Britannica Student Encyclopedia - 2010

move around.

A mental disability is a problem with the

brain, or mind. Mental disabilities

The smallest dinosaurs were less than 3 feet (0.9 meter) long.

BRITANNICA STUDENT ENCYCLOPEDIA Disability 53

include developmental disabilities (mental

retardation), mental illness, and

learning disabilities, such as dyslexia. A

person with a mental disability may have

trouble learning or getting along with

other people.

With medical treatment or other help,

people with disabilities can do many of

the things that nondisabled people can

do. A person with a missing leg can

learn to walk with an artificial leg. Many

kinds of mental illness can be treated

with medication or other therapies.

Organizations in a community can help

people with developmental disabilities

go to school, work, or live on their own.

#More to explore

Special Olympics

Discrimination

Discrimination is unfair treatment of one

particular person or group of people.

Usually the different treatment is because

of the person’s sex, religion, race, age,

nationality, or other personal traits.

Discrimination prevents people from

doing things that other people can do

freely. It can happen in many ways and

in many areas of life. It can happen at

work, in public, and at school. For

example, if a student is not allowed to

go to a school because of his or her race,

the school is discriminating against that

student.

Sometimes even governments have discriminated

against whole groups of citizens.

A government may pass laws that

make it harder for certain groups of

people to vote, to go to school, to travel

freely, or to do other things. For

example, South Africa had a system of

discrimination against the non-white

people of the country for many years.

The system was called apartheid.

Discrimination happens throughout the

world. It is worse in some countries than

in others. In the United States many

In South Africa, during the period called

apartheid, blacks were not allowed to use

the same beaches as whites. Such a rule is a

form of discrimination.

Some children with a physical disability

may use a wheelchair to get around.

54 Discrimination BRITANNICA STUDENT ENCYCLOPEDIA

people have worked to end discrimination.

One of the most important laws

passed to end discrimination was the

Civil Rights Act of 1964. This law protects

people from discrimination based

on race and skin color, the country a

person comes from, sex, and religion.

The U.S. government has also tried to

stop other forms of discrimination.

These include treating people differently

because of their age or because they have

a disability.

#More to explore

Apartheid • Civil Rights Movement

Disease, Animal

Animals other than humans can suffer

from diseases, or illnesses, just as

humans do. People worry mainly about

the diseases that affect animals used for

food, the diseases that affect pets, and

the diseases that can be spread from

animals to people.

Like human diseases, animal diseases

may be divided into two groups: infectious

diseases and noninfectious diseases.

Animal doctors, called veterinarians, can

treat many of these diseases.

Infectious Diseases

Infectious diseases can spread from one

animal to another. These diseases are

caused by germs called viruses and tiny

living things—bacteria, protozoans,

fungi, and worms.

One of the most feared animal diseases

is rabies. Rabies attacks the brain. A

virus found in the saliva of animals with

rabies causes the disease. Rabies most

often spreads through bites. People can

catch rabies, too. However, a vaccine can

protect people as well as animals from

rabies.

Another virus causes Newcastle disease,

which affects chickens, turkeys, and pet

birds. The symptoms are like those of

influenza, or flu. People can catch this

disease from sick birds.

Tuberculosis, a disease caused by bacteria,

affects cattle. The disease harms the

lungs. Tuberculosis can be spread to

people through cow’s milk. Because of

this, milk is often heated in a process

called pasteurization. This kills the bacteria

before they can infect a person.

Mad cow disease is caused by a particle,

or tiny piece, of protein called a prion.

Mad cow disease affects the brains of

cattle. Farmers kill cattle that are sick

with mad cow disease to keep the disease

from spreading. People can catch mad

cow disease by eating meat from sick

cattle.

A veterinarian looks at a bulldog. Veterinarians

can treat many animal diseases.

BRITANNICA STUDENT ENCYCLOPEDIA Disease, Animal 55

Heartworm is a serious disease of cats

and dogs. A worm that infects the heart

causes the disease. Medicines can prevent

and treat heartworm.

Noninfectious Diseases

Noninfectious diseases cannot be spread

from one animal to another. Many of

these diseases are similar to noninfectious

diseases in humans. Cancer affects

many older dogs, cats, and other animals.

Pets and many wild animals can

suffer from arteriosclerosis. This is a

disease in which the blood vessels

become blocked. Many animals can also

develop cloudy growths, called cataracts,

over their eyes.

#More to explore

Animal • Disease, Human • Vaccine

Disease, Human

Diseases, also called illnesses or sicknesses,

are conditions that make people

unhealthy. Human diseases fall into two

major groups: infectious diseases and

noninfectious diseases.

Infectious Diseases

Infectious diseases are contagious, or

catching. People may catch these diseases

in a number of ways. Direct contact

between humans spreads some

infectious diseases. Animals, such as

mosquitoes, spread others. Still others

spread through air, water, or food.

Tiny living things called pathogens, or

germs, cause infectious diseases. Once a

pathogen has entered the body, the person

is said to be infected. Pathogens

include viruses, bacteria, fungi, and protozoans.

Some diseases caused by viruses are the

common cold, influenza (the flu),

chicken pox, measles, and AIDS. Diseases

caused by bacteria include strep

throat, tuberculosis, and Lyme disease.

Fungi cause some skin diseases—for

example, athlete’s foot and ringworm.

Different protozoans cause malaria and

sleeping sickness.

Doctors can often cure diseases caused

by bacteria with drugs called antibiotics.

Various medicines can treat diseases

To learn more about human diseases and disorders, turn to these articles:

AIDS

Alzheimer’s Disease

Arthritis

Asthma

Cancer

Cerebral Palsy

Chicken Pox

Cholera

Cold, Common

Diabetes

Down Syndrome

Epilepsy

Food Poisoning

Hepatitis

Influenza

Lyme Disease

Malaria

Measles

Meningitis

Mental Illness

Mononucleosis

Mumps

Parkinson’s Disease

Plague

Pneumonia

Polio

Reye’s Syndrome

Rubella

Scarlet Fever

Smallpox

Strep Throat

Tonsillitis

Tuberculosis

West Nile Virus

Yellow Fever

56 Disease, Human BRITANNICA STUDENT ENCYCLOPEDIA

caused by viruses, fungi, and protozoans.

Doctors also use vaccines to prevent

people from catching many infectious

diseases, especially those caused by bacteria

and viruses.

Noninfectious Diseases

Many human diseases do not result from

pathogens. These diseases are called

noninfectious. They are not contagious.

