees in areas

called groves. Citrus plants may also

grow in the wild or in people’s gardens.

Physical Features

Citrus fruits have leathery peels, or

rinds. Inside the rind, the flesh, or pulp,

is divided into eight or more sections.

Each section contains many tiny, juicy

Citrus fruits include oranges, grapefruit,

lemons, and limes. They are healthy

because they contain a lot of vitamin C.

122 Citrus Fruit BRITANNICA STUDENT ENCYCLOPEDIA

pouches and seeds. However, farmers

have learned how to grow seedless varieties

of many types of citrus fruit.

Oranges and grapefruit are round.

Oranges are usually orange in color.

Grapefruit are yellow and often larger

than oranges. Orange trees and grapefruit

trees often reach 20 feet (6 meters)

in height. Both types of tree have white

flowers and shiny, green leaves.

Lemons and limes are more oval in

shape. They often have a bump on one

end. Lemons are yellow and larger than

limes, which are green. Lemon trees and

lime trees are generally smaller than

orange or grapefruit trees. Lemon trees

have purple and white flowers and reddish

or green leaves. Lime trees have

white flowers and pale green leaves.

Shaddocks are also called pummelos.

They are big, yellow fruits with a round

or pearlike shape. Their pulp is pale or

red. Shaddock trees grow to a height of

20 to 43 feet (6 to 13 meters). They

have shiny, green leaves and large, white

flowers.

Citrons look like large lemons. They

have whitish pulp. The rind has a thin

outside layer and a thick inside layer.

Citron trees grow to about to about 11.5

feet (3.5 meters) tall. They have pale

green leaves and purple or white flowers.

Uses

Citrus fruits are a healthy food because

they are rich in vitamin C. Many people

eat citrus fruits raw or squeeze them to

make juice. People also use citrus fruits

to flavor drinks and cooked dishes. In

addition, citrus fruits may be canned or

made into jam.

Citrus rinds provide oil that may be

used as a flavoring or in making perfume

and medicines. Rinds may also be

cooked with sugar to make candy.

#More to explore

Fruit • Grapefruit • Lemon • Lime

• Orange

City

A city is a place where many people live

closely together. City life has many benefits.

Cities bring together a great variety

of people from different backgrounds.

They offer more jobs, more schools, and

more kinds of activities than smaller

towns and villages. But cities also can be

dangerous and polluted.

About half the world’s people live in

cities. Tokyo, Japan, has more people

than any other metropolitan area. (A

city’s metropolitan area includes the city

itself and other places close by.) New

York City is the largest city in the

United States.

City Features

A city’s central business district, or

downtown, usually has its tallest office

buildings and biggest stores. The downtown

area is often the oldest part of the

city. A city usually has one or more areas

of factories and warehouses (storage

buildings) outside of downtown. Most

of the city’s homes lie still farther from

downtown.

More than

100 million

tons of citrus

fruits are produced

every

year. Oranges

make up more

than half of

the total.

BRITANNICA STUDENT ENCYCLOPEDIA City 123

Cities usually have a variety of places for

entertainment and relaxation. These

include museums, concert halls, theaters,

parks, and sports arenas.

Cities commonly have a public

transportation system to help people get

around without cars. Public

transportation includes buses, trains,

and subways. Subways are trains that

run underground.

Built-up areas called suburbs lie outside

the boundaries of most cities. Suburbs

tend to have more houses and apartments

than businesses. Many people live

in the suburbs and commute, or travel,

to their jobs in the city.

City Government

Like countries and states, cities have a

government. A city government usually

includes a group of elected lawmakers

called the city council. Most cities also

elect a leader called a mayor. In other

cities the city council names a leader

called a city manager.

City governments provide many services.

These include police protection,

firefighting, hospitals, and schools.

Tokyo and its surrounding areas have more people than any other city in the world.

Suburbs usually have more

houses than businesses. People

who live in the suburbs often

work in a nearby city.

124 City BRITANNICA STUDENT ENCYCLOPEDIA

Many cities also support museums and

libraries.

City Problems

Cities attract people looking for work,

education, and other ways to improve

their lives. But city life can also be hard.

Not everyone shares equally in the benefits

of the city. Some people live in rundown,

overcrowded housing. Others

have no homes at all. They sometimes

live on city streets. Crowded living conditions

in cities also lead to crime, traffic,

and pollution.

History

About 5,500 years ago people in Mesopotamia

(now Iraq) started the first cities.

Rome (now in Italy) may have been

the largest ancient city. Between

250,000 and 1.6 million people lived

there.

Some cities in ancient times and in the

Middle Ages (AD 500–1500) were independent

of any country. They were

called city-states. City-states ruled themselves

and the surrounding area. Athens

and Sparta were major city-states of

ancient Greece. From the 1000s to the

1400s Florence, Venice, and other citystates

were important in what is now

Italy. After the Middle Ages these cities

lost their independence. Today almost

all cities belong to a particular country.

The Industrial Revolution, which

started in the late 1700s, contributed to

the growth of cities. New machines

invented during this period made manufacturing

an important business. Many

people from the countryside moved into

cities. They looked for work in newly

built factories.

In the late 1800s architects invented

new building methods that changed the

way cities looked. Tall buildings called

skyscrapers appeared in many cities.

During the 1900s cities continued to

change. They grew rapidly in

population. They also spread outward.

Many people moved to the suburbs.

Some highly populated areas became

known as megalopolises. Megalopolises

often include several cities and many

suburbs.

#More to explore

Architecture • City-State • Government

• Industrial Revolution • Pollution

• Skyscraper • Transportation

Ruins of an ancient city called Harappa

stand in present-day Pakistan. Harappa

was one city of the Indus Valley civilization,

which lasted from about 2500 BC to about

1700 BC.

BRITANNICA STUDENT ENCYCLOPEDIA City 125

City-State

Almost every modern city is part of a

country. In ancient times and in the

Middle Ages, however, there were cities

that were independent. They are known

as city-states. Each city-state governed

only itself and the surrounding countryside.

City-states date back to the earliest years

ofWestern civilization. Between 5000

BC and 2500 BC about a dozen citystates

arose in Mesopotamia (modernday

Iraq). After 2300 BC, however, these

city-states lost their independence and

were forced to become part of the Akkadian

Empire.

City-states developed again in ancient

Greece, where mountains separated

communities from each other. The

Greek city-states tried many kinds of

government. Athens is considered to be

the birthplace of democracy. Sparta was

a military stronghold ruled by kings.

Without lasting alliances, however, the

Greek city-states were too weak to resist

invaders. The Macedonians and later the

Romans conquered Greece, and most

city-states fell into ruin. Athens survives

today as a modern city.

City-states emerged again in Europe

during the Middle Ages. Venice, Florence,

Genoa, Amalfi, and other citystates

dominated the culture of what is

now Italy from the 1000s to the 1400s.

City-states also developed in what are

now northern Germany and Belgium.

They prospered from trade until they

lost their independence to larger kingdoms.

One modern country that is considered

a city-state is Singapore, which broke off

from Malaysia in 1965. Its unique

geography—a large island containing

one major city—allowed it to develop as

a self-governing city-state.

#More to explore

City • Greece, Ancient • Mesopotamia

• Singapore

Civilization

A civilization is a large group of people

who share certain advanced ways of living

and working. Civilizations came

about as humans started living in cities.

City people developed advanced forms

of culture and government. Eventually,

Venice and Genoa, now both in

Italy, were important city-states

during the Middle Ages. Sailors

used charts called portolans to

find these cities and others on

the Mediterranean Sea.

126 City-State BRITANNICA STUDENT ENCYCLOPEDIA

this advanced lifestyle spread to people

in large regions around cities.

How Civilizations Developed

The first civilizations developed in

regions where farmers grew enough food

to feed themselves and others. The

people who did not farm began to live

in larger villages, which grew into cities.

These people practiced arts and crafts

that they could trade for food. They

developed writing systems to keep track

of trade. They started transportation

networks to carry goods between farm

and city. City people also created governments

and laws. They developed

advanced religious practices as well.

Early Civilizations

The earliest civilizations developed in

river valleys because the land there was

good for farming. The world’s first civilization

formed in Mesopotamia. This

land was between the Tigris and Euphrates

rivers in what is now Iraq. People

first started settling there in about 4500

BC. The world’s second civilization

developed along the Nile River in about

2925 BC. It is now known as ancient

Egypt.

By about 2500 BC another ancient civilization

had formed in the valley of the

Indus River. This was located around

what is now the border between India

and Pakistan. Ancient Chinese civilization

developed by about the 1700s BC

around the Huang He, or Yellow River.

Later Civilizations

Since these beginnings many great civilizations

have risen and fallen. The

ancient Greeks and Romans built civilizations

in Europe. The Maya, Aztec, and

Inca formed civilizations in the Americas.

African peoples developed civilizations

centered around such cities as

Aksum and Great Zimbabwe. Arabs

created an Islamic civilization in the

Middle East and North Africa.

Today most people in the world belong

to a civilization. European and American

civilization is often calledWestern

civilization. African, Asian (or Eastern),

and other civilizations are sometimes

known as non-Western civilizations.

#More to explore

City • Culture • Egypt, Ancient

• Government • Indus Valley

Civilization • Mesopotamia

The word

civilization

comes from

the Latin word

civis, which

means “city

dweller.” Latin

was the language

of

ancient Rome.

A carving shows Hammurabi

(left), a king of Babylon. Babylon

was a part of the ancient civilization

that developed in Mesopotamia,

in what is now Iraq.

BRITANNICA STUDENT ENCYCLOPEDIA Civilization 127

Civil Rights

All people have certain rights. These are

often divided into human rights and

civil rights. Human rights include the

right to live as a free person, the right to

have shelter and food, and the right not

to be mistreated. These rights belong to

all humans just because they are human.

Civil rights are rights that are granted to

citizens by a government. For example,

governments may decide who can vote,

who can buy property, or who can be

educated.

The Development of Civil

Rights

The idea that governments should give

people certain rights is a modern one.

Before the 1700s groups of people sometimes

fought for better treatment from a

king or a ruler. In these cases, however,

they wanted rights only for their own

group. For instance, the Magna Carta

was a document that granted rights to

noblemen in England. The king signed

it in 1215. But most people still had no

way to complain if the king mistreated

them.

In the 1700s some people began to talk

about the idea that all people had certain

rights. They thought that it was

wrong for kings to ignore these rights.

This idea led some people to fight two

major revolutions against their kings—

the American Revolution and the

French Revolution. Afterward, the

Americans and the French set up new

forms of government run by the people.

These governments granted certain civil

rights to the people. In the United

States, the Bill of Rights of the U.S.

Constitution listed many of these rights.

France used a similar list, the Declaration

of the Rights of Man and of the

Citizen, as a part of its first constitution.

The Fight for Equal Rights

However, even these new governments

did not give equal rights to all citizens.

Women did not have the right to vote in

the United States until the 1920s.

French women could not vote until

1945. African Americans were enslaved

in parts of the United States until the

mid-1860s. Even after they gained freedom,

the government did not always

protect their rights. They fought to gain

the same civil rights as whites for many

years. The civil rights movement that

began in the 1950s was a part of this

struggle. Today people in some countries

are still fighting to gain the same civil

rights that other citizens have.

#More to explore

Bill of Rights • Civil Rights Movement

• Human Rights • Magna Carta

A man votes in South Africa. Voting

became a civil right for both black and

white South Africans in the 1990s.

128 Civil Rights BRITANNICA STUDENT ENCYCLOPEDIA

Civil Rights

Movement

The rights of a country’s citizens are

called civil rights. Many African Americans

were denied full civil rights for

about 100 years after the end of slavery.

The struggle for those rights, especially

in the 1950s and 1960s, is known as the

civil rights movement.

Before the CivilWar most blacks in the

United States were slaves, who had no

civil rights. After the war ended in 1865,

blacks made some progress. Between

1865 and 1870 the 13th, 14th, and

15th amendments to the U.S. Constitution

ended slavery and gave citizenship

and voting rights to former slaves.

These rights were often ignored, however,

especially in the South. To keep

poor African Americans from voting,

some states made people pay a tax or

pass a difficult test before they could

vote. Violent groups such as the Ku

Klux Klan tried to scare blacks away

from the polls. Southern governments

passed laws to keep African Americans

separate, or segregated, from whites. In

many places, for example, black children

were not allowed to attend the same

schools as white children.

Some African Americans resisted this

unfair treatment all along. But not until

the 20th century did blacks organize

themselves into a movement. The most

important leader in the early years of the

civil rights movement was W.E.B. Du

Bois. In 1909 he and others formed the

National Association for the Advancement

of Colored People (NAACP). The

NAACP used the courts to fight for civil

rights for blacks.

Events of the 1950s

The civil rights movement won its first

major victory in 1954, in the court case

of Brown vs. Board of Education of

Topeka, Kansas. NAACP lawyers led by

Thurgood Marshall argued the case

before the U.S. Supreme Court. The

Court ruled that separate schools for

whites and blacks were unequal and

therefore violated the Constitution.

On December 1, 1955, in Montgomery,

Alabama, a black woman named Rosa

Parks was arrested for refusing to give up

her seat on a bus to a white person.

Blacks protested her arrest by boycotting

(refusing to use) the bus system. Late in

1956 the Supreme Court ruled that seg-

W.E.B. Du Bois (center row, second from

right) and other early leaders of the civil

rights movement are pictured in 1905.

The U.S.

Supreme

Court ruled

that racial segregation

was

legal in 1896.

The Court

reversed this

decision in

1954.

BRITANNICA STUDENT ENCYCLOPEDIA Civil Rights Movement 129

regation on public transportation was

unconstitutional. One of the leaders of

the boycott was a young minister named

Martin Luther King, Jr. In the late

1950s King organized the Southern

Christian Leadership Conference, a

group dedicated to peaceful civil rights

activities.

Many white people resisted change,

especially in the South. In 1957 whites

rioted at a high school in Little Rock,

Arkansas, when the first black students

enrolled there. U.S. President Dwight

D. Eisenhower sent soldiers to restore

order.

Events of the 1960s

In 1960 the civil rights movement began

using a form of protest called the sit-in.

Protesters sat down in a place where they

knew they would not be served, such as

a segregated lunch counter, and refused

to leave. Though the protesters were

often harassed or arrested, they

remained peaceful, which created sympathy

for their cause. A group called the

Student Nonviolent Coordinating Committee

organized many sit-ins.

In 1961 a group called the Congress of

Racial Equality began sponsoring Freedom

Rides through the South. African

Americans and whites traveled together

to make sure buses and stations were

integrated. Some Freedom Riders were

beaten or arrested. In Alabama a bus was

bombed.

In August 1963 about 250,000 people

gathered in Washington, D.C., to urge

Congress to pass a civil rights law. The

people sang “We Shall Overcome,” and

King delivered a powerful speech

known for the phrase “I Have a

Dream.” The event was called the

March on Washington.

The civil rights movement won major

victories with the passage of new laws in

1964 and 1965. The Civil Rights Act of

1964 was the most extensive civil rights

law in U.S. history. It outlawed discrimi-

In 1958 a group of African American children

take part in a protest against a restaurant

in Oklahoma. The restaurant had

refused to serve African Americans.

Crowds of people protested for civil rights

at the March on Washington in 1963.

130 Civil Rights Movement BRITANNICA STUDENT ENCYCLOPEDIA

nation in public places, in hiring, and in

government programs. It also ended

registration requirements and other

obstacles to voting. The Voting Rights

Act of 1965 ended other voting restrictions

and led to a great increase in the

number of black voters.

Beyond the Civil Rights

Movement

Some African Americans were not

satisfied with the progress made by the

civil rights movement. Frustration led

to rioting in several cities between 1965

and 1967. Some blacks formed groups

that were willing to use violence to win

racial justice. Malcolm X was an early

leader of this “black power” movement.

In 1968 King was assassinated in

Memphis, Tennessee. His murder ended

the civil rights movement as a unified

effort.

In the years that followed, however,

many civil rights leaders continued to

work for racial equality by running for

political office. The number of black

public officials grew dramatically. Black

leaders sought to help African Americans

by supporting affirmative-action

programs. These programs tried to make

up for past wrongs by assuring economic

and educational opportunities for

blacks, women, and other groups.

#More to explore

African Americans • Du Bois,W.E.B.

• King, Martin Luther, Jr. • Marshall,

Thurgood • National Association for the

Advancement of Colored People

• Slavery

CivilWar,

American

#see American Civil War.

CivilWar,

Spanish

#see Spanish Civil War.

Clam

#see Bivalve.

Classical Music

The term classical music has several

meanings. Many countries call their own

traditional or ancient music classical

music. However, inWestern parts of the

world people use the term classical

music to refer to art music.

Art music, or classical music, is different

from popular and folk music. Classical

music is more complex. It is usually

written down in a form that classical

musicians can read off the page. Classical

musicians do not frequently improvise.

To improvise means to make up

music while playing it.

Instruments and Forms

People called composers write classical

music. They write classical music for

different types of instruments. The

music may require stringed instruments,

wind instruments, keyboard instru-

Much of the

classical music

that is performed

today

was written

hundreds of

years ago.

BRITANNICA STUDENT ENCYCLOPEDIA Classical Music 131

ments, or percussion instruments, or a

combination of any of these.

Composers usually decide how many

instruments should play a musical work.

A musical work may be written for only

one instrument, a few instruments, or a

large group of instruments. An orchestra

is a large group of instruments.

History

Classical music developed in Europe

over hundreds of years. Much of the

earliest classical music was used in religious

ceremonies. Later, nonreligious

music became more popular. Musicians

often performed classical music to entertain

audiences in royal courts.

Classical musical grew and changed rapidly

from the late 1500s to the mid-

1700s. The modern orchestra was

formed during this time. Also, musicians

created new types of classical music,

such as opera. One of the greatest composers

of this time was Johann Sebastian

Bach.

Music experts call the time from about

1750 to 1820 the classical age. In this

period, musicians developed a number

of musical forms. One of them was the

symphony, a long musical composition

for an orchestra. Another was the string

quartet, a musical composition for two

violins, a viola, and a cello. Some important

composers from the classical age are

Wolfgang Amadeus Mozart and Ludwig

van Beethoven.

Beethoven’s music influenced many

classical composers of the 1800s. Much

classical music during this time was dramatic

and emotional. Some of the most

famous composers from this period are

Peter Tchaikovsky and Johannes

Brahms.

The 1900s were a time of great experimentation

in classical music. Composers

used new forms and even new instruments.

For example, electronic instruments

opened up new ways of

expression for composers and musicians.

Claude Debussy, Igor Stravinsky, and

John Cage were important composers of

the 1900s.

#More to explore

Bach, Johann Sebastian • Beethoven,

Ludwig van • Folk Music • Mozart,

Wolfgang Amadeus • Music • Opera

• Orchestra • Popular Music

Claw

#see Nail and Claw.

Clay

Clay is a natural material made up of

tiny particles of rock. When clay is

mixed with enough water, it feels like

soft, gluey mud. Unlike plain mud,

however, clay holds its shape. Clay can

be pinched, rolled, cut, or built up in

layers to form shapes of all kinds.

Wet clay makes a very useful building

material because it hardens as it dries.

Clay baked, or fired, in an oven becomes

especially hard and may last a very long

time. Archaeologists have found pots

The ancient

Greeks

selected and

arranged the

tones, or

sounds, on

which Western

classical music

is based.

132 Claw BRITANNICA STUDENT ENCYCLOPEDIA

and bowls made of clay that are thousands

of years old.

Like many other minerals, clay is mined,

or dug up, from the ground. Before clay

can be used, it must be cleaned. Cleaning

removes small pieces of rock and

other debris, or unneeded materials.

Sometimes workers add sand to the clay

to make it stronger.

People use different types of clay to

make many things, including dishes,

flowerpots, tiles, sewer pipes, sinks, toilets,

and bricks. Kaolin, or china clay, is

the most valuable type of clay. It is

important in the manufacture of fine

china and porcelain. It is also used to

make rubber, paint, and paper. A very

fine coating of kaolin gives certain

papers a smooth surface. Kaolin is usually

white in color. Other types of clay

may be tan, brown, red, or gray.

Craftspeople who make things from clay

sometimes use a pottery wheel to shape

the clay. A pottery wheel is a round, flat

surface that rotates, or spins. Clay placed

on a pottery wheel can be shaped into

such objects as vases, jars, and pots.

#More to explore

Brick and Tile • Pottery

Cleary, Beverly

Beverly Cleary is a popular author of

lively, funny children’s books. Her stories

are often based on her own adventures

as a child in Portland, Oregon.

Early Life

Beverly Bunn was born in McMinnville,

Oregon, on April 12, 1916. She moved

to Portland with her family when she

was 6. Beverly struggled with reading as

a child. But with the help of her mother,

she learned to read at the age of 8. She

developed a great love for reading and

often visited the local library.

Career

In 1940 Beverly married Clarence

Cleary. She decided to become a fulltime

author after working as a librarian

in the 1940s. Her books are about kids

A worker makes pipes from clay in China.

Beverly Cleary

BRITANNICA STUDENT ENCYCLOPEDIA Cleary, Beverly 133

and their adventures—subjects that she

would have liked to read about as a

child.

Cleary published her first book, Henry

Huggins, in 1950. Since then she has

published more than 35 books. Her

best-known books include The Mouse

and the Motorcycle (1965), Ramona and

Her Father (1977), Ramona Quimby, Age

8 (1981), Dear Mr. Henshaw (1983),

Beezus and Ramona (1987), and Muggie

Maggie (1990).

Cleary’s books have been published in

many different languages. Cleary has

won the Newbery Medal three times.

The Newbery is a yearly prize awarded

to outstanding books for children.

Clemens, Samuel

Langhorne

#see Twain, Mark."

Cleopatra

Cleopatra was a queen of ancient

Egypt. She wanted to make her country

more powerful. To do so, she got the

help of two leaders of ancient Rome:

Julius Caesar and Mark Antony.

However, a third Roman leader,

Augustus, defeated her.

Early Years

Cleopatra was born in 69 BC in the city

of Alexandria in Egypt. Her family originally

came from Macedonia in Europe,

but it had ruled Egypt for more than

200 years. Cleopatra and her brother,

Ptolemy XIII, became rulers together

after their father died in 51 BC. However,

her brother had followers who soon

drove Cleopatra from power.

Help from Caesar

Cleopatra went for help to Julius Caesar,

a powerful Roman ruler who was then

in Egypt. In 47 BC Caesar defeated

Ptolemy XIII’s forces, and Ptolemy died.

Cleopatra returned to the throne. Her

youngest brother, Ptolemy XIV, became

co-ruler.

Cleopatra soon followed Caesar to

Rome. She stayed there until he was

murdered in 44 BC. Ptolemy XIV died

in the same year. Cleopatra probably

had him poisoned.

Cleary used

her own twins

as the basis

for the characters

Mitch and

Amy in her

books.

Cleopatra was a queen of ancient Egypt.

She remains a symbol of beauty and power

today.

134 Clemens, Samuel Langhorne BRITANNICA STUDENT ENCYCLOPEDIA

Mark Antony

After Caesar’s death, Mark Antony

became one of the three leaders of

Rome. Cleopatra knew he could help

her to gain more power. She charmed

Antony, and he fell in love with her.

Antony eventually left his wife Octavia

to live with Cleopatra. This angered

Octavia’s brother Octavian, who later

became the emperor Augustus. He soon

declared war against Antony and Cleopatra.

Augustus defeated Antony and Cleopatra

in the battle of Actium in 31 BC.

The couple fled to Alexandria. About 10

months later, Augustus captured Alexandria.

Antony killed himself. Shortly

afterward, in 30 BC, Cleopatra also died.

According to legend, she let a poisonous

snake bite her. After Cleopatra’s death,

Egypt became a province of the Roman

Empire.

#More to explore

Augustus • Caesar, Julius • Egypt,

Ancient

Cleveland,

Grover

Elected in 1884 and again in 1892,

Grover Cleveland was both the 22nd

and the 24th president of the United

States. Cleveland was the only president

ever to be reelected after a defeat.

Early Life

Stephen Grover Cleveland was born in

Caldwell, New Jersey, on March 18,

1837. He was the son of Richard Falley

Cleveland, a Presbyterian minister, and

Ann Neal. Grover grew up in New Jersey

and later in New York State. After

his father died in 1853, Cleveland supported

his mother and sisters. In Buffalo,

New York, Cleveland worked in a

law firm. In 1859 he became a lawyer.

Political Career

Cleveland soon joined the Democratic

Party. In 1863 he became the assistant

district attorney for Erie County, New

March 18, June 24,

1837 1882 1884 1888 1892 1897 1908

Cleveland is

born in

Caldwell, New

Jersey.

Cleveland is

elected

governor of

New York.

Cleveland is

elected

president.

Cleveland loses

the presidential

election to

Benjamin

Harrison.

Cleveland

defeats

Harrison to win

a second term

as president.

Cleveland

retires.

Cleveland dies

in Princeton,

New Jersey.

T I M E L I N E

BRITANNICA STUDENT ENCYCLOPEDIA Cleveland, Grover 135

York. From 1870 to 1873 he served as

county sheriff. In 1881 he was elected

mayor of Buffalo. He became known for

attacking dishonesty in city government.

A year later Cleveland was elected governor

of New York.

In 1884 the Democrats nominated

Cleveland for the presidency.With his

reputation for honesty, Cleveland contrasted

sharply with his Republican

opponent, James G. Blaine, who was

known for political scandals. Cleveland

defeated Blaine in a close election.

First Term

President Cleveland fought corruption

and wastefulness. He hired government

employees based on their ability, not

their political loyalties. He also rejected

dishonest claims for pensions made by

CivilWar veterans. In 1887 he signed

the Interstate Commerce Act, which

established an agency to oversee the railroad

industry.

In 1886 Cleveland married Frances Folsom,

who became a popular first lady.

The couple had five children.

Cleveland ran for reelection in 1888.

His Republican opponent was

Benjamin Harrison. Cleveland received

about 100,000 more popular votes than

Harrison, but he lost in the electoral

college.

Second Term

After practicing law for four years,

Cleveland ran for president again in

1892. This time he soundly defeated

Harrison.

Cleveland now faced serious economic

and labor problems. As the United

States sank into an economic depression,

banks and businesses failed.Workers

angered by wage cuts went on strike, or

refused to work. In 1894 a strike in Chicago

against the Pullman railroad car

company turned violent. Cleveland sent

in federal troops to end the strike. That

decision lost him the support of many

workers.

Cleveland generally stayed out of foreign

affairs. He refused to make Hawaii a

U.S. territory. He also refused to help a

group of Cubans revolting against Spanish

rule.

Retirement

In 1896 the Democrats nominatedWilliam

Jennings Bryan for president instead

Grover Cleveland was the 22nd and 24th

president of the United States.

136 Cleveland, Grover BRITANNICA STUDENT ENCYCLOPEDIA

of Cleveland. The next year Cleveland

retired to Princeton, New Jersey. He

worked at Princeton University until he

died on June 24, 1908.

#More to explore

Electoral College • Harrison, Benjamin

Cliff Dwellers

#see Anasazi.

Climate

The weather found in a certain place

over a long period of time is known as

the climate. An area’s climate determines

what kinds of plants can grow

and what kinds of animals can survive

there. People use information about

climates to decide which crops to plant,

to prepare for natural disasters, and even

to choose the best season for traveling to

vacation spots.

Studying Climates

The study of climates is called climatology.

Scientists have many tools to help

in this study. They set up weather stations

on Earth to measure rainfall, temperature,

and wind speed. They send

weather balloons with special instruments

up into the atmosphere.Weather

satellites in space also report information

to scientists on the ground.

Factors That Affect Climate

Many factors affect climate. These factors

include the sun, oceans, winds, land

types, clouds, and human activities.

Sunlight affects climate by hitting Earth

unevenly. Places near the equator receive

lots of strong sunlight throughout the

year. This gives them a hot climate yearround.

Places far from the equator get

less strong sunlight, and so they are

cooler.

Oceans also affect climate. Land near an

ocean usually has a milder climate than

an inland area. The ocean warms the

land in winter and cools it in summer.

This happens because water cools and

heats more slowly than land.

Winds affect climate by carrying warm

or cool air to areas.Winds also bring

different amounts of moisture.

The type of land in an area affects the

climate, too. For example, mountain

ranges can block cold air. Also, places

that are at higher elevations are usually

cooler than nearby places at lower elevations.

Clouds affect climate by blocking the

amount of heat received from the sun

A weather balloon is released at a weather

station at the South Pole.

BRITANNICA STUDENT ENCYCLOPEDIA Climate 137

during the day. During the night, clouds

keep heat from escaping into space.

Finally, human activities may affect climate.

When people burn fuels such as

oil and coal to run cars and heat homes,

the fuels release certain gases into the air.

These gases trap heat on Earth. Some

scientists think that Earth is slowly getting

warmer and that this may be

because of the extra gases in the air. This

idea is known as global warming.

Types of Climates

No two places on Earth have exactly the

same climate. Nevertheless, many climates

are similar to one another. Some

of these general types of climates are

tropical, subtropical, cyclonic, polar, and

highland.

Tropical climates are warm all year and

have no winter. They lie near the equator.

Some tropical climates have a lot of

rain. Others are dry.

Subtropical climates are found north

and south of the tropical climates. They

have a greater range of temperatures

than tropical climates. They also may be

humid or dry.

Cyclonic climates are found mostly

north of the equator. In these climates,

cold air from the north mixes with

warm tropical air from the south. This

mixing often causes rain and snow.

Cyclonic climates usually have warmer

summers and colder winters.

Polar climates are very cold. Snow and

ice often covers the land. Some polar

areas always have a layer of frost, called

permafrost, below the soil.

Highland climates have a great range of

temperature between day and night.

They tend to be humid and cooler than

the lower lands nearby.

#More to explore

GlobalWarming •Weather

Clinton, Bill

The 42nd president of the United

States, Bill Clinton served two terms,

from 1993 to 2001. A popular leader,

Clinton oversaw a growing economy.

However, he was also the second U.S.

president to be impeached, or officially

charged with a crime. (The first was

Andrew Johnson in 1868.)

Early Life

William Jefferson Blythe III was born on

August 19, 1946, in Hope, Arkansas.

His father died in an automobile acci-

A village in northern Tunisia has warm and

sunny summers. Many people take vacations

in places with pleasant climates.

138 Clinton, Bill BRITANNICA STUDENT ENCYCLOPEDIA

dent before Bill was born. His mother,

Virginia Dell Blythe, later married

Roger Clinton, and Bill took his stepfather’s

name.

Clinton graduated from Georgetown

University inWashington, D.C., in

1968. He then attended Oxford University

in England. In 1973 he earned a law

degree from Yale University. In 1975

Clinton married Hillary Rodham, a

fellow graduate of Yale Law School.

They had one daughter.

Political Career

In 1974 Clinton ran for a seat in the

U.S. House of Representatives but lost.

Two years later he was elected attorney

general of Arkansas. In 1978 he became

governor. Clinton lost the election of

1980 but won again two years later. Voters

reelected him three more times. As

governor, Clinton reformed Arkansas’s

educational and tax systems.

Presidency

Clinton became the Democratic candidate

for president in 1992. He chose

Senator Al Gore as his vice presidential

running mate. Clinton defeated his

Republican opponent, President George

Bush. He took office in January 1993.

Clinton’s first term had many successes.

He appointed women and minorities to

August 19,

1946 1978 1992 1996 1998 1999 2001

Clinton is born

in Hope,

Arkansas.

Clinton is

elected

governor of

Arkansas.

Clinton defeats

George Bush

to win his

first term as

president.

Clinton defeats

Bob Dole to

win a second

term.

The U.S.

House of

Representatives

impeaches

Clinton.

The U.S.

Senate rules

that Clinton is

not guilty.

Clinton retires

as president.

T I M E L I N E

Bill Clinton was the 42nd president

of the United States.

BRITANNICA STUDENT ENCYCLOPEDIA Clinton, Bill 139

important posts. He oversaw a major

trade agreement between the United

States, Canada, and Mexico. He

attended peace talks between Israel and

the Palestinians in the Middle East. He

also sent U.S. peacekeeping forces to

Bosnia and Herzegovina after that

country’s civil war.

However, Clinton’s plan for a health

care system failed. He and his wife also

became linked to a business scandal

known as the Whitewater affair. Nevertheless,

Clinton defeated Republican

Bob Dole in the 1996 election. Many

people were happy with Clinton because

the economy was doing very well.

In 1998 the public learned that Clinton

had had an improper relationship with a

young worker at the White House. The

U.S. House of Representatives voted to

impeach the president, or charge him

with crimes. The House charged the

president with lying under oath and

trying to stop the investigation of the

affair. In 1999 the Senate found Clinton

not guilty.

Despite his impeachment, Clinton

remained popular. He spent his last year

as president working for peace

agreements in the Middle East and in

Northern Ireland. Clinton’s vice

president, Gore, lost the 2000 election

to the Republican candidate, George W.

Bush.

#More to explore

Bush, George • Bush, GeorgeW.

• Johnson, Andrew

Clock

A clock is a device used to tell time.

Moving hands on the face of a clock

point to the current hour, minute, and

second. A clock can be big enough to be

in a giant tower. A clock can also be

small enough to fit on a person’s wrist,

where it is called a watch. Many clocks

are made to be beautiful objects as well

as useful devices.

How ClocksWork

There are three main types of clocks:

mechanical, electrical, and atomic. All

three have the same basic parts. They

must have a source of power, a device to

keep the parts moving at regular intervals,

and a way to display the time.

Mechanical clocks get their power from

moving weights or springs. These parts

are attached to gears, or toothed wheels.

The gears are attached to the hands of

the clock. As the gears move they move

Hillary

Rodham Clinton

was the

first wife of a

sitting president

to be

elected to public

office.

The Houses of Parliament (a group of government

buildings in London) are famous

for their large clock tower. Big Ben is the

name of the bell inside the tower.

140 Clock BRITANNICA STUDENT ENCYCLOPEDIA

the hands. Another device attached to

the gears keeps them moving at a regular

pace. Mechanical clocks must be wound

up to work.

Electrical clocks get their power from

electricity instead of weights or springs.

The electricity can come from a battery

or from an electrical socket in a wall.

Some electrical clocks have hands, as

mechanical clocks do. Others have a

digital display, where the hours, minutes,

and seconds are shown as numbers.

Electrical clocks are the most common

type of clock used today.

Atomic clocks measure time using the

waves of energy given off by atoms—the

tiny bits of matter that make up the

universe. Atomic clocks normally have

digital displays. Because atomic clocks

are the most accurate type of clock, scientists

use them in their work.

History

In ancient times people measured time

by watching the position of the sun in

the sky. As the sun passed over a column

or other device it would create a shadow.