Some noninfectious diseases are inherited,

or passed down through families.

They happen when there is a problem

with one or more genes. (Genes are tiny

units of information inside a person’s

cells.) Sickle cell anemia is a common

inherited disease. It affects the shape of

blood cells.

A person’s lifestyle can lead to certain

noninfectious diseases. People who eat

poorly and do not exercise are in danger

of getting heart disease or diabetes.

People who smoke cigarettes are more

likely to get lung cancer than nonsmokers.

Environmental dangers or pollution can

also cause noninfectious diseases. People

who live close to polluting factories or

toxic waste dumps may get cancer or

other diseases.

Doctors do not know the exact causes of

many noninfectious diseases. Alzheimer’s

disease and multiple sclerosis are

two diseases whose causes are unknown.

Drugs, surgery, and other treatments can

help to control some noninfectious diseases.

But many of these diseases cannot

be cured. Scientists today are researching

ways to cure inherited and other noninfectious

diseases.

#More to explore

Bacteria • Genetics • Medicine • Virus

Disney,Walt

Walt Disney was a pioneer in the field of

animated, or cartoon, films. He is best

known for creating such characters as

Mickey Mouse and Donald Duck.

Walter Elias Disney was born on

December 5, 1901, in Chicago, Illinois.

At an early ageWalt had a gift for

drawing and painting. While attending

high school he took art classes to develop

these skills. Disney left school to serve as

an ambulance driver duringWorldWar I.

Walt Disney stands by a picture of Mickey

Mouse. Mickey Mouse starred in more than

100 short cartoons.

BRITANNICA STUDENT ENCYCLOPEDIA Disney, Walt 57

In 1923 Disney moved to Hollywood,

California. There he began creating the

characters that would make him famous.

In 1928 he released the short cartoon

film SteamboatWillie. It starred a cheerful

mouse named Mickey. The next year

Disney formedWalt Disney Productions

to create more animated films.

Other popular cartoon characters followed.

In the 1930s audiences were

introduced to Minnie Mouse, Donald

Duck, and Goofy. Disney’s first fulllength

animated film, Snow White and

the Seven Dwarfs, was released in 1937.

In the 1940s Disney’s company began

making movies with live actors. Mary

Poppins, from 1964, was the most

successful of these. Disney also

continued making animated features,

including such classics as Pinocchio

(1940), Cinderella (1950), and Peter

Pan (1953).

In 1955 Disney’s company opened Disneyland,

a large theme park in Anaheim,

California. Walt DisneyWorld, a second

and larger amusement park, opened in

Orlando, Florida, in 1971. Disney died

on December 15, 1966.

#More to explore

Animation • Cartoon • Movie

Diwali

The Hindu religious holiday called

Diwali (or Divali) celebrates the new

year. Diwali is a major holiday in India,

but it is celebrated by people living outside

of India as well. The name Diwali

comes from a Sanskrit word that means

“row of lights.” The holiday is often

called the Festival of Lights. During

Diwali small lamps filled with oil light

up houses and temples. The lights are

meant to welcome the goddess of

wealth. The festivities last for five days.

The fourth day marks the start of the

new year on the Hindu calendar. On the

calendar used by most of the world,

Diwali falls in late October or early

November.

Diwali is one of the major religious holidays

of Hinduism. People often visit

friends and family during Diwali. They

give each other gifts and eat their favorite

foods, especially sweets. Merchants

perform religious ceremonies and open

new account books in the hope of gaining

wealth.

#More to explore

Hinduism

For many

years Walt

Disney himself

was the voice

of Mickey

Mouse.

An Indian boy lights a lamp during Diwali.

Sometimes people float the lamps on rivers.

58 Diwali BRITANNICA STUDENT ENCYCLOPEDIA

Djibouti

The small Republic of Djibouti shares

the Horn of Africa—a triangle of land

on Africa’s east coast—with Eritrea,

Ethiopia, and Somalia. Its capital is the

port city of Djibouti.

Geography

Djibouti sits between the Red Sea and

the Gulf of Aden. The gulf is a part of

the Indian Ocean. The climate is hot

year-round, and it rarely rains. Much of

the land is bare desert. Dry riverbeds

and salty lakes dot the interior. Mountains

rise in the north.

Plants and Animals

Djibouti’s few plants include thorny

shrubs and grasses. A small forest of

olive, juniper, and acacia trees grows

around Mount Mousa, the country’s

highest point. Millions of flamingos

spend the winter around the salty Lake

Assal. Other animals include hyenas,

jackals, ostriches, antelope, and gazelles.

People

The country’s two largest ethnic groups

are the Issas and the Afars. The Issas are

related to the Somalis of Somalia. The

Afars are of Arabian origin. Nearly all

the people are Muslims. The official

languages are French and Arabic, but

many people speak Somali or Afar. Most

people live in or near Djibouti city.

Economy

Djibouti’s economy depends on transportation

services. Its port is a supply

station for ships traveling through the

Red Sea. A railway connects Djibouti to

Ethiopia. In rural areas people raise

goats and sheep.

History

Hundreds of years ago the region of

Djibouti was part of a Christian Ethiopian

empire. Arab traders brought Islam

to the area in about the AD 800s. Muslims

ruled the region until the 1800s,

when France took control. The colony

of French Somaliland became the

French Territory of the Afars and Issas in

1967. The territory gained independence

as Djibouti in 1977.

In the 1990s Afar rebels fought the Issadominated

government. In the early

21st century warfare and drought in

neighboring countries forced thousands

of people to move to Djibouti.

..More to explore

Djibouti City • Red Sea

Facts About

DJIBOUTI

Population

(2008 estimate)

506,000

Area

8,950 sq mi

(23,200 sq km)

Capital

Djibouti

Form of

government

Republic

Major cities

Djibouti, !Ali

Sabih, Tadjoura,

Dikhil

BRITANNICA STUDENT ENCYCLOPEDIA Djibouti 59

Djibouti

Population

(2005 estimate)

350,000

Djibouti is a city in northeastern Africa

on the Gulf of Aden, a part of the

Indian Ocean. Djibouti is the capital of

a small country that is also named Djibouti.

Most of the country’s people live

in Djibouti city.

Djibouti city has a mixture of old and

modern buildings in African and French

styles. The economy of the city depends

on trade through its port. Transporting

goods on a railway to Addis Ababa,

Ethiopia, also brings money to the city.

Djibouti city began as a port in about

1888. In that year the French built a

station for fueling ships in the harbor. A

city soon rose up. The colony called

French Somaliland grew around the city.