The length of the shadow would change

depending on where the sun was in the

sky. The length of a column’s shadow

therefore showed the basic time of day.

Eventually people wanted to tell time

more accurately. The first mechanical

clock was invented in the mid-1300s.

Clocks powered by coiled springs and

swinging weights were introduced in the

1500s. Clocks powered by electricity

appeared in the late 1800s and early

1900s. Atomic clocks were developed in

the 1950s.

#More to explore

Sundial • Time

Clothing

Many animals have fur, feathers, or

other natural coverings to protect them

from the weather. Humans have almost

no natural protection from the weather.

Even so, they live in some of the hottest

and coldest places on Earth. People also

have modesty, or the desire to cover

their body. In addition, each person has

a personality, a culture, and a place in

society to show to other people. For all

these reasons, people wear clothing.

Clothing Materials

Early humans made clothing from the

skins and fur of animals. When humans

Women wore long dresses and big hats in

about 1900.

BRITANNICA STUDENT ENCYCLOPEDIA Clothing 141

began to settle in villages and to grow

crops, they started making cloth from

natural fibers. Such fibers as silk and

wool came from animals. Cotton and

flax were common plant fibers.

Late in the 1800s a French chemist created

the first artificial fabric. He made

an artificial silk out of a plant fiber that

had been turned into liquid form. This

is now called rayon. In the 1930s scientists

made an even more useful material

from petroleum, or oil. It is called

nylon. Rayon, nylon, and other materials

made from chemicals may be stronger

and less likely to wrinkle or shrink

than natural cloth.

Clothing Styles

Clothing styles depend on the climate of

a region. People in a tropical rain forest

need little or no clothing. In the hot

deserts of the Middle East and North

Africa, people wear loose white robes for

protection against the sun. In the Arctic,

where it is very cold, the Inuit wear

warm furs and waterproof sealskin. In

many other regions the weather may be

hot or cold, depending on the season.

People in these regions must have both

light and heavy clothing.

People also wear clothing to tell others

about themselves. Uniforms show which

people are soldiers and police officers.

Women sometimes wear different colors

and styles than men do. Young people

may wear unusual clothes to rebel

against their parents. Rich people wear

expensive clothes made by famous

designers. Religion and culture affect

clothing styles as well. Despite these

differences, international business,

travel, movies, and television have

helped to spread similar styles around

the globe. Jeans, for example, are popular

almost everywhere.

#More to explore

Climate • Culture • Fibers

Cloud

On a sunny day a wispy cloud can be a

beautiful sight, but at other times a

cloud can be a sign of storms to come. A

Young people of the late 1980s and early

1990s wore flannel shirts and ripped jeans.

Wispy cirrus clouds drift high in the sky.

142 Cloud BRITANNICA STUDENT ENCYCLOPEDIA

cloud is made up of millions of tiny

water droplets or ice crystals floating

together in the air.

The air always contains water vapor—

water in the form of gas—which is invisible.

The amount of water vapor that air

can hold depends on the air’s temperature.

The cooler the air, the less water it

can hold. When air cools, some of the

water vapor condenses, or forms visible

water droplets. The droplets form

around tiny particles in the air, such as

dust or sea salt. Near the ground, the

condensed water vapor becomes fog. Up

in the sky, it forms clouds.

Air cools as it rises, so clouds form when

warm, moist air rises. Air is forced

upward when it blows against a moun-

Different types of clouds form at different heights.

BRITANNICA STUDENT ENCYCLOPEDIA Cloud 143

tainside. Air is also forced to rise when

the land gets very hot. Sometimes clouds

form when a cold air mass meets a

warm, moist air mass. The warm air rises

up over the cold air, causing the warm

air to cool and clouds to form. Once

clouds have formed, they will remain

until the air is warmed or rain falls.

Meteorologists (people who study

weather) classify clouds mainly by their

appearance. The three main types of

clouds are cirrus, cumulus, and stratus.

Cirrus clouds are high, thin clouds made

up of ice crystals. Cumulus clouds are

puffy clouds that are often piled up like

a mountain. Stratus clouds are layered.

Scientists combine these terms with

others—including “nimbus,” meaning

rain—to describe 10 different cloud

types. For example, cumulonimbus

clouds are huge piled-up clouds that

produce thunderstorms.

Coal

The major source of fuel throughout the

world is coal. Coal is a black or brown

rock that, when burned, releases energy

in the form of heat. One of coal’s main

uses is the production of electricity.

How Coal Formed

The coal used today began forming

about 300 million years ago. At that

time swamps with giant ferns and other

plants were common on Earth. When

these plants died, they sank in the water.

They did not completely decay, or break

down. Instead they formed a substance

called peat. Over time layers of rock and

other materials built up over the peat.

Heat and pressure hardened the peat

into coal.

Forms and Uses of Coal

Coal has several different forms. Anthracite

is hard coal. It produces the greatest

amount of heat and is used mainly for

heating homes. Bituminous coal is soft.

Power plants use it to produce electricity.

Bituminous coal is also used in steel

mills to make coke, another kind of fuel.

Lignite, the softest coal, is used to produce

gas and electricity.

Coal Mining

People get coal by mining. In one process,

called strip mining, miners take

coal from just below the surface. In deep

mining, miners dig long tunnels to get

to coal that is buried far underground.

Mining coal can be dangerous for the

miners. Coal miners can be injured or

Huge piles of coal wait to be

shipped from a port in Poland.

In the summer,

small cumulus

clouds that

appear in the

morning often

turn into dark

cumulonimbus

clouds during

the day.

144 Coal BRITANNICA STUDENT ENCYCLOPEDIA

killed when mine roofs collapse. Gases

trapped in coal sometimes cause fires or

explosions. Many miners have health

problems from breathing in coal dust

over the years.

Disadvantages of Coal

Compared to other energy resources,

coal is inexpensive and plentiful. However,

coal has several disadvantages.

Burning coal can create acid rain, a dangerous

form of pollution. Burning coal

also increases the temperature of Earth’s

atmosphere, which may be harmful to

living things. Finally, because coal takes

so long to form, it is known as a nonrenewable

resource. Eventually, Earth’s

supply of coal will run out.

#More to explore

Energy • Fossil Fuel • Mining

• Pollution

Cobra

Cobras are poisonous snakes that flatten

their necks into the shape of a hood

when they sense danger. There are several

species, or types, of cobra. Not all of

them are closely related.

Cobras live in the southern parts of Asia

and Africa. Some types dwell in grasslands,

forests, or deserts. Others live in

trees or along the shores of lakes.

Cobras are usually a single color or spotted.

They are medium to large in size.

The king cobra of Asia is the world’s

longest poisonous snake. It can reach a

length of about 18 feet (5.5 meters).

When a cobra feels threatened, it raises

up its head and extends the ribs in its

neck. This stretches the skin to create

the hood. Some types of cobra have

markings on the hood.

Cobras hunt in the evening and at

night. Their prey includes mammals,

birds, snakes, lizards, frogs, and even

fish. When cobras bite, their short front

fangs deliver venom, or poison, into the

prey. Some types of cobra can also spit

a stream of venom at the eyes of

intruders.

Some types of cobra lay eggs. Others

give birth to live young. The king cobra

builds a nest for its eggs. It also guards

the eggs until they hatch.

#More to explore

Poison • Snake

Cochise

Cochise was a chief of the Chiricahua

band of the Apache people. In the 1860s

he led a fierce fight to hold onto Apache

A black-necked cobra spreads its neck to

create a hood.

BRITANNICA STUDENT ENCYCLOPEDIA Cochise 145

lands in what is now the southwestern

United States.

Nothing is known for certain of

Cochise’s birth or early life. He was

probably born in about 1810. Through

the 1850s his people enjoyed good relations

with the U.S. government. The

peace was broken in 1861, when some

Apache stole a white rancher’s cattle and

kidnapped the son of a ranch hand. A

U.S. Army officer thought Cochise was

responsible and put him in prison along

with several other chiefs. Cochise

escaped, but the rest of the prisoners

were killed.

Cochise wanted revenge. Under his

leadership the Apache drove U.S. troops

and settlers from their land in what is

now southern Arizona. In 1863 U.S.

troops killed Mangas Coloradas, a

powerful Apache leader and Cochise’s

father-in-law. Cochise then became the

main Apache chief. He led raids against

U.S. soldiers and settlers from the

Arizona mountains until surrendering

in 1871. He escaped in 1872, but he

soon returned to Arizona and settled on

the newly created Chiricahua Reservation.

He died there on June 8, 1874.

#More to explore

Apache

Cockroach

Cockroaches are insects that have lived

on Earth for more than 320 million

years. There are more than 3,500 different

species, or types, of cockroach. Most

live in forests in warm areas. However,

some cockroaches live in warm, dark

areas of houses, apartment and office

buildings, airplanes, and ships. Cockroaches

are among the most hated

household pests.

Cockroaches have a flat, oval body that

is black or brown. For insects, they are

quite large. The common American

Cochise

Cockroaches are considered

pests because they eat people’s

food and carry diseases.

146 Cockroach BRITANNICA STUDENT ENCYCLOPEDIA

cockroach can grow to about 2 inches (5

centimeters) long. Like all insects, cockroaches

have a hard shell called an

exoskeleton. The exoskeleton protects

their soft body parts. Cockroaches have

long legs that allow them to run very

fast. Many cockroaches also have wings.

Cockroaches have well-developed senses.

They have long antennas and compound

eyes (eyes with many parts),

which help them to hunt in near darkness.

A pair of small hairs on their backside,

called cerci, can sense the slightest

movement.

Cockroaches in the wild eat rotting

plants and animals. In cities cockroaches

hide in the daytime and come out at

night to eat. They eat food scraps, paper,

clothing, and dead insects. Sometimes

the food they eat gives them a bad smell.

Cockroaches also spread several human

diseases.

#More to explore

Insect

Cod

The fish called cod are important

sources of food. People eat cod flesh as

well as the oil in their livers. Cod-liver

oil is very rich in vitamins A and D and

other things that people need to stay

healthy.

Cod live in the cold waters of the northern

Atlantic and Pacific oceans. Other

cold waters, such as the North Sea in

Europe, are also home to these fish.

The bodies of Atlantic cod are dull gray

or green with speckles. Atlantic cod may

also be reddish in color. A white line

curves from head to tail along each side.

Although smaller than Atlantic cod,

Pacific cod look very much like their

Atlantic relatives.

One unusual physical feature of the cod

is its barbel. The barbel is a thin tentacle

that hangs from the cod’s lower jaw.

Scientists think this organ may be a tool

for finding small crabs or other food

hiding in the sand.

Fishers prefer to catch cod that are 2 to

4 feet (0.6 to 1.2 meters) long. Fish this

size usually weigh 10 to 25 pounds (4.5

to 11.5 kilograms). Cod that escape

being caught may grow to be 6 feet (1.8

meters) long and more than 200 pounds

(90 kilograms) in weight.

A female cod may lay as many as 8 million

eggs. Ocean currents carry the eggs

over large areas.

#More to explore

Fish

Cod are gray-green fish with speckles. They

also have a white line on their sides.

BRITANNICA STUDENT ENCYCLOPEDIA Cod 147

Cody,William

Frederick

William Frederick Cody—better known

as Buffalo Bill—was a folk hero of the

AmericanWest. Novelists wrote about

his adventures as an Army scout and

buffalo hunter. He also produced a

famous show about theWildWest.

Cody was born in Iowa on February 26,

1846. He grew up in Kansas. At age 14

he started working for the Pony Express,

a service that delivered mail on horseback.

In the 1860s Cody served in the American

CivilWar and scouted for the U.S.

Army. As a scout he roamed around to

gather information about the Native

Americans. He also hunted buffalo

(bison). He got the nickname Buffalo

Bill for shooting thousands of buffalo to

feed railroad workers.

From 1872 to 1883 Cody acted in plays

about theWest. He also guided the U.S.

cavalry in 1874 and fought for the Army

against the Sioux in 1876.

In 1883 Cody started his WildWest

show—later known as Buffalo Bill’s

WildWest and Congress of Rough Riders

of theWorld. The show featured

trick riding, sharpshooting, and a buffalo

hunt. It toured the United States

and Europe for 30 years.

Cody used the money he made from his

show to buy land inWyoming. There he

helped found the town of Cody. He died

in Denver, Colorado, on January 10,

1917.

#More to explore

Pony Express

Coeur d’Alene

The Coeur d’Alene tribe of Native

Americans traditionally lived in what is

now northern Idaho and easternWashington.

Their name was given to them

by French traders, but they called themselves

the Schitsu’umsh. The name

means “the discovered people.”

Most of the year they lived in villages in

permanent cone-shaped houses covered

with bark and woven mats. They fished

for salmon, hunted game animals, and

gathered wild plants for food.

In the 1700s the Coeur d’Alene

obtained horses for the first time. The

men began making trips to the western

plains on horseback. There they hunted

William Frederick Cody

148 Cody, William Frederick BRITANNICA STUDENT ENCYCLOPEDIA

bison (buffalo) and traded with Plains

Indian tribes.

The Coeur d’Alene did not want traders

to enter their lands. However, they did

trade furs for metal tools, guns, and

other manufactured goods.

Like many other Native American tribes,

the Coeur d’Alene suffered from diseases

brought by European settlers. Smallpox

killed many people in the first half of

the 1800s.

In the mid-1800s the Coeur d’Alene

tried to resist settlers who wanted to take

over their territory. In 1858 a force of

1,000 Coeur d’Alene, Spokane, and

Palouse warriors fought a brief and

unsuccessful war against United States

troops. Following this defeat, the U.S.

government moved the Coeur d’Alene

to a reservation in what is now Idaho. At

the end of the 20th century about 1,500

Coeur d’Alene lived in the United

States.

#More to explore

Native Americans • Smallpox

Cold, Common

The cold is one of the most common

illnesses to affect humans. In fact, children

may get 6 to 10 colds a year. People

often catch colds during cold weather,

but chilly temperatures are not the

cause. Viruses, or tiny germs that enter

the body, cause colds. More than 200

different viruses can cause a cold.

The symptoms, or signs, of a cold generally

start two or three days after a cold

virus enters the body. Symptoms may

include a runny or stuffy nose, sneezing,

coughing, sore throat, and headache.

More than 200 different viruses

can cause the common cold.

Morris Antelope was a chief of the Coeur

d’Alene people.

BRITANNICA STUDENT ENCYCLOPEDIA Cold, Common 149

The symptoms last from a few days to

two weeks.

Cold viruses spread easily from person

to person. Coughing and sneezing force

a cold virus into the air. People may

then breathe in the virus. They may also

pick up a virus by touching surfaces

where viruses have landed. Then when

they touch their noses, the virus enters

the body.Washing one’s hands may help

to prevent the spread of cold viruses.

There is no cure for the common cold.

Treatment includes resting and drinking

lots of water, juice, or soup broth. Steam

from a hot shower or a vaporizer can

make breathing easier. Saltwater nose

drops can also help a stuffy nose. Cough

drops can soothe a sore throat. Painrelieving

medicine can ease a headache.

#More to explore

Disease, Human • Virus

ColdWar

AfterWorldWar II the United States and

the Soviet Union were the superpowers

of the world. They became rivals as they

each sought to prevent the other from

gaining too much power. The period of

tension that existed between them came

to be known as the ColdWar. The

conflict did not result in actual war

between the two countries.However, it

did lead to a number of smaller wars.

Background

During WorldWar II, the Soviet Union

freed many countries of eastern Europe

from Nazi Germany. After the war, however,

the Soviet Union continued to

control the countries. It also forced its

own Communist economic system on

them.

The United States did not want Communism

to spread to other countries in

Europe. It also wanted the western

European countries as allies, or friends.

The United States therefore gave money

to those countries to rebuild after the

war. This was called the Marshall Plan.

It was named for George Marshall, the

American who proposed the plan.

Alliances

In 1949 the United States and its European

allies formed the North Atlantic

Treaty Organization (NATO) to protect

each in case of attack. The Soviet Union

and its allies formed their own alliance,

the Warsaw Pact, in 1955.

Events of the ColdWar

Two major crises of the ColdWar

involved the German city of Berlin. At

the end ofWorldWar II the city, as well

as the country, was divided into four

zones. The United States, Britain,

In 1962 a U.S. ship (left) stops a Soviet ship

carrying missiles out of Cuba.

During the

Cold War

people in the

United States

built special

shelters to

protect themselves

from

nuclear war.

150 Cold War BRITANNICA STUDENT ENCYCLOPEDIA

France, and the Soviet Union each controlled

one of the sectors. In 1948 the

threeWestern powers announced that

they would combine their zones. The

Soviet Union then cut off road and rail

supply routes to the city, which was

completely within the Soviet part of

Germany. In response, the United States

and Britain delivered supplies by airplane.

This was the Berlin airlift. The

Soviet Union lifted its blockade in May

1949.

In the years that followed, many people

in East Berlin moved toWest Berlin to

escape control by the Soviet Union. In

1961 the Soviet Union tried to stop this

movement by building a wall around

West Berlin. The BerlinWall became a

symbol of the ColdWar.

The ColdWar soon extended beyond

Europe. The Soviet Union gave support

to other countries throughout the world

that had Communist governments. At

the same time, the United States tried to

prevent Communism from spreading

any further. Both the KoreanWar in the

1950s and the VietnamWar in the

1960s and ’70s were part of that

struggle.

Other battles took place in the countries

of theWestern Hemisphere. In 1959

Fidel Castro established a Communist

government in Cuba. In 1962, after

spotting nuclear missiles on Cuba, the

United States cut off supplies to the

island. After several tense days of the

Cuban Missile Crisis, the Soviet Union

agreed to remove the weapons.