In 1892 Djibouti city became the capital

of the colony.

Djibouti became an independent country

in 1977. Djibouti city was its capital.

The city grew rapidly in the late 20th

century. Many people went there to

escape droughts and wars in nearby

countries.

#More to explore

Djibouti

DNA

DNA is the material that carries all the

information about how a living thing

will look and function. For instance,

DNA in humans determines such things

as what color the eyes are and how the

lungs work. Each piece of information is

carried on a different section of the

DNA. These sections are called genes.

DNA is short for deoxyribonucleic acid.

It is in every cell of every living thing.

DNA is found in structures of the cell

called chromosomes. Chromosomes are

tiny. Scientists need to use very powerful

microscopes to see them.

Functions

When DNA works correctly, it helps

keep the body working properly. DNA

helps cells to make the substances called

proteins, which the cells need to live.

DNA also allows living things to reproduce.

The genes in DNA pass along

traits from parents to children.

Part of a long DNA chain shows the

twisted, ladderlike structure.

60 Djibouti BRITANNICA STUDENT ENCYCLOPEDIA

Sometimes there are mistakes in DNA.

These mistakes are called mutations.

They can cause unusual features, diseases,

and other problems.

Structure

DNA has a complex structure. It is

made of chemical substances that are

linked together like a chain. Each piece

of DNA has two long strands, or chains.

The two strands are joined together.

They form a shape like a ladder that has

been twisted into a spiral.

Chemicals called phosphates and sugars

make up the sides of the ladder. DNA

also has chemicals called bases. Each

base on one strand is joined to a base on

the other strand. The linked bases form

the rungs of the ladder.

Genetic Code

There are four different bases in DNA:

adenine, thymine, guanine, and

cytosine. These four chemicals are

repeated in different orders over and

over again in each strand of DNA.

Human DNA contains about 3 billion

pairs of these bases.

The order in which the bases are

arranged is very important. It forms a

code that tells cells to make certain

kinds of proteins. The differences in

these proteins is what makes different

living things—such as a cactus, a gerbil,

and two different people—different.

#More to explore

Cell • Chromosome • Genetics • Living

Thing • Mutation

Dog

The dog is one of the most popular animals

in the world. It was one of the first

animals to be domesticated, or trained

for use by humans. The dog’s scientific

name is Canis familiaris. It is related to

the coyote, wolves, foxes, and jackals.

Where Dogs Live

People around the world keep dogs as

pets, guards, or work animals. Some

dogs, called feral dogs, do not live with

people. These homeless dogs often roam

around in groups, called packs. One

type of dog, called the dingo, lives in the

wild in Australia.

Physical Features and Breeds

The dog is a mammal with sharp teeth,

an excellent sense of smell, and a fine

sense of hearing. Each of its four legs

ends in a foot, or paw, with five toes.

Each toe has a soft pad and a claw. A

coat of hair keeps the dog warm. It cools

off by panting and hanging its tongue

out of its mouth.

Some dogs are purebred. This means that

both parents were of the same breed. A

dog with parents of different breeds is

called a mutt or mongrel.

BRITANNICA STUDENT ENCYCLOPEDIA Dog 61

Some Breeds of Dog

Breed Origin Height of Males (inches)

Sporting dogs

English cocker spaniel England 16–17

Golden retriever Scotland 23–24

Irish setter Ireland 27

Weimaraner Germany 25–27

Golden retriever

Hounds

Afghan hound Afghanistan 27

Beagle England 13 or 15

Dachshund Germany 7–10

Greyhound Egypt 27–30

Beagle

Working dogs

Great Dane Germany minimum 30

Mastiff England minimum 30

Saint Bernard Switzerland minimum 27.5

Siberian husky northeastern Asia 21–23.5

Siberian husky

Terriers

Bull terrier England 21–22

Miniature schnauzer Germany 12–14

Scottish terrier Scotland 10

Welsh terrier Wales 15–15.5

Scottish terrier

Toys

Chihuahua Mexico 5

Maltese Malta 5

Pomeranian Iceland, Lapland maximum 11

Pug China 10–11

Pug

Non-sporting dogs

Bulldog England 12–14

Dalmatian Croatia 19–23

Lhasa apso Tibet 10–11

Poodle France minimum 15

Dalmatian

Herding dogs

Collie Scotland 24–26

German shepherd Germany 24–26

Old English sheepdog England minimum 22

Pembroke Welsh corgi Wales 10–12

Collie

Dog breeds are placed in seven different groups, according to the original function of the

breed. For example, sporting dogs and hounds hunt animals. Working dogs do such jobs

as pulling sleds or guarding homes. The table shows some dog breeds in each group.

62 Dog BRITANNICA STUDENT ENCYCLOPEDIA

Apart from these common features, dogs

come in many different sizes, shapes,

and colors. Dogs that have similar sizes,

looks, and behaviors make up groups

called breeds.

Behavior

Dogs are carnivores, which means that

they eat meat. Pet dogs eat dog food

made with meat products.Wild dogs

hunt animals.

Dogs claim territory and mark it as their

own. They do this by urinating and rubbing

their scent on things. But dogs also

like to be around people and other dogs.

People can even train dogs to obey

simple commands.

Dogs make many sounds, including

barks, howls, and growls. They also use

movements to communicate. For

example, when a dog wags its tail, it is

happy. If it shows its teeth and growls, it

is making a threat.

Life Cycle

A female dog gives birth to a litter of

puppies about two months after mating.

A litter contains two to 12 puppies.

Newborn puppies depend on their

mother for her milk and protection.

Puppies become more independent

when they are three or four months old.

Dogs live for 10 to 15 years.

Dogs and Humans

Dogs have been with humans since prehistoric

times. The ancient Egyptians

thought dogs were holy. The ancient

Romans kept watchdogs. In the palaces

of ancient China, people kept small dogs

in the sleeves of their robes.

Over the years, people developed different

breeds of dog for different purposes.

Toy dogs, including the poodle and the

pug, were meant to be pets. Other dogs

were meant to do certain jobs. For

example, the golden retriever and other

sporting dogs helped people to hunt

birds. Some of these dogs are now

mainly pets. Others still do their traditional

jobs.

Working dogs do many other jobs today.

Some sniff bags in search of explosives or

drugs.Others track missing people.

Guide dogs help blind people get around.

#More to explore

Coyote • Fox • Jackal • Mammal • Pet

•Wolf

Doha

Population

(2004 estimate)

339,800

Doha is the capital of theMiddle Eastern

country of Qatar. The city lies along a

bay of the Persian Gulf. Doha is Qatar’s

major port and center of business.

People have lived in the Doha area for

thousands of years. Doha developed as a

BRITANNICA STUDENT ENCYCLOPEDIA Doha 63

small fishing village. For many years it

was a base for pirates who sailed in the

Persian Gulf. Doha was destroyed in

1867 during a war, but it was rebuilt.

Great Britain took charge of Qatar’s

foreign affairs in 1916. Oil was discovered

in the region in the 1930s. Qatar

used some of its oil wealth to make

Doha more modern. In 1971 Qatar

became an independent country. Doha

became its capital.

#More to explore

Qatar

Dolphin

Dolphins look like big fishes, but they

are actually mammals. They belong to a

large group of animals called whales.

Dolphins are closely related to porpoises.

Because dolphins and porpoises

look so much alike, people often confuse

the two. However, dolphins are usually

larger and have longer, beaklike snouts.

There are more than 35 species, or

types, of dolphin. They are divided into

two groups: true dolphins and river dolphins.

True dolphins live throughout the

world in either salt water or freshwater.

The most widespread species are the

common dolphin and the bottlenose

dolphin. River dolphins live in freshwater

in South America and Asia.

Most dolphins are 7 to 10 feet (2 to 3

meters) long, but some species can reach

a length of 13 feet (4 meters). Dolphins

have smooth, rubbery skin. They have a

flipper on each side and a fin on the

back. A dolphin must come up to the

water’s surface to get air. It breathes

through a single nostril, called a blowhole,

on the top of its head.

Dolphins are known for being intelligent

and playful. They live together in

groups, called schools. They use sounds

to communicate.

Female dolphins give birth to one baby,

or calf, at a time. Some types of dolphin

may live for 30 years.

#More to explore

Fish • Mammal • Porpoise • Whale

Traditional Qatari ships sail past a modern

hotel in Doha.

Although dolphins look like fish and live in

the water, they are actually mammals.

64 Dolphin BRITANNICA STUDENT ENCYCLOPEDIA

Dominica

The Commonwealth of Dominica is a

small island republic in the Caribbean

Sea. Christopher Columbus named the

island after the Latin phrase dies

dominica, which means “the Lord’s day.”

Columbus had first spotted the island

on a Sunday. Dominica’s capital and

largest city is Roseau.

Geography

Dominica lies between the French

islands of Guadeloupe and Martinique.

It is about 29 miles (47 kilometers) long

and less than 16 miles (26 kilometers)

wide. A forest-covered mountain range

runs from north to south. Dominica has

a hot climate with dry and rainy seasons.

Plants and Animals

The Dominican jungle may be the last

original rain forest in the Caribbean. It

is filled with iguanas, boa constrictors,

rabbit-sized rodents called agoutis, and

large frogs called crapauds. Imperial

parrots and red-necked parrots live only

in Dominica.

People

Most Dominicans are descended from

Africans. There are also small groups of

whites, Asians, and Caribs (American

Indians). English is the official language,

but a form of French is commonly spoken.

Most Dominicans are Roman

Catholics. Almost three fourths of the

population lives in cities.

Economy

Dominica is one of the poorest Caribbean

countries. Its economy depends on

farming, and hurricanes sometimes

destroy the crops. Bananas are the main

crop. Other crops include root vegetables,

citrus fruit, and coconuts.

Manufacturers produce mainly soap,

toothpaste, and coconut oil. Dominica’s

main mineral resource is pumice, a type

of volcanic rock.

History

In 1493 Columbus arrived at Dominica,

which was inhabited by Caribs. The

French set up a colony there in the

1630s. Settlers later brought Africans to

work on plantations as slaves. Great

Britain won control in 1783. In 1978

the island became independent. Since

then Dominica’s leaders have worked to

improve the economy.

..More to explore

Caribbean Sea • Roseau

Facts About

DOMINICA

Population

(2008 estimate)

72,500

Area

290 sq mi (750

sq km)

Capital

Roseau

Form of

government

Republic

Major towns

Roseau, Portsmouth,

Marigot,

Atkinson, Mahaut

BRITANNICA STUDENT ENCYCLOPEDIA Dominica 65

Dominican Republic

The Dominican Republic is located on

the island of Hispaniola in the Caribbean

Sea. The people are known for

their merengue dance and their passion

for baseball. The capital is Santo Domingo.

Geography

Hispaniola lies between the islands of

Cuba and Puerto Rico. The Dominican

Republic occupies the eastern two thirds

of Hispaniola. Haiti occupies the western

third. The island has fertile valleys,

desertlike areas, and four mountain

ranges. Duarte Peak, at 10,417 feet

(3,175 meters), is the highest mountain

in theWest Indies. The country has a

tropical climate with warm temperatures

year-round.

Royal palm trees grow throughout the

Dominican Republic. Rain forests occur

in the wetter areas. The country’s wildlife

includes alligators and many birds.

People

Most Dominicans have mixed European

and African roots. Spanish is the main

language. The majority of the population

is Roman Catholic. Most people

live in cities and towns.

Economy

Services—including tourism and

telecommunications—are the main economic

activities. Manufacturers make

cement, sugar, beer, clothing, and cigars.

Farmers grow sugarcane, rice, bananas,

cocoa, and coffee. The country also has

deposits of nickel and gold.

History

Christopher Columbus discovered Hispaniola

in 1492. In 1496 the Spanish

founded Santo Domingo.Within

decades most of the native Carib and

Taino peoples had died. The Spanish

brought in slaves from Africa.

France gained control of Hispaniola in

1795. Haiti won independence from

France in 1804. Spain took back control

of eastern Hispaniola, but the Dominicans

declared independence in 1821.

Soon afterward the Haitians invaded.

The Dominican Republic achieved independence

from Haiti in 1844. It then

alternated between weak democracies

and governments led by dictators.

..More to explore

Haiti • Santo Domingo

Facts About

DOMINICAN

REPUBLIC

Population

(2008 estimate)

9,507,000

Area

18,792 sq mi

(48,671 sq km)

Capital

Santo Domingo

Form of

government

Republic

Major urban

centers

Santo Domingo,

Santiago, La

Romana, San

Francisco de

Macoris, San

Cristobal

66 Dominican Republic BRITANNICA STUDENT ENCYCLOPEDIA

Donkey

The donkey is a member of the horse

family. The words donkey and ass are

used to identify the same animal. However,

the term donkey is used for domesticated,

or tamed, animals. The term ass

is more often used when the animal is

wild. Donkeys are descendants of the

African wild ass. They were first domesticated

by humans in Africa. They are

now used around the world as working

animals.