End of the ColdWar

In the 1970s the United States and the

Soviet Union signed agreements to limit

the number of nuclear weapons that

they each had. Other changes took place

when Mikhail Gorbachev took power in

the Soviet Union in 1985. He tried to

reorganize the economic system and

encouraged glasnost, or open discussion.

In 1989 the BerlinWall was torn down.

TheWarsaw Pact was dissolved in July

1991, and later that year the Soviet

Union itself broke up into 15 separate

nations. Communist rule ended in

many countries, bringing an end to the

ColdWar.

#More to explore

Berlin • Communism • Cuba • Korean

War • North Atlantic Treaty

Organization • Union of Soviet Socialist

Republics • United States • Vietnam

War

People from East Berlin and West Berlin

gather at the Berlin Wall on November 10,

1989. The wall had been opened the day

before.

BRITANNICA STUDENT ENCYCLOPEDIA Cold War 151

Colombia

Colombia is the only country named

after Christopher Columbus. He sailed

near its Caribbean shores in the late

1400s. Colombia is located in northwestern

South America. The capital is

Bogota.

Geography

Colombia shares borders with Venezuela,

Brazil, Peru, Ecuador, and Panama.

The Caribbean Sea lies to the north, and

the Pacific Ocean is to the west.

Three ranges of the Andes Mountains

cut through the western half of Colombia.

In the east, tributaries of the Amazon

and Orinoco rivers cross a vast

plain. The country’s most important

river is the Magdalena, which flows

north into the Caribbean. The climate is

generally tropical, with warm temperatures

year-round.

Plants and Animals

Colombia has areas of mangrove swamp,

desert scrub, savanna grasslands, and

tropical rain forest. Its animal life

includes jaguars, tapirs, armadillos, ocelots,

deer, monkeys, and rare spectacled

bears. Colombia has more than 1,500

kinds of birds, ranging from the huge

Andean condor to the tiny hummingbird.

Turtles, piranhas, crocodiles, and

electric eels live in the country’s waters.

People

Nearly half of Colombians are mestizos,

or people with mixed European and

Native American roots. About one fifth

of the people have mixed African and

European roots. About the same number

of people are white. There are smaller

groups of blacks and Native Americans.

Spanish and various Indian languages

are spoken. Most of the people are

Roman Catholics. More than three

fourths of Colombians live in cities,

mostly in the west.

Economy

Colombia’s economy is based on banking

and other services, agriculture, and

manufacturing. Major crops include

sugarcane, potatoes, rice, bananas, corn,

and coffee. Some people illegally grow

coca and marijuana plants, which are

made into drugs. Colombia is also an

important cattle-producing country.

Factories make food products, beverages,

textiles, chemicals, and machinery.

152 Colombia BRITANNICA STUDENT ENCYCLOPEDIA

Colombia is rich in natural resources,

including oil, natural gas, coal, nickel,

gold, and emeralds. Oil is the top

export.

History

The first people to live in what is now

Colombia were Native Americans. The

most important group was the Chibcha.

The Spanish explorers who followed

Columbus began to conquer the area in

1525. The Spanish called the region the

Kingdom of New Granada. They forced

their language, religion, customs, and

laws on the Indians.

Late in the 1700s the Spanish colonists

in New Granada began to rebel against

Spanish rule. In 1819 New Granada

gained its independence. It became a

republic known as Gran Colombia,

which included what are now Colombia,

Panama, Venezuela, and Ecuador. In

1830 Venezuela and Ecuador left the

republic.

Colombia’s political parties, the Conservatives

and the Liberals, soon began

fighting. The conflict reached its peak in

theWar of a Thousand Days, which

lasted from 1899 to 1903. After the war

Panama gained independence from

Colombia.

Political violence broke out again in

1948. In nine years of civil war about

300,000 Colombians died. In 1957 the

Conservatives and the Liberals agreed to

share power. That agreement lasted until

1974. Since then Colombia has suffered

from violence. Much of the violence has

been caused by rebel political groups

and illegal drug traders.

..More to explore

Andes • Bogota • Columbus,

Christopher

A church in Colombia was built on a bridge

overlooking the Guaitara River.

Many coffee plants grow on a plantation,

or large farm, in Colombia. Coffee is one of

Colombia’s main crops.

Facts About

COLOMBIA

Population

(2008 estimate)

44,442,000

Area

440,762 sq mi

(1,141,568 sq

km)

Capital

Bogota

Form of

government

Republic

Major cities

Bogota, Cali,

Medellin,

Barranquilla

BRITANNICA STUDENT ENCYCLOPEDIA Colombia 153

Colombo

Population

(2004

estimate), city,

669,700; urban

area,

2,490,300

Colombo is one of the two capitals of

Sri Lanka, an island country in the

Indian Ocean. The offices of the president

and prime minister of Sri Lanka are

in Colombo. The country’s supreme

court and lawmakers meet in a nearby

suburb named Sri Jayewardenepura

Kotte.

Colombo is Sri Lanka’s largest city. It is

also the business center and leading

port. Many people in the city work in

government offices, banking, or

insurance. Colombo’s factories assemble

cars and process foods, drinks, and

tobacco.

In ancient times Colombo was a major

port for the spice trade. In 1815 the

British took control of the island.

Colombo was their capital. Sri Lanka

became an independent country in

1948. For many years Colombo was the

country’s only capital. In the late 1970s

the government decided to transfer

many departments to the nearby suburb.

..More to explore

Sri Jayewardenepura Kotte • Sri Lanka

Colony

A colony is a group of people from one

country who build a settlement in

another territory, or land. They claim

the new land for the original country,

and the original country keeps some

control over the colony. The settlement

itself is also called a colony. The practice

of setting up colonies is called colonialism.

A collection of many colonies is

called an empire.

Before about 1950 a small number of

countries controlled many colonies

around the world. But the people in the

colonies slowly gained independence as

separate countries. Today few colonies

are left.

Kinds of Colonies

Colonies are sometimes divided into two

types: settlement colonies and colonies

of occupation. People often formed

settlement colonies in places where few

other people lived. Ordinary people

moved to a settlement colony to set up

farms or run small businesses. The colonies

that the English and other Europe-

Some of Colombo’s buildings were built

during the years of British rule. Others are

modern towers.

154 Colombo BRITANNICA STUDENT ENCYCLOPEDIA

ans established in North America

beginning in the 1500s were settlement

colonies.

Countries set up colonies of occupation

by force. That is, a country conquered a

territory, and then people from that

country moved in to control it. Often

only a few wealthy people settled in this

kind of colony. India is an example of a

colony of occupation. Great Britain

controlled India from the 1800s until

1947.

Why People Set Up Colonies

One of the reasons countries formed

colonies was to make money. Countries

used colonies to control trade between

their territory and the rest of the world.

They also set up colonies to take advantage

of natural resources in new lands.

They took precious metals, timber, and

furs from the territories and sold them

to make money for themselves.

Another reason countries set up colonies

was to increase their military power.

They often set up bases for their armies

and navies in their colonies.

Still other colonies were founded as prisons.

Great Britain set up colonies in

Australia as places to send its criminals.

#More to explore

Americas, Exploration and Settlement of

the • Empire

Color

Without light, there is no color. When

people see colors, they are really seeing

different types of light bouncing off

objects.

Color and Light

Light travels in waves. Scientists use an

idea called wavelength to describe these

waves. Some light waves have long wavelengths,

while others have short wavelengths.

Light of different wavelengths

appears as different colors. For example,

A drawing shows the colony of Sydney,

Australia, in 1788. The British set up the

colony as a place to send prisoners.

Green (1), blue (2), and red (3) are the primary

colors of light. A mixture of two primary

colors of light can make cyan (4),

yellow (5), or magenta (6). A mixture of all

three makes white (7).

BRITANNICA STUDENT ENCYCLOPEDIA Color 155

red light has a long wavelength, and

violet light has a short wavelength. Normally

all the wavelengths, or colors,

travel together as white light.

When white light passes through a special

piece of glass called a prism, the

light bends. Shorter wavelengths bend

more than longer wavelengths. This

bending causes the white light to separate

into the colors of the rainbow.

White light also separates into different

colors when it strikes objects. For

example, when white light strikes a ripe

tomato, mostly red wavelengths reflect,

or bounce, off the tomato. The tomato

absorbs, or takes in, all the other colors.

This causes the tomato to look red.

Mixing Colors

Three colors of light—red, blue, and

green—can combine to make any other

color. For example, if a beam of green

light shines over a beam of red light,

yellow light appears. Red, blue, and

green are called primary colors of light.

Mixtures of the primary colors of light

produce all the other colors.

To make colors appear in printed

books, people use inks. Inks, paints,

dyes, and crayons get their color from

pigments, or substances that reflect

certain colors of light. The three

primary colors of pigments are magenta

(a purplish red), yellow, and cyan (a

blue-green). Different mixtures of these

colors can make all other colors. For

example, mixing cyan ink and yellow

ink makes green ink.

Seeing Color

Cells in the eyes called cones make it

possible for humans to see color. Different

types of cones absorb different colors.

Some people are color blind. This

does not necessarily mean that they cannot

see any color at all. More commonly,

people with color blindness

think certain colors, such as red and

green, look the same.

Colors can tell animals about their surroundings.

Color attracts insects to flowers

where they can get food. It can show

when fruits are ripe and ready to eat.

Color can also help certain plants and

animals survive. For example, some animals

have colors that are similar to the

habitat in which they live. This helps

them hide from other animals that may

want to attack them.

#More to explore

Light • Prism • Protective Coloration

• Rainbow

Yellow (1), cyan (2), and magenta (3) are

the primary colors of pigments, or inks. A

mixture of two primary colors of pigments

can make green (4), red (5), or blue (6). A

mixture of all three makes black (7).

156 Color BRITANNICA STUDENT ENCYCLOPEDIA

Colorado

The state of Colorado got its name from

the Spanish word meaning “red.” Spanish

explorers gave the name to the Colorado

River because of its brightly

colored water, and later the name was

used for the land as well. Colorado is

nicknamed the Centennial State because

it joined the Union in 1876—100 years

after the signing of the Declaration of

Independence. Denver is the state’s capital

and largest city.

Geography

Colorado is in the western United

States. It borders Nebraska on the northeast,

Wyoming on the north, Utah on

the west, New Mexico and Oklahoma

on the south, and Kansas on the east.

The Rocky Mountains cover about half

of Colorado, stretching from the northwest

to the south-central part of the

state. The highest peak is Mount Elbert

at 14,433 feet (4,399 meters). Eastern

Colorado is part of the Great Plains.

Much of western Colorado is an area of

flat-topped hills (mesas) and steepwalled

canyons.

People

More than four fifths of Colorado’s

residents are whites of European

descent. Hispanics, mainly Mexicans,

make up the largest minority. The

numbers of African Americans and

Native Americans are small. Members

of the Ute tribe live on two reservations

in the southwest.

Most of Colorado’s people live

along the eastern edge of the

mountains, an area of towns and

cities that runs from Fort Collins in the

north to Pueblo in the south. Denver,

Boulder, Greeley, and Colorado Springs

are major cities in this area.

Economy

Mining and agriculture have been major

parts of Colorado’s economy since the

frontier days. Today the state’s mineral

wealth includes petroleum (oil), coal,

molybdenum, sand, and gravel. The

largest source of farm income is cattle

raising, though many sheep and hogs

also are raised. The main crops are

wheat, hay, and corn.

Tourism, manufacturing, and hightechnology

industries became valuable

in the 1900s. Major manufacturing

industries include food processing and

BRITANNICA STUDENT ENCYCLOPEDIA Colorado 157

the production of computer and electronics

equipment, metals, and military

weapons.

History

Native Americans known as the Anasazi

lived in the Colorado area from about AD

100 to 1300.Mesa Verde National Park

in southwestern Colorado preserves

ruins of their cliff dwellings. Spaniards

first explored the area in the mid-1500s.

Spanish and French explorers who

visited in the 1700s met Plains Indian

tribes such as the Cheyenne, the

Arapaho, the Comanche, and the Kiowa.

In 1803 the United States bought the

plains portion of Colorado as part of the

Louisiana Purchase, a land deal with

France. The United States took control

of much of the rest of Colorado after

winning a war against Mexico in the

mid-1800s. After gold was discovered in

1859, miners and other settlers arrived

from the East. The U.S. Congress created

the Colorado Territory in 1861. In

1876 Colorado became a state.

DuringWorldWar II the U.S. government

began building military bases and

other facilities in Colorado. Many of the

people who came to Colorado for work

stayed after the war. Later, the creation

of ski resorts helped make tourism a

leading industry.

..More to explore

Anasazi • Colorado River • Denver

• Rocky Mountains

The Cliff Palace in Mesa Verde National Park, Colorado, has about 200 rooms. The Anasazi

people built the cliff dwellings about 800 years ago.

Facts About

COLORADO

Flag

Population

(2000 census)

4,301,261—

rank, 24th state;

(2008 estimate)

4,939,456—

rank, 22nd state

Capital

Denver

Area

104,094 sq mi

(269,601 sq

km)—rank, 8th

state

Statehood

August 1, 1876

Motto

Nil Sine Numine

(Nothing Without

Providence)

State bird

Lark bunting

State flower

Rocky Mountain

columbine

158 Colorado BRITANNICA STUDENT ENCYCLOPEDIA

Colorado River

The Colorado River flows from Colorado

southwest through the Rocky

Mountains and into Mexico. There it

drains into the Gulf of California, an

arm of the Pacific Ocean. The river’s

most famous landmark is the Grand

Canyon in Arizona. The mighty flow of

the Colorado River carved out this huge

canyon millions of years ago.

The Colorado River begins as a series of

small streams in northern Colorado. For

much of its length of 1,450 miles (2,330

kilometers), it is only a narrow passage

through deserts. By the time it gets to

the ocean, nearly all of its water has been

used up.

People use much of this water. The river

has several dams. It is connected to

many canals. Along its course, a number

of power plants use the water to create

electricity. But the Colorado also loses

more water through evaporation than it

receives from rivers that flow into it.

Elk, bear, and moose are some of the

many animals living along the Colorado

River. Many different kinds of fish swim

in its waters. The plants that grow near

the river include cottonwood trees, columbine

flowers, and prickly pear cacti.

Long before Europeans arrived in the

area, Native American groups farmed

along the Colorado River. Their farms

were some of the earliest in North

America. Spanish explorers discovered

the lower Colorado River in the 1500s.

Many people today argue over how the

Colorado River should be used. Several

Western states and Mexico need its

waters. This competition has led to legal

battles. The ways in which people use

the water have also created problems.

One such problem is that the power

plants and other human projects have

polluted the water.

#More to explore

Canal • Dam • Grand Canyon

The Colorado River cuts through Marble

Canyon in Grand Canyon National Park.

BRITANNICA STUDENT ENCYCLOPEDIA Colorado River 159

Columbia

Population

(2000 census),

city, 116,278;

(2007 estimate)

124,818

Columbia is the capital of the U.S. state

of South Carolina. The city lies in the

center of the state on the Congaree River.

Columbia is a center for supplying

goods to surrounding areas. Factories in

the city make cloth, steel, electrical

equipment, and other products. Many

people work for the government or in

education. The University of South

Carolina and several other universities

are located there.

In 1786 the state government decided to

move the capital from Charleston.

Columbia was built to be the new capital.

In the 1860s, during the American

CivilWar, many Confederate offices

were located in Columbia. In 1865

Union troops took over the city. A fire

then almost destroyed Columbia. After

the war the city was rebuilt.

..More to explore

South Carolina

Columbia River

The Columbia River is a major river

that flows through Canada and the

northwestern United States. The

Columbia is about 1,240 miles (2,000

kilometers) long. It empties into the

Pacific Ocean.

So many dams have been built along the

Columbia that it has been called the

Electric River. Dams produce hydroelectric

power, or electricity that comes from

intense water pressure. Together the

Columbia River dams create almost one

third of the hydroelectric power produced

in the United States.

The Columbia River begins in Columbia

Lake, in the Rocky Mountains in

British Columbia, Canada. It passes

Columbia, South Carolina, is a historic city

with many old buildings.

160 Columbia BRITANNICA STUDENT ENCYCLOPEDIA

through the mountains and flows south

intoWashington State. In southern

Washington the river turns west. It then

flows to the Pacific while forming the

border betweenWashington and

Oregon. In this area it passes through

the Cascade Mountains, where it forms

the deep Columbia River Gorge.

Near the river’s mouth heavy rains help

evergreen forests grow. Farther inland

the climate is drier. Pine, fir, and larch

trees grow in the mountains where the

river starts.

The Columbia was once filled with

salmon. Now their numbers are greatly

reduced. The dams have caused this

change. But millions of water birds live

in the surrounding wetlands. Deer,

bears, and bighorn sheep are also common

along the Columbia.

Native Americans have lived along the

Columbia for centuries. European

explorers first saw the river in 1775. The

Lewis and Clark Expedition followed

part of the river in 1805 after the United

States claimed the area.

..More to explore

Dam • Lewis and Clark Expedition

• River

Columbus

Population

(2000 census),

city, 711,470;

(2007 estimate)

747,755

Columbus is the capital of the U.S. state

of Ohio. It is the largest city in the state.

The Scioto River flows through the

downtown area.

Many people in the city work for the

government. Others work in banking,

insurance, health care, research, or education.

Ohio State University and several

colleges are in Columbus. Factories in

the city make cars and machinery.