The average donkey stands 40 inches

(102 centimeters) at the shoulder, but

different breeds vary greatly in size and

shape. Donkeys range from white to

gray or black in color. They usually have

a dark stripe from the mane to the tail

and a crosswise stripe on the shoulders.

The mane is short and upright, and the

tail has long hair only at the end. The

ears are very long and are dark at the

base and tip. A donkey can carry heavy

loads over rough land. The donkey can

handle the uneven ground of the mountains

better than a horse can.

On average female donkeys give birth 12

months after mating. Donkeys sometimes

breed with horses to produce animals

called mules. Donkeys can live up

to 50 years.

#More to explore

Horse

Douglass,

Frederick

His brilliant speaking and writing made

Frederick Douglass a leader of the movement

to abolish slavery. A former slave

himself, Douglass was also the first African

American citizen to hold an important

position in the U.S. government.

Early Life

Frederick AugustusWashington Bailey

was born sometime in 1817 or 1818 in

Talbot County, Maryland. His mother

was a slave. He never knew his father,

who was a white man.

A farmer leads a donkey and cart across a

plowed field.

Frederick Douglass

BRITANNICA STUDENT ENCYCLOPEDIA Douglass, Frederick 67

At the age of 8, Frederick was sent to

live in Baltimore as a house servant with

the family of Hugh Auld. Auld’s wife,

Sophia, taught Frederick to read.

In 1838 Frederick escaped to New York

City, where he lived as a free man. He

married Anna Murray of Baltimore, a

free woman. They settled in New Bedford,

Massachusetts, and Frederick

changed his last name to Douglass.

AntislaveryWork

At an antislavery convention in 1841 in

Nantucket, Massachusetts, Douglass was

invited to describe his experiences as a

slave. His moving speech marked the

beginning of his career as an abolitionist.

Douglass was so impressive as a speaker

that some of his critics doubted that he

could ever have been a slave. Douglass

addressed these critics in 1845 by publishing

his autobiography, The Narrative

of the Life of Frederick Douglass, an

American Slave.

In 1847 Douglass founded an antislavery

newspaper in Rochester, New York,

called The North Star. While in Rochester,

Douglass helped to smuggle escaped

slaves to Canada via the Underground

Railroad.

Later Life

During the American CivilWar Douglass

was a consultant to President Abraham

Lincoln. Douglass suggested that

former slaves should be given weapons

to fight for the North.

After the CivilWar, Douglass held several

government offices. He also continued

to fight for human rights until he

died inWashington, D.C., on February

20, 1895.

..More to explore

Abolitionist Movement • Slavery

• Underground Railroad

Dover

Population

(2000 census)

32,135; (2007

estimate)

35,811

Dover is the capital of the U.S. state of

Delaware. The city is located on the

Saint Jones River.

Dover is a farm trade center. Crops are

brought to the city from nearby farms

One of the important state government

buildings in Dover is Legislative Hall.

During the

American Civil

War Douglass

organized two

black Army

units. He also

tried to get

equal pay for

black soldiers.

68 Dover BRITANNICA STUDENT ENCYCLOPEDIA

and are shipped out from there. Factories

in the city package foods and make

paints, rubber products, and perfumes.

Many people in Dover work for the state

government.

In 1682 William Penn took control of

the colony of Delaware. A year later he

ordered a new town to be created. The

town was not actually built until 1717.

It was named after Dover, England.

Dover replaced the city of New Castle as

the capital of Delaware in 1777.

#More to explore

Delaware • Penn,William

Down Syndrome

Down syndrome is a disorder, or

unusual condition, that can cause delays

in a child’s development. About 1 in

800 babies is born with Down syndrome.

Down syndrome happens when

an infant’s cells have 47 instead of 46

chromosomes. (Chromosomes are tiny

structures in a cell that carry information

about people, such as what color

eyes and hair they will have.)

Having an extra chromosome can cause

developmental disabilities. This means

that people with Down syndrome may

have trouble learning or taking care of

themselves. They may have certain

medical problems, too. Some of the

most common problems are heart

defects and problems with hearing,

vision, digestion, and the thyroid gland.

Most people with Down syndrome get

special medical care from the time they

are babies.

In the past many children with Down

syndrome lived in special homes apart

from their families. Today most people

with Down syndrome grow up in their

parents’ homes. They make friends, go

to school, and play sports. As adults

many people with Down syndrome have

jobs. They often live in group homes or

apartments.

#More to explore

Child Development • Chromosome

• Disability

Dragon

#see Animals, Legendary.

Dragonfly

Dragonflies are flying insects with two

pairs of see-through wings, huge eyes,

and long bodies. Dragonflies live near

lakes, streams, and ponds throughout

most of the world. There are about

2,500 species, or types, of dragonfly.

A girl with Down syndrome plays the guitar.

BRITANNICA STUDENT ENCYCLOPEDIA Dragonfly 69

The insects vary greatly in color. They

also range widely in size. The smallest

dragonflies have wingspans about 0.8

inch (20 millimeters) across. The largest

ones have wingspans about 6 inches (15

centimeters) across. Dragonflies’ wings

stand out sideways from their bodies

even when they are resting.

Adult dragonflies feed mostly on other

insects, and their bodies make them

deadly hunters. Dragonflies fly faster

than most other insects. They can also

instantly change the direction of their

flight and hover like tiny helicopters.

Their large eyes allow them to spot prey

above, below, in front, behind, and on

both sides of them.

Dragonflies hatch from eggs in or near

bodies of freshwater. They hatch as larvae,

or undeveloped forms that do not

look anything like the adults. Dragonfly

larvae live in water. They are fierce hunters

and use a pair of fanglike pincers to

catch worms, tadpoles, and small fish.

The larvae grow quickly and shed their

skin several times. During this time they

develop adult features. Eventually, the

larvae crawl out of the water. They shed

their skin one last time and fly away as

adult dragonflies.

#More to explore

Insect

Drake, Francis

The navigator Sir Francis Drake helped

to build up England’s power during the

reign of Queen Elizabeth I. He opened

the Pacific Ocean to English ships. He

also helped defeat the Armada, the fleet

(group of ships) that Spain sent to conquer

England.

Francis Drake was born in about 1540.

At about age 13 he first worked as a

sailor. In his early 20s he joined a slavetrading

fleet. Off the coast of Mexico,

the Spanish attacked the fleet. Drake

disliked the Spanish from that time on.

A brightly colored dragonfly pauses for a

rest.

Francis Drake

70 Drake, Francis BRITANNICA STUDENT ENCYCLOPEDIA

Dramas are commonly called plays.

Other forms of literature, such as novels

and short stories, are meant to be read

by individuals. But through staged productions

dramas are shared with many

people at once.

Elements of Drama

A person called a playwright, or a dramatist,

writes the play’s text. The major

elements of a play, or drama, include the

characters and the plot. The characters,

or the people in the story, often come

into conflict with each other over something.

For example, they may desire the

same throne, princess, or treasure. The

plot is what happens during the play

and how the conflicts are settled.

In a play the characters use their words

and movements to tell the story. Often

the characters talk to each other. The

words of their conversations are known

as dialogue. Sometimes, however, a character

will make a speech while alone

onstage or with the other characters

silent. This creates the illusion that the

audience can hear the character’s

thoughts. That kind of speech is called a

soliloquy. Occasionally a character will

speak directly to the audience. That is

called an aside.

A playwright might write dialogue that

sounds natural, or how people of a particular

time and place actually talk. Or

the dialogue may be very formal. For

instance, sometimes the characters’

words are written in poetry. In some

dramas the characters may sing or chant

their words.

The playwright also writes short instructions,

called stage directions, in the text.

Some stage directions tell the actors

what to do, such as when and where to

enter the stage. Other directions may

describe what a character looks like.

They may also indicate the time and

place of the action. The play’s designers

use these descriptions to create the scenery,

costumes, and lighting.

Dramatic Traditions

Different dramatic traditions developed

in Asia and theWest (Europe and North

America). In the dramas of many cul-

The characters of Captain Hook and Peter

Pan fight with their swords.

Fun costumes bring the characters to life in

a performance of Where the Wild Things

Are by Maurice Sendak.

72 Drama BRITANNICA STUDENT ENCYCLOPEDIA

tures in Asia, dance, gestures, and music

are often as important as the words.

Asian dramas often use familiar stories as

a base. They also tend to have a formal

style. The actors may follow a set of

rules about the facial expressions and

body movements they use to tell the

story.

On the other hand, Western dramas

tend to focus on telling a new story

through dialogue. Traditionally, Western

dramas have been divided into two

broad types: tragedies and comedies.

Tragedies are serious stories about

heroic individuals. They have a sad

ending. Comedies are less serious and

have a happy ending. Modern comedies

are often funny. Today many Western

dramas mix elements of tragedy and

comedy.

History

Early Forms

Scholars believe that drama dates back

to the time of the earliest peoples.

Drama probably began as part of religious

festivals and ceremonies. These

took place in many cultures, including

those of ancient Egypt, India, and

China.

Western drama has its roots in ancient

Greece. The great age of Greek drama

was the 400s BC. Greek drama was written

in poetry. A few actors portrayed all

the play’s characters. Greek playwrights

also wrote parts for a group called the

chorus. The chorus stood off to the side

and described and explained the action.

Greek tragedies told about important

people and events from legends or history.

The comedies from this period

often made fun of the day’s political figures.

During the Middle Ages (AD 500–1500)

in Europe most drama was based in

Christianity. Some plays of the period

told stories from the Bible. Others dramatized

the lives of Christian saints or

presented a moral lesson.

In the 1300s in Japan a new form of

drama, called Noh, developed. A Noh

drama presents classical Japanese legends

using movement, music, and words.

About 230 of the classical Noh stories

are still performed today. A man named

Zeami wrote 90 of them. He is considered

the greatest Noh playwright.

The 1500s and 1600s were a great

period for drama in England and Spain.

Playwrights wrote in a wide range of

styles. The greatest playwright of this

period was William Shakespeare of

England. He wrote complex, actionfilled

plays with realistic characters.

Actors perform in William Shakespeare’s A

Midsummer Night’s Dream.

BRITANNICA STUDENT ENCYCLOPEDIA Drama 73

In the 1600s Jean Racine and other

French dramatists wrote plays set in

ancient Greece. Their plays featured

grand themes and poetic language. The

French playwright Moliere wrote a different

type of play. His comedies poked

fun at the fashions and faults of French

society of the time.

In the 1700s in Japan a type of puppet

theater called Bunraku reached its artistic

height. A man named Chikamatsu

Monzaemon wrote Bunraku plays that

were admired as both literature and

entertainment. He wrote historical

romances as well as tragedies about ordinary

people of his time.

Modern Drama

In the 1800s and early 1900s many

Western plays focused on ordinary

people rather than kings, warriors, or

legendary heroes. These plays explored

the characters’ inner struggles. Many

plays also dealt with social problems,

such as corruption and greed in society.

Henrik Ibsen of Norway and Anton

Chekhov of Russia wrote plays in this

realistic style. In England George Bernard

Shaw used humor to attack society’s

problems. Eugene O’Neill of the

United States used some of the themes

of ancient tragedies. But he placed them

in more modern times among everyday

characters.

AfterWorldWar II ended in 1945 many

people felt discouraged about the state

of the world. Some European playwrights

wrote plots and dialogue that

made little sense. This was meant to

show that life is ridiculous. Their plays

came to be known as Theater of the

Absurd.

Other playwrights continued to explore

familiar topics. In the United States

Arthur Miller wrote dramas that focused

on the inner lives and family conflicts of

strong characters. Similar themes

appeared in the plays of TennesseeWilliams.

Williams often set his plays in the

southern United States.

In the late 20th and early 21st centuries

playwrights of many different backgrounds

began to produce notable dramas.

Starting in the 1960s several

African American dramatists, such as

AugustWilson, became successful.

Social problems and the conflicts of

ordinary people continued to provide

material for playwrights. But many playwrights

also experimented with bold,

fresh ways of telling their stories.

#More to explore

Dance • Literature • Music

• Shakespeare,William • Storytelling

• Theater

August Wilson’s play The Piano Lesson is

about the African American experience in

the United States.

74 Drama BRITANNICA STUDENT ENCYCLOPEDIA

Drawing

Drawing is a form of art. To make a

drawing, an artist puts lines on paper or

another surface. Most artists start out by

learning to draw. This is because drawing

is the starting point for painting,

sculpture, and other art forms.