Columbus was built in the early 1800s

to be the new capital of Ohio. The state

government offices were moved there

from Chillicothe by 1816. The city grew

as a transportation center.

In the years before the American Civil

War Columbus was a place where

escaped slaves could go to for safety and

help. During the war captured Confederate

soldiers were kept as prisoners in a

camp in the city.

The Columbia River passes through the Cascade

Mountains, where it forms the Columbia

River Gorge.

BRITANNICA STUDENT ENCYCLOPEDIA Columbus 161

Many new factories were built in

Columbus after 1940. The city began to

grow greatly in the late 20th century.

#More to explore

Ohio

Columbus,

Christopher

Christopher Columbus opened the

world of the Americas to his fellow

Europeans. Europeans called Vikings

had reached the Americas hundreds of

years before Columbus first arrived

there in 1492. However, the Vikings

did not establish long-lasting

settlements. Columbus explored the

area and brought back more Europeans

with him on later trips. Columbus’

voyages therefore had many more

lasting effects.

Columbus began an unstoppable wave

of European settlement in the Americas.

This settlement brought European culture

to theWestern Hemisphere. It also

brought great hardship to the Native

Americans there. They suffered from

diseases brought by the Europeans. They

were also enslaved and forced to mine

gold for the Europeans.

Early Life

Cristoforo Colombo was born in Genoa,

Italy, in 1451. He is known as Christopher

Columbus to English-speaking

people. He was the son of a weaver and

had little schooling.

In about 1476 Columbus settled in Portugal.

In the 1480s he started planning a

voyage to discover a sea route to Asia.

Europeans were eager for Asian goods.

However, these goods were costly

because they had to be brought to

Europe over a dangerous land route.

Columbus knew that Earth was round.

He thought that Asia must lie to the

west, across the Atlantic Ocean.

The Portuguese king refused to pay for

Columbus’ voyage. Columbus then

The city of Columbus, Ohio, overlooks the

Scioto River.

Christopher Columbus

162 Columbus, Christopher BRITANNICA STUDENT ENCYCLOPEDIA

lost all four of his ships. He had to be

rescued.

Last Years

Columbus returned to Spain in November

1504. He died on May 20, 1506.

Until his death he remained convinced

that he had reached Asia.

#More to explore

Americas, Exploration and Settlement of

the • Exploration • Ferdinand and

Isabella • Native Americans

Comanche

The Comanche people are a Native

American tribe that once roamed the

southern Great Plains of North America.

They were one of the first tribes to use

horses extensively. Horses eventually

changed the way that all Plains Indians

lived.

The Comanche were originally a branch

of the Shoshone people ofWyoming.

The Comanche moved southward in

stages, attacking and displacing other

Plains tribes.

The Comanche got horses from the

Spanish in the 1600s. They became

skilled horse breeders. The Comanche

used their horses to hunt bison (buffalo).

Their main source of food was

bison meat, and they used the animals’

hides for clothing and as coverings for

their tepees.

During their travels the Comanche

introduced the use of horses to other

tribes. By the early 1800s the

Comanche had become a powerful

tribe.

In the mid-1800s the southern branch

of the Comanche were settled on a reservation

in the Indian Territory (now

Oklahoma). The northern branch of the

tribe fought to protect its hunting

grounds against white settlers. Many

people were killed in violent battles

between the Comanche and U.S. troops.

The Comanche lost most of their land.

In the late 20th century about 10,000

Comanche lived in the United States.

About 3,000 of them lived on private

lands in the area of Lawton, Oklahoma.

#More to explore

Native Americans • Shoshone

Quanah Parker was a

Comanche chief of the late

1800s and early 1900s.

164 Comanche BRITANNICA STUDENT ENCYCLOPEDIA

Combustion

Combustion is a chemical reaction that

produces heat and light. The most

common form of combustion is fire.

Most forms of combustion happen

when the gas oxygen joins with another

substance. For example, when wood

burns, oxygen in the air joins with

carbon in wood.

Many common substances can undergo

combustion—for example, paper, cloth,

and natural gas. Combustion begins

when the substance reaches a temperature

called its ignition point. At this

temperature oxygen combines with the

substance fast enough to produce a

flame. Different substances have different

ignition points. For example, the

ignition point of paper is about 451° F

(233° C).

A substance may reach its ignition point

by being heated, struck by a spark, or

exposed to strong light. For example, a

hot match can raise the temperature of a

piece of paper to its ignition point. A

spark can do the same thing. So can

sunlight that is focused through a magnifying

glass.

Very fast combustion can cause an

explosion. This type of combustion happens

in a bomb or a firecracker. During

an explosion air heats up so fast that it

expands and moves outward with great

force.

#More to explore

Bomb • Chemistry • Fire

Comet

A comet is a small chunk of dust and ice

that orbits, or travels around, the sun. It

is sometimes described as a “dirty snowball.”

There are billions of comets in the

solar system, but most never pass close

by Earth. The best-known comet is

A bomb explodes in military

training. During an explosion air

expands and moves outward

with great force.

A shining comet streaks across the sky.

BRITANNICA STUDENT ENCYCLOPEDIA Comet 165

called Halley’s Comet. It can be seen

from Earth about every 76 years.

Orbit

Most planets orbit the sun in a path

shaped like a circle. On the other hand,

a comet’s orbit is shaped like a long oval.

Most comets travel very far into the

outer solar system as they orbit.

Depending on the comet, it can take

from several years to many thousands of

years to complete one orbit.

Earth passes through the orbit of some

comets. Bits of dust left behind by the

comets crash into the gases surrounding

Earth. They burn up in the sky in what

is called a meteor shower.

Parts of a Comet

The main part of a comet is called the

nucleus. It is made of frozen water and

gases plus dust and rock. The nucleus

usually measures a few miles across.

Most of the time a comet consists of

only its nucleus. However, when the

comet gets close to the sun, the sun’s

heat causes it to shed gas and dust. A

huge cloud of gas and dust called a coma

builds up around the comet. The coma

is sometimes larger than Earth. It makes

the head of the comet look blurry.

When a comet moves even closer to the

sun it grows tails. This happens because

the sun gives off energy and streams of

particles. They push some of the coma’s

dust and gases out into long streams.

Comet tails can be very long—as long as

the distance from Earth to the sun. The

coma and tails last only while the comet

is fairly close to the sun.

#More to explore

Meteor and Meteorite • Solar System

• Sun

Communication

People learn and share information

through communication. All forms of

communication have one thing in common:

the sending and receiving of a

message. Using different kinds of communication,

people can pass along their

ideas and feelings to just one person or

to millions.

Communication is not only a human

activity. Animals communicate through

sounds, scents, and acts. Computers

communicate with other computers

through electronic networks.

People can quickly and easily

communicate with one another

over long distances using computers

and cell phones.

Halley’s Comet

passes by

Earth every

76 years.

It is named

for Edmond

Halley, an

English

astronomer

who predicted

one of its

appearances.

166 Communication BRITANNICA STUDENT ENCYCLOPEDIA

Kinds of Communication

People communicate through language,

both spoken and written. Spoken language

includes conversations and

speeches.Written language includes

books, newspapers, and e-mail.

People also communicate without

words. Body and face movements show

feelings. Deaf people use hand movements

called sign language.

The arts are also a form of communication.

Photographs, paintings, music, and

movies can communicate feelings as well

as facts.

History

The first modern humans appeared

about 200,000 years ago. They likely

used sounds, movements, and then

speech. About 30,000 years ago humans

started making paintings and sculptures

on the walls of caves.

Humans invented writing more than

5,000 years ago. The ancient Sumerian

people developed the first known script,

called cuneiform. Then the ancient

Egyptians developed a picture-based

writing called hieroglyphics. The invention

of the printing press in the 1400s

was a major advance in written communication.

It let printers quickly make

copies of a text.

Telecommunication is communication

over long distances. In ancient times

pigeons carried written messages. Before

trains and cars, messengers on foot or on

horseback carried letters. Public postal

services started in the 1500s and 1600s.

Since then, telecommunication has

become faster thanks to television, telephones,

and the Internet.

#More to explore

Arts • Language • Sign Language

• Telecommunication •Writing

Communism

Communism is a type of government as

well as an economic system (a way of

creating and sharing wealth). In a Communist

system, individual people do not

own land, factories, or machinery.

Instead, the government or the whole

community owns these things. Everyone

is supposed to share the wealth that they

create.

Karl Marx

By the 1800s many countries followed

the economic system called capitalism.

Under capitalism, individual people,

called capitalists, own property and run

companies. Some capitalists became rich

but paid their workers very little. In

response, many workers began supporting

the ideas of socialism. In a socialist

Two songbirds—a female and a male—

communicate with one another by singing.

Birds can send a variety of messages, such

as interest in mating, through their songs.

BRITANNICA STUDENT ENCYCLOPEDIA Communism 167

system, the government owns companies

and divides wealth more fairly among

the people. Karl Marx, a German

thinker of the 1800s, took socialist ideas

one step further. Marx’s ideas became

the basis of Communism.

Marx called the workers the proletariat.

Marx thought that some day the workers

would lead a revolution and overthrow

the capitalists. After taking

control, the proletariat would become

the new ruling class. At first there would

be a “dictatorship of the proletariat” to

defeat all opposition. Then a true Communist

society would develop. This

would include common ownership of

property and no government. People

would work to produce wealth according

to their abilities. Everyone would

share in this wealth according to their

needs.

Communist Governments

The Russian Revolution of 1917

brought the first Communist government

into power. Vladimir Lenin set up

a political party to put Marx’s ideas into

practice. This party, later called the

Communist Party, organized a new

country named the Soviet Union.

AfterWorldWar II ended in 1945, the

Soviet Union forced many countries in

eastern Europe to set up Communist

governments. The United States and its

allies opposed the spread of Communism.

A rivalry called the ColdWar

developed between the two sides.

Communists took control of China in

1949. Communism then spread to other

parts of Asia (Vietnam, Cambodia,

North Korea), Africa (Ethiopia and

Angola), and Central America (Cuba

and Nicaragua).

None of these countries ever achieved a

true Communist society like Marx had

described. Instead of having no government,

they all had very strong, strict

governments. Plus, their governmentrun

economies did poorly. Between

1989 and 1991 the Communist governments

in the Soviet Union and eastern

Europe collapsed. China’s Communist

government ruled into the 21st century.

But China also took some steps toward a

capitalist system.

#More to explore

Capitalism • China • ColdWar

• Economics • Lenin, Vladimir Ilich

• Russian Revolution • Socialism

• Union of Soviet Socialist Republics

Karl Marx did

not like religion.

This

prejudice

made many

religious

people dislike

Communism.

Karl Marx is often called the Father of Communism.

168 Communism BRITANNICA STUDENT ENCYCLOPEDIA

Comoros

Three volcanic islands make up the

Union of the Comoros, a tropical country

off the east coast of Africa. The capital

is Moroni, located on the island of

Ngazidja.

Geography

Comoros includes the islands of

Ngazidja (Grande Comore), Mwali

(Moheli), and Nzwani (Anjouan). The

island of Mayotte, to the southeast, is a

French territory. The islands lie in the

Indian Ocean between Mozambique, a

country in southeastern Africa, and

Madagascar, a much larger island country.

Volcanoes formed the islands, which

are all mountainous. The climate is hot,

with dry and humid seasons.

Plants and Animals

The islands contain lush tropical rain

forests. Coconut palms and mangrove

trees grow along the beaches. Among

Comoros’ animals are rare bats, birds,

and lemurs. In the waters live coelacanths,

fish that scientists once thought

were extinct.

People

Most Comorans have a mixture of African,

Arab, Malay, and Indonesian roots.

The majority of people are Muslims.

The official languages are Comorian,

Arabic, and French. Comorian is similar

to Swahili, a language spoken in East

Africa. About two thirds of the population

lives in rural areas.

Economy

Comoros is a poor country. Agriculture

and fishing are the most important parts

of the economy. Crops include coconuts,

bananas, cassava, rice, cloves,

vanilla, and ylang-ylang (blossoms used

in perfume). Trade and tourism are also

important. Small manufacturers make

perfume, cement, soaps, wood products,

and clothing.

History

People have lived on the islands since

about AD 500. Arab traders later settled

there. The Comorans grew rich by selling

slaves, sugar, and cloves. France took

control of the islands in the 1800s.

Comoros gained independence in 1975,

but its government was not stable for

many years. In 2001 a new constitution

gave each island more power to govern

its own people.

..More to explore

Madagascar • Moroni

Facts About

COMOROS

Population

(2008 estimate)

645,000

Area

719 sq mi (1,862

sq km)

Capital

Moroni

Form of

government

Federal republic

Major cities

Moroni, Mutsamudu,

Domoni,

Fomboni

BRITANNICA STUDENT ENCYCLOPEDIA Comoros 169

directions. To use a compass, a person

lines up the needle with the marking

for north. Then the person can figure

out all the other directions.

A compass works because Earth is a

huge magnet. A magnet has two main

centers of force, called poles—one at

each end. Lines of magnetic force connect

these poles. Bits of metal near a

magnet always arrange themselves along

these lines. A compass needle acts like

these bits of metal. It points north

because it lines up with Earth’s lines of

magnetic force.

Earth’s magnetic poles are not the same

as the geographic North and South

poles. The geographic poles are located

at the very top and bottom of a globe.

The magnetic poles are nearby but not

at exactly the same places. A compass

points to the magnetic North Pole, not

the geographic North Pole. Therefore, a

compass user has to make adjustments

to find true north.

A special kind of compass called a gyrocompass

does point to true north. The

gyrocompass uses a device called a gyroscope,

which always points in the same

direction. Today large ships carry both

magnetic compasses and gyrocompasses.

People in China and Europe first learned

how to make magnetic compasses during

the 1100s. They discovered that

when a magnetized bit of iron floated in

water, it pointed north. Sailors soon

began to use compasses to navigate, or

find their way, at sea.

#More to explore

Gyroscope • Magnet and Magnetism

• Navigation

Computer

A computer is a device for working with

information. The information can be

Students use a computer in a

classroom.

People camping in the woods sometimes

carry pocket compasses so they do not get

lost.

BRITANNICA STUDENT ENCYCLOPEDIA Computer 171

The programs and data are kept permanently

on hardware called storage

devices. Most computers have a storage

device called a hard drive. The hard

drive stores data on a metal disk inside

the computer. Some storage devices put

data on disks that can be easily moved

from one computer to another. These

disks include CDs and DVDs. They

make it easy to share data.

Input and output devices are other types

of hardware. Input devices let the user

enter data or commands into the computer.

Input devices include the keyboard

and the mouse. Output devices let

the user see or hear the results produced

by the computer. Output devices

include the monitor (or screen), printer,

and speakers.

Communication, or network, devices

connect computers to each other. They

let people send data from one computer

to another and connect to the Internet.

Modems are communication devices

that can send data through telephone

wires or television cables. Some computers

use wireless communication devices.

They send data through the air using a

small antenna.

Computer software is divided into two

basic types—the operating system and

application software. The operating system

controls how the different parts of

hardware work together. Application

software gives the computer instructions

for doing specific tasks, such as word

processing or playing games.

How ComputersWork

Most computers are electronic devices.

This means that they work with electricity.

All computer data is carried in tiny

flows of electricity called electric currents.

The microprocessor contains

thousands or millions of tiny electronic

parts called transistors. The transistors

act as switches. They control how the

electric currents flow.

Computers use these electric currents to

represent the numbers 0 and 1. Computers

use only these two numbers

because transistors, like light switches,

have only two states—they are either on

or off. A transistor that is “on” represents

one of the numbers. A transistor that is

“off ” represents the other. Computers

use strings of 0s and 1s to stand for letters,

sounds, and all of the other data

they handle. For example, a computer

stores the word dog as three numbers:

01100100 (d), 01101111 (o), and

01100111 (g).

Computers can understand only these

patterns of 0s and 1s. All of the instructions

that a computer follows have to be

in this form. But people find it hard to

work with long number patterns. So the

people who write computer software,

called computer programmers, have

their own special languages. These

include programming languages called

BASIC, Java, and C++. The computer

turns programming languages into the

number patterns that it can understand.

History

An English inventor named Charles

Babbage designed the first computer in

An English

woman named

Ada Lovelace

studied Babbage’s

machine and

explained how

it could be

used to solve

problems. She

is called the

first computer

programmer.

BRITANNICA STUDENT ENCYCLOPEDIA Computer 173

the 1830s. It was mechanical, not electronic,

because scientists did not yet

know how electricity worked. The

design called for more than 50,000

moving parts. The machine was

designed to follow instructions that

people entered using punched cards. It

was so complex that Babbage never got

it built. But it is still considered to be

the first computer.

The first electronic computers were

invented in the 1940s. In place of

mechanical parts, they used electronic

switching devices called vacuum tubes.

These computers were so big that just

one of them filled a whole room. They

cost millions of dollars.

Computers improved after the

transistor was invented in 1947. The

transistor was an electronic switching

device that was much smaller and

worked better than a vacuum tube. By

1960 transistors had mostly replaced

vacuum tubes in computers. The new

computers were smaller and more

affordable than before.

The first computers with microprocessors

appeared in the early 1970s. A

microprocessor had many tiny transistors

on one small wafer, or chip. It made

personal computers possible. As more

transistors were included in microprocessors,

computers became faster and

less expensive.

#More to explore

Electricity • Electronic Games

• Electronics • Internet

Conakry

Population

(2004 estimate)

1,851,800

Conakry is the capital of theWest African

country of Guinea. It is the country’s

only large city. Part of Conakry is

on Tombo Island in the Atlantic Ocean.

The rest of the city is on the mainland

of Africa. A raised roadway connects the

city’s two parts.

Shipping brings money to Conakry.

The city is Guinea’s main port.

Government jobs and business services

The most powerful

computers

are called

supercomputers.

The fastest

supercomputers

of the 21st

century can do

trillions of calculations

per

second.

Computer chips are tiny but they can work

with a large amount of information very

quickly.

174 Conakry BRITANNICA STUDENT ENCYCLOPEDIA

are important to the economy. Conakry

is also the country’s center of industry.

A people known as the Susu lived in the

Conakry area before Europeans arrived.

French traders and soldiers took over

Tombo Island in the 1880s. Their settlement

later became the capital of the

colony of French Guinea. In 1958

Guinea became an independent country

with Conakry as its capital.

..More to explore

Guinea

Concord

Population

(2000 census)

40,687; (2007

estimate)

42,392

Concord is the capital of the U.S. state

of New Hampshire. The city lies on the

Merrimack River.

Many people in Concord work for the

government. Others work in health care,

insurance, and other service industries.

Factories in the city make electronic

equipment and other products.

The site of Concord was settled in 1727.

It was named Penacook Plantation and

later Rumford. The city was part of

Massachusetts for several years. It

became Concord, New Hampshire, in

1765. Concord became the capital of

New Hampshire in 1808.

The State House of New Hampshire

was built in Concord with granite from

a nearby mine. For many years

Concord granite was a popular building

material.

..More to explore

New Hampshire

Concrete

Concrete is the world’s most widely

used building material. Concrete is an

artificial, or man-made, stone. It is

strong and long lasting. It can be made

into almost any shape. Concrete is used

to make driveways, patios, roads,

bridges, and even entire buildings.

How Concrete Is Made

One of the main ingredients of concrete

is a fine powder called cement. Concrete

The State House of New Hampshire in Concord

was built with local granite.

BRITANNICA STUDENT ENCYCLOPEDIA Concrete 175

is made by mixing cement with sand,

gravel, and water. The water and cement

form a thick paste that holds the sand

and gravel together. The water also

causes a chemical reaction that makes

the mixture dry and harden. Before concrete

dries it can be poured into forms to

make many different shapes, including

blocks, bricks, flat slabs, and arches.

After the concrete dries, it lasts a very

long time.

Advantages of Concrete

Concrete does not burn and it stays

strong during a fire. Materials can also

be added to make the concrete stand up

to heat, water, or chemicals. It can be

made light or heavy in weight. Some

types of concrete will even harden

underwater.

Concrete with metal bars running

through it is called reinforced concrete.

It is even stronger than regular concrete

and can support heavy loads. Reinforced

concrete is used to make roads, bridges,

and very tall buildings.

History

Concrete has been around for a long

time. Thousands of years ago the ancient

Babylonians used clay to hold sand and

gravel together. Ancient Romans used

ash from a volcano to make the concrete.

The ash, when mixed with water,

acted like glue, just like modern cement

does. The Romans used concrete to

build their domes, aqueducts, and

bridges. In the 1800s cement was

invented and became the main ingredient

in concrete.

#More to explore

Cement

Condensation

#see Evaporation and

Condensation.

Confederate

States of America

The Confederate States of America was

formed after Abraham Lincoln was

elected president of the United States in

November 1860. Lincoln was against

slavery. For many people in the Southern

states slavery was a part of their way

of life. They were afraid that the new

government would end slavery and

make them give up that way of life.

Therefore a group of these states withdrew

from the United States and formed

their own government. To defend this

government they fought the American

CivilWar from 1861 to 1865.

A construction worker moves a slab of concrete.

The metal bars in the concrete make it

especially strong.

176 Condensation BRITANNICA STUDENT ENCYCLOPEDIA

Member States

The first states to withdraw from the

Union were Alabama, Florida, Georgia,

Louisiana, Mississippi, and South Carolina.

Representatives from these states

organized the Confederate States, or

Confederacy, on February 4, 1861.

Texas joined a month later. After the

first shots of the war were fired, Arkansas,

North Carolina, Tennessee, and

Virginia also joined. Part of Virginia

later decided to split off and form the

new state ofWest Virginia. That state

joined the United States in 1863. Other

slaveholding states stayed in the Union.

Organization

Jefferson Davis of Mississippi was

elected president of the Confederacy,

and Richmond, Virginia, was made the

permanent capital. The government

ordered a flag to be created and issued

postage stamps and money. The Confederate

States had a constitution similar to

the U.S. constitution. The government

was also organized into branches and

departments much like those of the

United States.

The CivilWar

After withdrawing from the Union, the

Confederate States took possession of

the forts and other public property of

the United States lying within their borders.

U.S. troops, however, continued to

occupy Fort Sumter, located in the harbor

off Charleston, South Carolina. On

April 12, 1861, the Confederacy opened

A map shows how the issue of slavery divided the United States.

BRITANNICA STUDENT ENCYCLOPEDIA Confederate States of America 177

fire on the fort. On April 14 the Union

troops surrendered. The next day President

Lincoln called for troops to be used

against the Confederate States. This was

the beginning of the CivilWar.

End of the Confederacy

The Confederacy had some advantages

in the CivilWar. It was defending its

own territory, and it had brilliant generals.

However, the Confederacy had only

about 5.5 million citizens (and 3.5 million

slaves). There were 22 million

Northerners. The Confederacy also had

few factories to produce the goods it

needed to survive. After four years of

fighting, Confederate forces surrendered

on April 9, 1865.

#More to explore

American CivilWar • Davis, Jefferson

Confucius

For more than 2,000 years the people of

China have been guided by the principles

of the teacher and philosopher

Confucius. His teachings, known as

Confucianism, are based on kindness,

love, and respect. Confucianism serves

as a way of life, a source of values, and a

social code for its followers.

Confucius was born in 551 BC in Qufu,

in what is now China’s Shantung Province.

His exact birthday is not known,

though many people in eastern Asia

celebrate it on September 28. Confucius

is not his original name. His family

name was Kong. Confucius is a European

version of the Chinese name Kongfuzi,

meaning “Master Kong.”

Confucius was a good student in his

youth. He studied many subjects,

including ceremonial practices, music,

archery, driving a chariot, calligraphy,

and arithmetic. He also had a good

understanding of history and poetry.

While in his 30s Confucius began teaching.

His goal was to improve society. He

believed that students should work on

bettering their lives in addition to gaining

knowledge.

Confucius was also concerned with

politics. He wanted an influential

position in the government so that he

would be able to reform society. He

held government posts while in his 40s

and 50s, but he never received a

position of great influence. Confucius

died in 479 BC.

#More to explore

China

The Chinese teacher and philosopher

Confucius is pictured in

a painting from the 1700s.

178 Confucius BRITANNICA STUDENT ENCYCLOPEDIA

Congo, Democratic

Republic of the

Located along the equator in Central

Africa, the Democratic Republic of the

Congo is the third largest country on

the continent. Its capital and largest city

is Kinshasa.

Geography

The Democratic Republic of the Congo

shares borders with the Central African

Republic, Sudan, Uganda, Rwanda,

Burundi, Tanzania, Zambia, Angola,

and the Republic of the Congo. The

western tip of the country touches the

Atlantic Ocean.

The Congo River flows through the

country and along its western border.

High plateaus border the plains around

the river. Three chains of mountains run

through the east. Margherita Peak, at

16,795 feet (5,119 meters), is the country’s

highest point. Most of the country

is hot and humid.

Plants and Animals

Rain forests of mahogany, ebony, and

other trees grow in the Congo river

basin. Mangrove trees grow in swamps

near the coast. Grasslands cover the eastern

plateaus.

The country’s many wild animals

include chimpanzees, monkeys,

elephants, lions, cheetahs, hyenas, buffalo,

antelope, rhinoceroses, and giraffes.

Gorillas live in the eastern mountains.

Hippopotamuses and crocodiles inhabit

rivers and lakes.

People

The people of the Democratic Republic

of the Congo belong to many different

ethnic groups. The major groups are

the Luba, the Kongo, and the Mongo.

French and English are the official

languages, but many people speak

Lingala or one of 200 other languages.

Most of the people practice Christianity.

The rest follow traditional

African beliefs or other religions. More

than two thirds of the people live in

small towns and villages.

Economy

Most of the people are farmers. Main

crops include cassava, sugarcane, plantains,

corn, oil palm, peanuts, and rice.

BRITANNICA STUDENT ENCYCLOPEDIA Congo, Democratic Republic of the 179

The country also produces coffee, cotton,

and rubber.

The next most important part of the

economy is trade, which depends on the

country’s rich natural resources. The

Democratic Republic of the Congo is a

leading producer of diamonds. It also

has deposits of petroleum, coal, copper,

cobalt, zinc, and gold.

History

Before Europeans arrived in the late

1800s, several kingdoms ruled the

region that is now the Democratic

Republic of the Congo. They included

the Kingdom of Kongo, the Luba

Empire, and the Lunda Empire.

King Leopold II of Belgium claimed the

region, which he called the Congo Free

State, in 1885. The king forced the

people to work in mines and on rubber

plantations. In 1908 the Belgian Parliament

took over the land, which it

renamed the Belgian Congo.

In June 1960 the colony gained independence

as the Republic of the Congo.

From the beginning, the president and

the prime minister fought for power. In

September 1960 the army’s chief of

staff, Joseph Mobutu, took control of

the country. In 1971 Mobutu renamed

the country the Republic of Zaire.

Mobutu ruled as a dictator who crushed

all opposition. By the 1990s, political

groups in Zaire demanded a democracy.

Rebels forced Mobutu out of the country

in 1997. Laurent Kabila took power

and changed Zaire’s name to the Democratic

Republic of the Congo. However,

rebels continued to fight the government,

and Kabila was assassinated in

2001. His son and successor, Joseph

Kabila, worked to end the civil war that

had killed millions.

..More to explore

Africa • Kinshasa • Rain Forest

The Enya people fish in the rapids of the

Congo River near Kisangani, Democratic

Republic of the Congo.

Elephants wade across a stream in the

Democratic Republic of the Congo.

Facts About

DEMOCRATIC

REPUBLIC OF THE

CONGO

Population

(2008 estimate)

66,515,000

Area

905,354 sq mi

(2,344,858 sq

km)

Capital

Kinshasa

Form of

government

Transitional

regime

Major cities

Kinshasa, Lubumbashi,

Mbuji-

Mayi, Kolwezi,

Kisangani

180 Congo, Democratic Republic of the BRITANNICA STUDENT ENCYCLOPEDIA

Congo, Republic of the

The Republic of the Congo lies on both

sides of the equator in west-central

Africa. Its capital is Brazzaville.

Geography

Congo shares borders with Gabon,

Cameroon, the Central African Republic,

the Democratic Republic of the

Congo, and Angola. It has a short coastline

on the Atlantic Ocean. The north

contains thick rain forests and swamps.

Savannas, or grasslands, cover the center.

Mountains and plateaus rise in the

southwest.

Plants and Animals

African oaks, red cedars, walnuts, and

other trees fill the rain forests. Coconut

palms and mangrove forests grow near

the coast and the swamps. Grasses and

widely spaced trees cover the savannas.

The forests contain monkeys, chimpanzees,

gorillas, elephants, and wild boars.

Antelope, jackals, hyenas, and cheetahs

roam the savannas. Rhinoceroses and

giraffes live on the plateaus.

People

About half of Congo’s people are

Bakongo, or Kongo, the ethnic group

that gave Congo its name. Other major

groups include the Sanga, the Teke, and

the Mboshi. French is the official language,

but most of the people speak

African languages. Most people are

Christians. About two thirds of the

people live in cities.

Economy

The economy of Congo depends on its

petroleum (oil) industry. Congo also

produces natural gas, wood, and gold.

Most people, however, are farmers.

Crops include cassava, sugarcane, oil

palm, bananas, and mangoes.

History

Before Portuguese explorers arrived in

1483, the Kingdom of Kongo ruled part

of what is now Congo. In 1880 France

took control of the region.

Congo gained independence in 1960. In

1992 Congo became a democracy, but

fighting soon erupted between government

forces and rebel groups. After the

civil war, voters approved a new constitution

in 2002.

..More to explore

Brazzaville

Facts About

REPUBLIC OF THE

CONGO

Population

(2008 estimate)

3,847,000

Area

132,047 sq mi

(342,000 sq km)

Capital

Brazzaville

Form of

government

Republic

Major cities

Brazzaville,

Pointe-Noire,

Dolisie, Nkayi,

Mossendjo

BRITANNICA STUDENT ENCYCLOPEDIA Congo, Republic of the 181

Congress of the

United States

#see United States Government.

Conifer

Conifers are a group of trees and shrubs

that produce cones. The cones carry

their seeds. Most conifers are

evergreens, or trees that keep their

leaves year-round. Their thin leaves are

usually called needles. There are more

than 550 types of conifer. Some of the

most well-known are cedars, cypresses,

firs, junipers, larches, pines, redwoods,

and yews. The tallest, heaviest, and

oldest living things on Earth are all

conifers.

Where Conifers Grow

Conifers grow all over the world. Forests

of conifers grow in many cool regions,

including the northern parts of Europe,

Asia, and North America. Some types of

conifer grow in tropical rain forests in

Asia. Others grow in warm parts of Australia

and Africa.

Physical Features

Conifers have woody trunks and stems.

They may be low shrubs or very tall

trees. Their leaves often look like

needles, but some types have leaves

shaped like scales, blades, or wedges. A

waxy coating keeps the leaves from losing

water. Most conifers have shallow

roots that spread out wide.

Conifers grow cones instead of flowers

or fruits. Most conifers’ cones are oval in

shape. Scales cover the outside of the

cone. Some types of conifer grow male

and female cones on the same tree. Others

have male or female cones on separate

trees. The male cones, which are

smaller than female cones, produce pollen.

Wind carries this pollen to the

female cones. Then the female cones

develop seeds under the scales. The

scales slowly open until the seeds fall

out.Wind or animals carry the seeds to

spots where new conifers can grow.

Amazing Conifers

The redwood trees in California are the

tallest conifers and the tallest trees in the

world. Some redwoods are taller than

360 feet (110 meters). The giant

sequoias, also in California, are the

heaviest conifers. They sometimes weigh

more than 4 million pounds (2 million

kilograms). The pygmy pines of New

Zealand are the smallest of all conifers.

They grow to only 2 inches (5 centimeters)

tall.

A large forest of conifers stands in the

northern European country of Finland.

182 Congress of the United States BRITANNICA STUDENT ENCYCLOPEDIA

Bristlecone pines are the oldest conifers,

as well as the oldest living things on

Earth. It is not unusual for them to live

for 3,000 to 4,000 years. They grow in

dry, mountainous regions in California

and Nevada.

Uses

People have used the wood of conifers

for thousands of years. Ancient peoples

built great sailing ships out of cedars

from the Middle East. More than 500

years ago, warriors in Europe made long

bows from the bendable wood of yews.

Today people use the wood of pines to

make houses and furniture.

People today also plant conifers in gardens,

parks, and yards. They grow them

indoors as decorative plants. People in

North America and western Europe use

pines, firs, spruces, and other conifers as

Christmas trees. In addition, conifers are

used to make such products as paper

and turpentine.

#More to explore

Cedar • Cypress • Fir • Juniper • Larch

• Pine • Redwood • Tree • Yew

Conifers grow their seeds inside cones. They usually have needle-shaped leaves. Redwoods

are the tallest conifers and the tallest trees on Earth.

BRITANNICA STUDENT ENCYCLOPEDIA Conifer 183

Connecticut

The state of Connecticut was

named for the Connecticut

River. Algonquian Indians called the

river Quinnehtukqut, meaning “land on

the long tidal river.” Connecticut is

nicknamed the Constitution State

because its early settlers wrote a set of

laws to govern themselves that later provided

ideas for the U.S. Constitution.

Those laws, known as the Fundamental

Orders of Connecticut, were created in

1638 and covered such issues as elections,

powers of officials, and taxation.

The capital of Connecticut is Hartford.

Geography

Connecticut is the southernmost New

England state. It is bordered by Massachusetts

on the north, Rhode Island on

the east, New York on the west, and the

Long Island Sound on the south.

Connecticut has highlands in the west

and east with a lowland in the middle.

The northern part of the western highlands

is called the Litchfield Hills. They

include Mount Frissell, which is the

state’s highest point at 2,380 feet (725

meters). The central lowland includes

the fertile Connecticut River valley. The

eastern highlands are low, wooded hills

with many rivers.

People

At the time of the first U.S. census, in

1790, almost all of Connecticut’s people

were English. In the 1800s Irish, French

Canadian, Italian, Polish, and other

European immigrants settled in the

state. Today more than four fifths of

Connecticut’s residents are of European

heritage. African Americans and Hispanics

each make up about 9 percent of the

population. The state’s Asian American

and Native American groups are small.

Connecticut has a large population for

its size. As a result, it is one of the country’s

most crowded states. Most of its

people live in cities or towns. Bridgeport,

on the coast, is the largest city.

Other large cities are Hartford, New

Haven, and Stamford.

Economy

Real estate, finance, and the insurance

industry are major parts of Connecticut’s

economy. Hartford is known as the

Insurance Capital of theWorld because

of the many insurance companies with

offices there. Manufacturing businesses

in Connecticut produce jet aircraft

engines, computer equipment, chemicals,

machinery, and other goods. Hart-

184 Connecticut BRITANNICA STUDENT ENCYCLOPEDIA

ford, Bridgeport, Danbury, and New

Haven are the state’s leading manufacturing

centers. New Haven is also the

site of Yale University, one of the leading

educational institutions in the United

States.