Drawing Tools

Artists can choose from many tools for

drawing. Pencils, pens, and pastels are

common drawing tools. Artists’ pencils

come in a wide range of hardness. Softer

pencils make darker marks. Artists’ pens

may have different tips for making wide

or thin lines. Some artists use special

pens that they dip in ink before drawing.

Pastels are chalklike sticks made of

colored powder. Other drawing tools

include charcoal, crayons, and chalk.

Paper is by far the most common surface

for drawing. Paper comes in many colors

and textures. Artists often use smooth

paper for fine drawing.

Many artists today use computers to

create drawings. Special software allows

artists to draw with a mouse or a drawing

pad.

How Artists Draw

Drawings are usually made up of lines.

An artist can put lines together to form

figures, or pictures of things. Artists also

can use lines to stand for borders

between a figure and the space that surrounds

it.

To create shadows, an artist can combine

or cross lines. In a technique called

hatching, an artist draws short, parallel

lines to make light and dark areas. In a

technique called crosshatching, an artist

uses two sets of parallel lines that cross

each other.

Not all drawings are made with just

lines. Artists often fill in parts of their

drawings by rubbing their drawing tools

across the drawing surface. This technique

creates shadows or areas of solid

color. Some artists uses spots and dots to

fill in areas or to create forms.

History

People have been drawing since prehistoric

times. Prehistoric people drew on

cave walls, on rocks, and probably on

sand. Early drawings eventually developed

into writing. Ancient Egyptian

writing, called hieroglyphics, was a system

of picture symbols. Many of the

characters in Chinese writing also were

drawings at first.

The drawing

ink called

India ink is

made from the

soot of burning

wood or

burning oil.

Many artists draw with charcoal. Charcoal

is made from partially burned, or charred,

wood.

BRITANNICA STUDENT ENCYCLOPEDIA Drawing 75

Chinese artists made ink drawings as

early as 3,000 years ago. By about 1,000

years ago the Chinese drew on scrolls, or

long, rolled pieces of paper or silk. Asian

artists generally used brushes instead of

pens to make ink drawings.

Drawing in Europe became a form of

fine art during the Renaissance. The

Renaissance was a time of great culture

that lasted from the 1300s through the

1500s. Artists in Italy—including

Leonardo da Vinci, Raphael, and

Michelangelo—made many fine drawings.

Da Vinci created drawings of the

human body as well as scientific drawings.

In Germany the artist Albrecht

Durer made detailed pen-and-ink drawings

of religious subjects.

Later European artists made drawings

that showed their opinions. In the 1700s

the English artistWilliam Hogarth

made drawings that made fun of human

mistakes. In the 1800s the Spanish artist

Francisco Goya made drawings that

showed the horrors of war.

In the 1900s many artists made drawings

that looked less realistic than earlier

drawings. They used geometric shapes or

free-flowing lines to represent people

and objects. Some artists made abstract

drawings, or drawings that did not represent

anything. These drawings were

meant to express emotions or ideas. The

Spanish artist Pablo Picasso made some

of the greatest drawings of this period.

Today drawing is still a popular form of

art. But people also use drawing for

many business and entertainment purposes.

Advertisers use drawings to sell

products. Fashion artists and designers

of products use drawings to plan their

work. Illustrators and cartoonists draw

pictures for books, newspapers, and

magazines. In addition, many children

and adults draw just for fun or relaxation.

#More to explore

Arts • Cartoon • Painting • Sculpture

Dred Scott

Decision

In 1857 the U.S. Supreme Court ruled

that Congress had no power to ban slavery

in the territories, or areas that were

not yet states. The ruling, called the

Dred Scott decision, increased tensions

between the proslavery South and the

antislavery North.

Many children draw on sidewalks with

chalk. When it rains, the drawings are

washed away.

76 Dred Scott Decision BRITANNICA STUDENT ENCYCLOPEDIA

Dred Scott was a black slave in Missouri.

In 1834 he was taken to Illinois.

Illinois was a free state, meaning that

slavery was illegal there. Scott later lived

in the territory ofWisconsin, where

slavery was also illegal. When Scott was

taken back to Missouri, he sued for his

freedom. He argued that the time he

had spent in a free state and a free territory

had made him free.

Scott’s court case began in Missouri

and made its way up to the U.S.

Supreme Court. The court ruled against

him. In fact, the court said that he did

not even have the right to file a lawsuit.

The court also changed an earlier law

that had banned slavery in territories

north of Missouri. This angered people

who were against slavery. The issue of

slavery grew to be so much of a

problem that it led to war between the

states in 1861. The defeat of the South

in the American Civil War finally ended

slavery.

#More to explore

American CivilWar • Slavery • United

States Government

Drought

Wherever there is a shortage of rain over

a long period of time, there is drought.

Drought affects plants, animals, and

people. It is a serious problem for farmers

and for the people who depend on

the crops they produce.

Drought may occur almost anywhere in

the world. Deserts receive very little rain

all year. They are sometimes said to be in

a permanent drought. Places that have a

rainy season and a dry season have seasonal

drought during the dry season.

Other places can experience drought at

any time.

Drought results from changes in Earth’s

atmosphere. Some droughts are caused

by shifts in the winds that normally

bring rain to an area. Others are caused

by changing ocean currents, which

affect the temperature and moisture of

the air.

Severe droughts can last for months or

years. When this happens no crops will

grow. As a result many people and animals

may die of famine, or lack of food.

Severe droughts often force people and

animals to move to find water. Some

farmers go to places where they think

conditions will be better for their crops

Drought can

lead to dust

storms. When

soil dries out

and cracks it

can be blown

away by wind.

Dred Scott was a slave who sued for his

freedom. He did not win his court case.

BRITANNICA STUDENT ENCYCLOPEDIA Drought 77

and animals. Some people give up farming

altogether. They move to cities to

find other types of work.

#More to explore

Atmosphere • Desert • Famine

Drug

A drug is a substance that changes the

way a person’s body works. Medical

drugs can ease the symptoms of illnesses

and fight diseases. Some people also use

certain kinds of drugs for nonmedical

purposes.

How DrugsWork

Some drugs work by changing the way

cells in the body behave. For example, a

chemical in the body called histamine

causes the symptoms of allergies. Drugs

called antihistamines ease these symptoms.

The drugs do this by joining with

cells to block the histamine.

Other drugs attack living things that

invade the body—for example, bacteria

and parasites. Drugs can kill these

organisms, stop them from reproducing,

or block their effects.