History

The first residents of the Connecticut

region were Algonquian Indians. Europeans

arrived from nearby colonies in

the 1630s. In 1633 Dutch colonists

built a fort and trading post where Hartford

now stands. English colonists from

Massachusetts established posts at what

are nowWethersfield andWindsor.

Later the English took over the Hartford

site. In 1662 the English king made

Connecticut an independent colony. In

1788 Connecticut entered the Union as

one of the original 13 states.

Connecticut was a farming region until

the early 1800s, when textile factories

were established. By 1850 more people

worked in manufacturing than in agriculture.

In the 1900s Connecticut was

called an “arsenal of democracy” because

it produced many firearms used in

WorldWars I and II and the Korean and

Vietnam wars. Manufacturing later

declined in value, but high-technology

industries boosted the economy.

..More to explore

Hartford

The museum called Mystic Seaport focuses

on the time in Connecticut’s history when

wooden sailing ships were important to the

area’s economy.

The writer Mark Twain lived in Hartford, Connecticut, for more than 15 years. The house

that he lived and worked in is now open to the public.

Facts About

CONNECTICUT

Flag

Population

(2000 census)

3,405,565—

rank, 29th state;

(2008 estimate)

3,501,252—

rank, 29th state

Capital

Hartford

Area

5,543 sq mi

(14,357 sq km)—

rank, 48th state

Statehood

January 9, 1788

Motto

Qui Transtulit

Sustinet (He Who

Transplanted Still

Sustains)

State bird

American robin

State flower

Mountain laurel

BRITANNICA STUDENT ENCYCLOPEDIA Connecticut 185

Conquistador

The Spanish word for conqueror is conquistador.

Many Spanish soldiers and

explorers traveled to the Americas after

Christopher Columbus made the first

trip in 1492. These conquistadors sailed

to the Americas to conquer the native

peoples and to spread Christianity. They

were also looking for gold and other

treasure.

Because of the conquistadors, Spanish

culture spread widely throughout South

America, Central America, and the

southern regions of North America. The

Spanish influence is strong in these areas

even today.

Many of the conquistadors’ actions were

cruel. They stole the riches that they

found in the new lands. They brutally

murdered thousands of native people.

They also brought diseases such as

smallpox that killed many more thousands.

One of the most famous conquistadors

was Hernan Cortes. He destroyed the

Aztec Empire in what is now southern

and central Mexico. Cortes arrived in

Mexico in 1519. He and his men

defeated the Aztec in 1521.

Another Spanish conquistador, Francisco

Pizarro, conquered the Inca

Empire in what is now Peru. Pizarro

came to Peru in 1531. He killed the

leader of the Inca and captured their

capital in 1533.

#More to explore

Aztec • Columbus, Christopher

• Cortes, Hernan • Inca

Conservation

Conservation is the protection of things

found in nature. It requires the sensible

use of all Earth’s natural resources:

water, soil, minerals, wildlife, and forests.

People who care about conservation

try to preserve natural resources so they

An illustration shows Spanish conquistadors supervising Native Americans, who are carrying

supplies for them.

186 Conquistador BRITANNICA STUDENT ENCYCLOPEDIA

will still be around in the future. They

also try to keep the environment clean

and healthy.

Types of Resources

Some resources are renewable, which

means they can be replaced. Living

things, such as plants and animals, are

examples of renewable resources because

they can reproduce themselves. But

renewable resources can still be

damaged or destroyed. For example,

people might catch too many of one

type of fish. If not enough fish are left

to reproduce, that type of fish might

die out. Conservation helps people

manage renewable resources so they are

kept in good supply.

Other resources are nonrenewable,

which means they cannot be replaced.

Fossil fuels, such as coal and petroleum

(oil), are examples of nonrenewable

resources. Minerals, such as iron ore,

also are nonrenewable resources. People

can conserve nonrenewable resources by

using them carefully. They can also look

for other resources that serve the same

purpose. For example, people can use

less petroleum by using other types of

fuel instead.

Conservation Challenges

Conservation can be hard because it

can require people to give up some

conveniences. For example, cars make

travel easy, but they also produce a lot

of air pollution. To have cleaner air,

people can choose to drive less and

walk more. Such changes can be hard

when people have gotten used to a

certain way of living.

Money is another reason why conservation

can be a challenge. For example, a

timber company might be able to protect

forest animals by limiting the number

of trees it cuts. But the company

might not be willing to do this because

it will make less money. Also, factories

might not want to spend the money to

clean up the messes they make.

Conservation Solutions

Everyone can contribute to

conservation in one way or another.

Workers take care of young tropical trees in

Brazil. The trees were planted to replace

trees that were cut down.

Some cities encourage people to carpool,

or share car rides. Carpooling is a good

way to conserve gasoline.

BRITANNICA STUDENT ENCYCLOPEDIA Conservation 187

People can recycle paper, plastic, glass,

and other materials. Recycling saves

resources by reusing materials that

would otherwise be thrown away.

Industries can limit the amount of

pollution they create. Governments can

make laws that help to keep the air and

water clean. Governments have also set

aside land as national parks. These

parks protect land and animals in their

natural state.

#More to explore

Environment • Fossil Fuel • National

Parks • Natural Resources • Pollution

• Recycling

Constellation

A constellation is a group of stars. The

groups are identified according to patterns

that people have seen in the stars.

For example, the stars of the constellation

Leo seem to trace the outline of a

lion. The name Leo means “lion” in the

Latin language. The constellation Draco,

whose name is Latin for “dragon,” is said

to look like a dragon. However, these are

not scientific groupings. They are simply

ways that people have imagined the

stars.

Since ancient times people have tried to

explain the night sky. Over thousands of

years different cultures have seen different

patterns in the stars. They have

named many different constellations

after familiar animals, everyday objects,

and characters and beasts from stories.

Today constellations provide a

connection between modern humans

and ancient stories. They are also

interesting to spot in the night sky.

Astronomers, or scientists who study

stars, have named 88 constellations.

They use the constellations to help

describe the location of specific stars.

Among them are the 12 well-known

constellations that lie in a band of space

called the zodiac. These are Aries,

Taurus, Gemini, Cancer, Leo, Virgo,

Libra, Scorpius, Sagittarius,

Capricornus, Aquarius, and Pisces.

A person looking at the sky from the

same point every night will see different

constellations at different times of year.

This happens because Earth moves

around the sun, while the stars do not.

Earth completes one trip around the sun

The constellation Orion is associated

with a character in Greek

mythology who was a hunter. An

illustration shows how the stars

of the constellation might be

seen as the image of a hunter.

The sky above

the Southern

Hemisphere

(half of the

world) and the

sky above the

Northern

Hemisphere

have different

sets of constellations.

188 Constellation BRITANNICA STUDENT ENCYCLOPEDIA

each year, so different stars are visible

from Earth in the course of a year.

#More to explore

Astronomy • Star

Constitution

A constitution is a set of rules that

guides how a country, state, or other

political organization works. The constitution

may tell what the branches of the

government are, what powers they have,

and how they work. It may also state the

rights of citizens. The government’s

other laws are not allowed to disagree

with its constitution. The constitution

may be amended, or changed, but this is

generally more difficult to do than passing

an ordinary law.

Development of Constitutions

The first people to think about constitutions

were the ancient Greeks. They

established a form of democracy, in

which some of the people had a say in

how the government was run. For hundreds

of years after this, however, most

people were ruled by kings or queens.

The people had no rights, and they had

no say in how they were governed. Eventually

that began to change. In 1215 the

landowners in England were upset with

their cruel and greedy ruler, King John.

They banded together and forced the

king to sign a document that guaranteed

them certain rights. The document was

called the Magna Carta. The Magna

Carta served as a model for many future

constitutions.

In the 1600s and 1700s thinkers like

John Locke in England and Jean-Jacques

Rousseau in France wrote about an idea

called the social contract. This idea

states that people give up their freedom

to do anything they want in return for

the protection of a stable government.

These thinkers influenced the writing of

the U.S. Constitution in 1787.

Modern Constitutions

The U.S. Constitution took effect in

1789. It is now the oldest written constitution.

It has set a pattern for many

other countries. Today almost all countries

have written constitutions. Many

have had several in their history.

One country without a written constitution

is Saudi Arabia. Its uses the Koran

and other Islamic teachings as its highest

law. The most famous example of a

country without a written constitution

The original signed copy of the U.S. Constitution

is one of the treasures of the National

Archives in Washington, D.C.

BRITANNICA STUDENT ENCYCLOPEDIA Constitution 189

is the United Kingdom. The British

constitution is a group of laws that have

built up throughout history. Its elements

include the Magna Carta, the English

Bill of Rights of 1689, laws passed by

Parliament, court decisions, and other

sources.

Not all constitutions come from the

people of the country. For example, the

United States set up the Japanese constitution

of 1947 after it defeated Japan in

WorldWar II. And even the finest constitution

does not guarantee that the

government will follow it. Dictators, or

rulers who take unlimited power, often

ignore their country’s constitution.

#More to explore

Amendment • Government • Magna

Carta • United States Constitution

Continent

On a globe, continents are the easiest

things to spot. A continent is a large

solid area of land. Earth has seven continents.

In order from largest to smallest,

they are Asia, Africa, North America,

South America, Antarctica, Europe, and

Australia. Sometimes people think of

Europe and Asia as a single continent

called Eurasia.

The continents have different kinds of

weather, landscapes, and populations.

For instance, Antarctica is icy and has

very little plant and animal life. Africa,

though, tends to be very warm and has a

great variety of plants and animals.

Most of the continents are also divided

into political units called countries. Parts

of Antarctica are claimed by several

countries, but there are no permanent

settlements on the continent. Australia is

the only continent that is occupied by a

single country.

In 1912 a German scientist named

AlfredWegener came up with the idea

that the continents were once all joined

together. He called this large body of

land Pangaea. He suggested that more

190 Continent BRITANNICA STUDENT ENCYCLOPEDIA

than 200 million years ago Pangaea split

apart to form the continents. The continents

then drifted apart to their current

locations.

Scientists since then have found evidence

that this idea is correct. They now

believe that the continents sit on a number

of large plates. The plates float on a

layer of melted rock. As the plates slide

over the melted rock, the continents also

move. This idea is called plate tectonics.

#More to explore

Africa • Antarctica • Asia • Australia

• Europe • Map and Globe • North

America • Plate Tectonics • South

America

Continental

Congress

The Continental Congress was the first

government of the United States. When

the congress adopted the Declaration of

Independence on July 4, 1776, it

brought the United States into existence.

It then served as the country’s government

until the U.S. Constitution went

into effect in 1789.

First Continental Congress

In the early 1770s citizens of the 13

British colonies in North America were

starting to rebel against Great Britain. A

network of patriots, known as the Committees

of Correspondence, called

together the First Continental Congress

to plan future action.

The First Continental Congress met in

secret in Philadelphia, Pennsylvania, on

September 5, 1774. All colonies except

Georgia sent delegates, or representatives.

GeorgeWashington, Patrick

Henry, John Adams, and Samuel Adams

were among them. Each colony had one

vote.

The delegates decided not to call for

independence from Britain. Instead

they demanded such rights as life,

liberty, property, public assembly, and

trial by jury. They protested having to

pay British taxes without being

represented in Parliament (the part of

the British government that made laws).

The congress also called for the colonies

to boycott, or refuse to buy, British

goods.

Second Continental Congress

The American Revolution had already

begun when the Second Continental

Congress opened in Philadelphia on

May 10, 1775. Delegates from all 13

The First Continental Congress met in Philadelphia,

Pennsylvania, on September 5,

1774.

BRITANNICA STUDENT ENCYCLOPEDIA Continental Congress 191

colonies attended the congress. New

delegates included Benjamin Franklin

and Thomas Jefferson. Among those

serving as president were John Hancock

and John Jay.

The congress took control of the colonies’

new Continental Army. It put

Washington in command of the army.

The congress also issued and borrowed

money and set up a postal service and a

navy.

At first the congress still said that the

colonists were fighting for their rights as

British citizens. On July 2, 1776, however,

the congress stated that the colonies

should be independent states. The

congress declared independence from

Britain two days later.

The congress prepared the Articles of

Confederation, which served as the first

constitution of the new United States.

The articles went into effect in 1781.

They gave Congress official powers.

After that, the Continental Congress

became known as the Confederation

Congress.

The Confederation Congress had little

real control over the states. In 1789 the

new U.S. Constitution set up the U.S.

Congress. The U.S. Congress replaced

the Confederation Congress.

#More to explore

American Revolution • Articles of

Confederation • Declaration of

Independence • United States • United

States Constitution

Continental

Drift

#see Plate Tectonics.

Cook, James

A British explorer and navigator, Captain

James Cook led three expeditions to

the Pacific Ocean. His voyages took him

south to the Antarctic Circle and north

to the Bering Strait.

Early Life

James Cook was born on October 27,

1728, in Marton, Yorkshire, England.

At age 18 he became a sailor on the

North Sea. While ashore he studied

mathematics.

In 1755 Cook joined the British Royal

Navy. He was promoted quickly and

The Second

Continental

Congress did

not have a

permanent

home. Its final

seat was New

York City.

James Cook

192 Continental Drift BRITANNICA STUDENT ENCYCLOPEDIA

Coolidge, Calvin

The 30th president of the United

States, Calvin Coolidge took office after

the death of President Warren G.

Harding in 1923. A popular politician,

he served during a period of economic

growth.

Early Life

John Calvin Coolidge was born on July

4, 1872, in Plymouth, Vermont. He

was the only son of a storekeeper, John

Calvin Coolidge, Sr., and Victoria

Moor Coolidge. Coolidge graduated

from Amherst College in Massachusetts

in 1895. Two years later he became a

lawyer. In 1905 he married Grace Anna

Goodhue, a teacher. They had two

sons.

Political Career

A Republican, Coolidge entered politics

as a city councilman in Northampton,

Massachusetts, in 1898. In 1909 he was

elected mayor of Northampton. He

served as a Massachusetts state senator

from 1911 to 1915 and as lieutenant

governor from 1915 to 1918.

Coolidge was elected governor of Massachusetts

in 1918. During a 1919 strike

(refusal to work) by the Boston police,

riots broke out. Coolidge sent the state

guard to restore order. He became

July 4, January 5,

1872 1918 1923 1924 1928 1929 1933

Coolidge is

born in

Plymouth,

Vermont.

Coolidge is

elected

governor of

Massachusetts.

Coolidge

becomes

president after

Harding dies.

Coolidge is

elected to a full

term.

The Kellogg-

Briand Pact

is signed.

Coolidge

retires from

office.

Coolidge

dies in

Northampton,

Massachusetts.

T I M E L I N E

Calvin Coolidge was the 30th president of

the United States.

194 Coolidge, Calvin BRITANNICA STUDENT ENCYCLOPEDIA

famous for saying that police officers did

not have the right to strike.

In 1920 Coolidge became Harding’s

vice presidential running mate. They

won the election with 60 percent of the

popular vote.

Presidency

When Harding died suddenly in 1923,

Coolidge became president. The public

soon learned that Harding had allowed

government officials to make illegal

business deals. Coolidge quickly punished

people involved in the deals. He

restored people’s faith in the presidency.

In 1924 Coolidge easily won the presidential

election.

Coolidge encouraged the expansion of

industry. He also led Congress to reduce

taxes. The economy grew significantly

during his term.

Coolidge generally avoided international

affairs. One exception was the Kellogg-

Briand Pact of 1928, which Coolidge’s

secretary of state helped to create. In the

pact, 62 nations agreed to end war as a

way of solving conflicts.

Retirement

Despite his popularity, Coolidge decided

not to run for reelection. In 1929 he

retired to Northampton, where he wrote

his autobiography and magazine and

newspaper articles. He died of a heart

attack on January 5, 1933.

..More to explore

Harding,Warren G.

Copenhagen

Population

(2008

estimate), urban

area,

1,153,615

Copenhagen is the capital of Denmark,

a country of northern Europe. The city

is a leading center of culture and

education in Europe. It is also the

largest city in Denmark. Copenhagen is

located on the islands of Zealand and

Amager.

In Copenhagen’s harbor is a statue that

some people say is the symbol of the

city. The statue shows the Little Mermaid,

a character from a fairy tale by

Hans Christian Andersen. Andersen

lived in Copenhagen most of his life.

Copenhagen is the center of business in

Denmark. Many people in the city work

for the government. Others work in

banking, education, communications,

and computer services. Factories in

Copenhagen process foods and make

medical equipment and medicines.

Shipping and trade through the port

also bring money to the city.

Copenhagen began as a small fishing

village that grew up around the harbor.

The village was settled by the 900s. In

1167 a fortress was built to protect the

village. Copenhagen became the capital

Copenhagen

has a worldfamous

amusement

park called

Tivoli.

BRITANNICA STUDENT ENCYCLOPEDIA Copenhagen 195

of Denmark in 1445. In the late 1500s

the city grew as a center of trade.

Two fires in the 1700s destroyed many

buildings in Copenhagen. The British

attacked the city in the early 1800s as

part of a larger war. However, Copenhagen

continued to grow.

#More to explore

Andersen, Hans Christian • Denmark

Copernicus,

Nicolaus

The Polish astronomer Nicolaus Copernicus

was the first person to state that

Earth and the other planets travel

around the sun. This was an important

change in thinking. For hundreds of

years before that, most scholars believed

that the sun, stars, and planets revolved

around Earth. But they were mistaken.

Copernicus was born in Torun, Poland,

on February 19, 1473. He studied in

Poland and later in Italy. Copernicus

learned several subjects, including

astronomy, mathematics, medicine, and

church law. Following his studies, he

became an officer in the Roman Catholic

church. In his spare time he observed

the skies.

Copernicus developed many ideas about

the solar system, or the sun and the

objects that revolve around it. He correctly

stated that Earth travels around

the sun and also spins about its center.

Copernicus published his ideas in a

book in 1543. He died that same year,

on May 24 in what is now Frombork,

Poland. His book did not immediately

change the way people viewed the solar

A statue of the Little Mermaid sits

in Copenhagen’s harbor. The

statue is based on a story by

Hans Christian Andersen, an

author who lived in Copenhagen.

Nicolaus Copernicus

196 Copernicus, Nicolaus BRITANNICA STUDENT ENCYCLOPEDIA

system, but later thinkers realized that

his ideas were correct.

#More to explore

Astronomy • Planets • Solar System

Coral

Corals are sea animals that stay in one

place throughout their adult lives. Some

types produce a skeleton, also called

coral, that remains in place after they

die. Corals can be very colorful underwater,

but most types fade when they die

or are removed from the water. Corals

belong to the same animal group as sea

anemones.

Where Corals Live

Corals live in all the oceans of the world.

Some types live alone. Many types live

together in groups called colonies. Several

different types of corals together can

form enormous colonies. These colonies

are called coral reefs. The largest coral

reef in the world is the Great Barrier

Reef off the coast of Australia.

Physical Features

The many types of coral include stony,

soft, black, thorny, horny, and blue corals.

As they grow, corals form different

patterns and shapes. They may look like

feathers, fingers, branches, or even a

brain.

The body of a coral is called a polyp.

The polyp is a hollow structure that

attaches to a surface. Polyps of large

corals may grow to about 10 inches (25

centimeters) across. Other corals have

polyps as small as 0.04 inch (1 millimeter)

across. At the top of the polyp is a

mouth surrounded by tentacles. The

tentacles bring small sea animals to the

mouth. The tentacles also have stingers

that paralyze, or freeze, corals’ prey.

Corals have a skeleton that may be outside

or inside the body. Stony corals

have a hard, outside skeleton made of a

mineral called calcium carbonate. As

these corals die, new corals build up a

colony on top of the dead corals’ skeletons.

Life Cycle

To reproduce, corals produce eggs that

develop into tiny, swimming creatures

called planulae. Planulae eventually

settle on a surface and develop into polyps.

Corals also reproduce by budding.

A bud is a new polyp that develops on

the body of an old polyp. Some types of

coral may live for hundreds of years.

Coral reefs

are sometimes

called the rain

forests of the

sea. Like rain

forests, they

are home to

many different

kinds of living

things.

Corals are small colorful animals that live in

oceans all over the world.

BRITANNICA STUDENT ENCYCLOPEDIA Coral 197

Corals and Humans

People have long used coral skeletons to

make jewelry. But this and other human

activities have put many corals at risk.

Rising ocean temperatures, oil spills, and

chemical pollution harm corals. Boats

that float over reefs may also damage

corals.

#More to explore

Great Barrier Reef • Sea Anemone

Coral Snake

Coral snakes are very poisonous snakes

with bright color patterns. Red, black,

and yellow or white rings circle a coral

snake’s body. These markings warn

other animals that the snake is dangerous.

Coral snakes belong to the cobra family.

There are about 90 species, or kinds, of

coral snake. They live in the Americas,

from the southern United States to

Argentina. Most are found in the tropics.

Similar snakes live in Africa and

Asia. Many harmless snakes have ring

patterns like those of coral snakes. This

makes other animals think they are dangerous.

Coral snakes have slender bodies with

smooth scales. Most measure less than 3

feet (0.9 meter) long. Some South

American varieties can grow longer than

4 feet (1.2 meters).

Coral snakes have short, hollow fangs

that deliver a powerful venom, or poison.

The venom attacks the nervous

system and can be deadly to people.

Most coral snakes are quick to bite when

disturbed.

Coral snakes stay hidden in underground

homes called burrows during the

day. At night they come out to eat other

snakes and small lizards.

#More to explore

Cobra • Nervous System • Snake

Cork

Every year billions of bottles of wine,

cooking oil, and other liquids are sealed

with corks. Corks are made from the

bark of a type of oak tree called the cork

oak. The tree grows near the Mediterranean

Sea.

The cork oak usually grows to be about

60 feet (18 meters) tall. Its widespreading

branches give it a shape like

an umbrella. Its narrow leaves are dark

green and glossy.

The bark of the cork oak grows in two

layers. The thick outer layer is the cork.

Coral snakes have brightly colored markings

to show other animals that they are

poisonous.

198 Coral Snake BRITANNICA STUDENT ENCYCLOPEDIA

Tiny bubbles of air trapped between the

cells of the cork make it spongy. After

cork is removed from the tree, a new

layer forms over a period of years.

How Cork Is Harvested

In the summer, workers cut slabs of the

outer layer of bark from the tree. The

slabs are stacked to dry and then boiled

in water to remove any tree sap. Boiling

also softens the cork, which makes it

easy to press flat. The flattened cork can

be cut into many shapes. It can also be

ground into very small pieces and then

mixed with glue and shaped to make

various products.

Uses

Cork is useful as a stopper for bottles

because liquids cannot pass through it.

Cork is also a natural insulating material.

It can be used to keep a house warm

or to absorb sound. Because cork floats,

it is used to make life preservers and

buoys. Cork is also soft and springy,

making it good for shoe soles. It is also

used to make bulletin boards.

Corn

Corn, or maize, is one of the most

widely grown food plants in the world.

People eat the plant’s seeds, which are

called kernels or grains. Corn belongs to

the grass family. Its scientific name is

Zea mays.

Corn first grew in the Americas. Early

European explorers took corn to Europe.

Today farmers grow corn in many areas

of the world. The United States, China,

Brazil, Mexico, and Argentina are major

producers of corn.

The corn plant is tall. It has a stout stem

with a tassel at the top. Large, narrow

leaves grow out from the stem. Spikes

grow from under the bases of the leaves.

These spikes are a form of flower. They

develop into ears, which contain the

seeds that people eat. Leaves called

shucks or husks surround each ear.

A worker cuts away the bark from a cork

oak in Portugal. The bark will be used to

make cork.

Rows of golden corn line a Nebraska field.

BRITANNICA STUDENT ENCYCLOPEDIA Corn 199

There are many varieties of corn plants.

Native Americans grew corn with yellow,

red, blue, pink, or black kernels.

Today most corn has yellow kernels.

Corn kernels may be soft, hard, starchy,

or sweet. The hardest kernels are called

popcorn. They explode when heated.

People in Latin America grind up corn

kernels to make masa. Masa is a kind of

dough used in tortillas, tamales, and

other foods. In the United States sweet

corn is a popular food. People often eat

boiled or roasted corn on the cob. They

also use the kernels in corn bread and

other dishes. Farmers feed other kinds

of corn to their farm animals. The parts

of the plant that are not eaten may be

made into paper, fuel, and other

products.

#More to explore

Grain • Grass • Seed

Coronado,

Francisco

In search of gold, Francisco Coronado

led the first major European expedition

north from Mexico. His travels in the

1540s established Spain’s later claims to

what is now the southwestern United

States.

Francisco Vazquez de Coronado was

born in Salamanca, Spain, in about

1510. He arrived in the NewWorld in

1535 with Antonio de Mendoza, the

new ruler of New Spain (Mexico). In

1538, after putting down a slave revolt,

Coronado became governor of a Mexican

province.

At about that time the Spanish heard

tales of towns filled with riches. Mendoza

put Coronado in charge of a large

expedition to find the towns and to

bring back their treasures.

Coronado set out in 1540. In what is

now New Mexico he indeed found cities,

but they were made of adobe (sunbaked

clay), not gold. They were the

pueblos (villages) of the Zuni Native

Americans. However, some of his men

became the first Europeans to see the

Grand Canyon.

In spring 1541 Coronado went on to

what is now Kansas because a Native

American woman had told him of

another fabulously wealthy land called

Quivira. It again turned out to be only

an Indian village, but the Spaniards

became the first Europeans to see the

Great Plains and the large bison (buffalo)

herds that roamed there.

A substance

called highfructose

corn

syrup is used

to sweeten soft

drinks. It is

made from

corn.

200 Coronado, Francisco BRITANNICA STUDENT ENCYCLOPEDIA

In 1544 Coronado was charged with

corruption and cruelty to the Native

Americans. He was later removed from

his governorship. He died on September

22, 1554.

#More to explore

Zuni

Cortes, Hernan

The Spanish soldier Hernan Cortes conquered

the great Aztec Empire in 1521.

The conquest began 300 years of Spanish

rule over Mexico.

Hernan Cortes (also called Hernando

Cortez) was born in 1485 in Medellin,

Spain. At age 19 he sailed for the island

of Hispaniola in theWest Indies. There

he farmed and did legal work. In 1511

he helped Diego Velasquez conquer

Cuba. Cortes became mayor of Santiago,

the capital.

In 1518 Velasquez asked Cortes to start

a colony in Mexico. While exploring the

coast Cortes learned about the Aztec

Empire. He landed at what is now Veracruz

in April 1519. He burned his ships

so his men could not turn back.

After defeating the Tlaxcaltec people in

battle, Cortes made them his allies. The

Tlaxcaltec and other tribes resented

Aztec demands for sacrifices and treasure.

On November 8, 1519, Cortes

marched into the Aztec capital of

Tenochtitlan (now Mexico City). The

Aztec emperor Montezuma II welcomed

Cortes because he thought he was a god

of Aztec legend. Cortes quickly seized

power.

Meanwhile, the jealous Velasquez sent a

Spanish force against Cortes. Cortes

defeated them, but while he was away

the Aztec regrouped. They drove his

forces back. Cortes then rejoined the

Tlaxcaltec. He captured Tenochtitlan on

A painting shows Hernan Cortes leading a group of Tlaxcaltecs to the Aztec capital of

Tenochtitlan.

BRITANNICA STUDENT ENCYCLOPEDIA Cortes, Hernan 201

August 13, 1521, ending the Aztec

Empire.

The king of Spain made Cortes a nobleman.

Cortes spent the 1530s in Mexico

and explored Baja California in 1534–

35. In 1540 he went back to Spain. He

died there on December 2, 1547.

#More to explore

Aztec • Mexico

Cosmetics

Cosmetics are products that people put

on their bodies to make themselves feel

more beautiful. There are many types of

cosmetics, including face makeup, nail

polish, lotions, perfumes, and shampoos.

Cosmetics are very popular today,

and they were also used in ancient times.

Types of Cosmetics

Many women use cosmetics for the face.

Makeup, or foundation, gives the face

color and highlights the features. Powder

helps make the face look less shiny.

Blush makes cheeks look rosy. Lipstick

gives the lips color and shine. Eye

shadow and eyeliner can make the eyes

look bigger or more dramatic. Mascara

makes the eyelashes thicker and darker.

Many types of oils and lotions can

soften the skin on the hands and body.

Shampoos clean the hair, and

conditioners help keep the hair soft and

healthy. People use hair creams, gels,

and sprays to style the hair. Hair tints

and dyes come in many different colors.

Some are natural vegetable dyes such as

henna, which has a reddish tone. Other

hair color treatments use chemical

bleaches.

History

Ancient Egyptians were the first people

known to use cosmetics. Egyptian men

and women used perfumed oils to keep

their skin from drying out. They also

used natural coloring on their eyelids

and eyelashes. The Romans later introduced

more types of cosmetics.

For much of history rich and powerful

people were the main users of cosmetics.

In the 20th century cosmetics became

cheaper and more widely used. Today

millions of people throughout the world

use cosmetics every day.

#More to explore

Egypt, Ancient

Many people all over the world use cosmetics

to make themselves feel more beautiful.

202 Cosmetics BRITANNICA STUDENT ENCYCLOPEDIA

Costa Rica

The Republic of Costa Rica is known

for having the most stable democratic

government in Central America. Its

name means “rich coast.” The capital

and largest city is San Jose.

Geography

Costa Rica is surrounded by Nicaragua,

the Pacific Ocean, Panama, and the

Caribbean Sea.Mountains—some with

active volcanoes—run through the land.

Earthquakes are also a danger. The

coastal plains are hot year-round, while

the mountains have milder temperatures.

Plants and Animals

Forests of broad-leaved, evergreen trees

cover much of Costa Rica. The country

has both North and South American

types of animals. South American

animals include monkeys, anteaters, and

sloths. North American ones include

deer, wildcats, and coyotes. Tropical

birds, snakes, and iguanas are also

common.

People

Most Costa Ricans are white. Many

others are mestizos (people with mixed

European and Native American roots).

There are also small groups of Africans,

Asians, and Native Americans. Spanish

is the official language. Most people are

Roman Catholics.

Economy

Manufacturing, trade, tourism, and

other services are the main economic

activities. Manufacturers make mainly

food products and beverages. Exports

include electronic parts and bananas.

History

Before Christopher Columbus arrived

in 1502, Native Americans lived in

what is now Costa Rica. The area was a

colony of Spain until 1821, when it

joined the Mexican Empire. In 1823

Costa Rica and four other countries

declared their independence from

Mexico as the United Provinces of

Central America. Costa Rica left that

union in 1838.

In 1890 Costa Rica held the first free

and honest election in Central America.

Despite brief revolutions in 1917 and

1948, the country developed peacefully.

In the late 20th century Costa Rica

helped to settle political fighting in

neighboring countries.

#More to explore

Central America • San Jose

Facts About

COSTA RICA

Population

(2008 estimate)

4,389,000

Area

19,730 sq mi

(51,100 sq km)

Capital

San Jose

Form of

government

Republic

Major cities

San Jose, Limon,

Alajuela, San

Isidro de El General,

Cartago,

Liberia

BRITANNICA STUDENT ENCYCLOPEDIA Costa Rica 203

Cote d’Ivoire

The Republic of Cote d’Ivoire lies on

the west coast of Africa. Its name, meaning

“Ivory Coast,” came from its trade in

elephant tusks, or ivory. Yamoussoukro

is the official capital, but most government

offices are in Abidjan.

Cote d’Ivoire shares borders with

Liberia, Guinea, Mali, Burkina Faso,

and Ghana. The Atlantic Ocean lies to

the south. The land rises from the coast

to high savanna, or grassland, in the

north. Mountains run through the west.

The climate is generally hot and humid.

The tropical rain forest in the south

contains teak trees. Its wildlife includes

giant forest hogs and bongos (a type of

antelope). Antelope, lions, and elephants

live in the northern savanna.

Major ethnic groups include the Akan

and theMande. French is the official

language.Most people areMuslim or

Christian, but many follow traditional

African religions or no religion.

Cote d’Ivoire’s economy depends on

agriculture. Farmers grow yams, cassava,

and other crops for food. They grow

cocoa and coffee for export. The country

also produces petroleum (oil), natural

gas, wood, gold, and diamonds.

Important kingdoms existed in the

region for centuries before Europeans

arrived in the 1400s. The Europeans

built a trade in ivory and slaves. In 1893

France made the region a colony. Cote

d’Ivoire gained independence in 1960.

Years of unrest led to a civil war in the

early 21st century.

..More to explore

Abidjan • Yamoussoukro

Growing and selling fruits and

vegetables is an important part

of Cote d’Ivoire’s economy.

Facts About

COTE D’IVOIRE

Population

(2008 estimate)

19,624,000

Area

123,863 sq mi

(320,803 sq km)

Capital

Yamoussoukro

Form of

government

Republic

Major cities

Abidjan, Bouake,

Daloa,

Yamoussoukro

204 Cote d’Ivoire BRITANNICA STUDENT ENCYCLOPEDIA

Cotonou

Population

(2004 estimate)

818,100

Cotonou is the largest and most important

city in theWest African country of

Benin. Although Porto-Novo is Benin’s

capital, the president and many government

officials work in Cotonou.

Cotonou lies at the southern end of

Benin on the Gulf of Guinea. It is an

important port and the business center

of Benin. The main products made in

Cotonou are cloth goods, beverages, and

palm oil.

Cotonou is also a lively city filled with

street sellers and markets. The Artisanal

Center offers arts and crafts made by

local artists. The Marche Dantokpa is a

large, open-air market with many goods

for sale. Cotonou’s beaches attract many

visitors. The National University of

Benin is located in Cotonou as well.

The land around Cotonou was once

known as Dahomey. In the 1800s the

French slowly took control of Cotonou

from the king of Dahomey. The French

conquered all of Dahomey by 1894.

Dahomey gained independence in 1960.

The country finished building a modern

port at Cotonou in 1965.

#More to explore

Benin • Porto-Novo

Cotton

Cotton is a fiber, or hairlike material,

that people use to make cloth and other

goods. Cotton grows on shrublike

plants. Cotton plants belong to the mallow

family, which also includes hollyhock

and okra.

Where Cotton Grows

Cotton plants grow in warm areas in

many parts of the world. Some of the

top cotton-growing countries are China,

the United States, Pakistan, India, and

Uzbekistan.

Physical Features

In the wild, cotton plants may reach a

height of 20 feet (6 meters). As a crop,

cotton plants grow only 3 to 6 feet (1 to

2 meters) high.

Cotton plants produce white flowers

that turn red and then fall away. The