Medical Drugs

Patients get drugs from doctors or from

pharmacies. Pharmacies can give certain

drugs to patients only after a doctor

orders them. Doctors’ orders for drugs

are called prescriptions. Patients can

also buy some drugs without

prescriptions—for example, aspirin and

cough syrup.

Drug manufacturers must prove that

their drugs are safe and that they work

before they can be sold. In the United

Cracked, dry dirt covers marshland in a drought region of California.

78 Drug BRITANNICA STUDENT ENCYCLOPEDIA

States the Food and Drug Administration

studies all drugs before they can be

sold there.

Illegal Drugs and Drug Abuse

Many governments around the world

have banned the use of certain drugs—

for example, marijuana, cocaine, LSD,

heroin, and Ecstasy. These illegal drugs

are generally not used as medicine.

People often take illegal drugs for fun

but ignore the harmful side effects. They

may become addicted, or unable to stop

taking the drugs. They may get sick or

even die.

Such dangerous use of illegal drugs is

called drug abuse. People can abuse legal

drugs, too. They may take medication

when they are not really sick, or they

may take too much.

History

Throughout history almost every society

has used drugs for medicine and for

rituals. Early people made drugs from

plants, animals, and minerals that they

found in nature. Eventually scientists

learned how to take different chemicals

out of those natural materials. They

studied what those chemicals did to the

body and decided which illnesses they

could treat. From those chemicals they

created drugs.

..More to explore

Bacteria • Disease, Human • Parasite

Dublin

Population

(2006 census),

city, 506,211;

urban area,

1,186,159

Dublin is the capital of Ireland, a country

in western Europe. The city lies on

the Irish Sea. The River Liffey flows

through the middle of Dublin.

Dublin is the largest city in Ireland by

far. It is also the center of Ireland’s

economy and culture. Trinity College

was founded in Dublin in 1592. It is

Ireland’s oldest university.

Dublin’s economy grew greatly in the

early 21st century. Most people in Dublin

work in service industries such as

Pain relievers, such as aspirin, are a very

popular type of drug. Store shelves are

crowded with the many different brands.

BRITANNICA STUDENT ENCYCLOPEDIA Dublin 79

tourism and banking. The city is one of

Europe’s leading producers of computer

software. Factories in Dublin make electronics,

food products, beer, and medicines.

The city is also the main port of

Ireland.

Vikings from what is now Denmark

founded Dublin in the 800s. In 1014 an

Irish group took over the city. The

English started taking control of Ireland

in 1170. They made Dublin the center

of the English government in Ireland.

In 1801 Ireland was joined to England,

Scotland, andWales to form the United

Kingdom. As a result Ireland’s lawmakers

began to meet in London, England,

instead of Dublin. Dublin lost some of

its importance.

Irish groups began to rebel against

English rule in the mid-1800s. Dublin

was often the site of violence. In 1921

Ireland became an independent country

with Dublin as its capital.

#More to explore

Ireland

Du Bois,W.E.B.

W.E.B. Du Bois was an early leader of

the civil rights movement in the United

States. His goal was to win equal rights

for African Americans.

William Edward Burghardt Du Bois was

born on February 23, 1868, in Great

Barrington, Massachusetts. He went to

Fisk University and to Harvard University.

He earned a doctoral degree at Harvard

in 1895.

Du Bois became a professor who studied

and wrote about black life in the United

States. His most famous book, The Souls

of Black Folk, encouraged blacks to fight

inequality.

Du Bois disagreed with Booker T.Washington,

another important African

American leader.Washington opposed

protest as a way to change society. Du

Dublin Castle lies on Cork Hill near the

river. The English used the castle as their

headquarters until 1922.

W.E.B. Du Bois

80 Du Bois, W.E.B. BRITANNICA STUDENT ENCYCLOPEDIA

Bois believed that blacks could achieve

racial equality only through protest.

In 1905 Du Bois began organizing

groups to demand equal rights for

blacks. In 1909 he helped form the

National Association for the Advancement

of Colored People (NAACP).

Late in life Du Bois lost hope that the

United States could solve its racial

problems. He became a citizen of

Ghana, inWest Africa, in 1963. He died

there on August 27, 1963.

#More to explore

Civil Rights • National Association for

the Advancement of Colored People

•Washington, Booker T.

Duck

The waterbirds called ducks are related

to geese and swans. There are about 100

species, or types, of duck. They are

found almost all over the world. Many

types migrate, or fly long distances to

spend different seasons in different

regions. People keep ducks for their

meat, eggs, and feathers. Some hunters

shoot ducks for sport.

Physical Features

Ducks, geese, and swans are called

waterfowl in North America and wildfowl

in Europe. These birds have stout

bodies and webbed feet. Soft inner

feathers called down protect them from

cold. A gland near the tail produces oil.

This oil helps protect the outer feathers

from water.

Ducks are the smallest of the waterfowl.

For instance, the mallard is a fairly large

duck at about 24 inches (61 centimeters)

long. Ducks’ legs are set far back on

their bodies. This helps them swim well

but makes them waddle when walking.

Female ducks have mainly brown or

gray feathers year-round. The males look

like the females for part of the year. But

most males have more colorful feathers

during the breeding season. For

example, breeding male mallards have

shiny green heads.

Behavior

Many types of duck feed at the water

surface. They dip their heads below the

surface while tipping up their tails.

These ducks are called dabbling ducks.

They eat mainly plants and insects.

They include mallards, black ducks,

teals, pintails, and shovelers.

Many ducks nest on the ground near

water. Perching ducks are dabbling

ducks that nest in trees. They include

the wood duck and the mandarin duck.

Ducks that dive deep into the water are

called diving ducks. Some types eat

mostly fish and live on the open seas.

The male mandarin duck is known for its

colorful markings.

BRITANNICA STUDENT ENCYCLOPEDIA Duck 81

These sea ducks include mergansers,

scoters, and eiders. Other diving ducks

stay close to shore.

#More to explore

Bird • Goose •Migration, Animal • Swan

Duncan, Isadora

In the early 1900s the dancer Isadora

Duncan created a new form of dance.

Duncan rejected the strict rules of

ballet, which was the main form of

dance at the time. Duncan’s free style

of dancing came to be known as

modern dance.

Duncan was born in San Francisco,

California, on either May 26, 1877, or

May 27, 1878. She was one of four children

raised by their mother, a poor

music teacher. At first her name was

Angela Duncan. While in her teens she

changed her first name to Isadora.

Duncan learned ballet as a child. However,

ballet’s rigid movements did not

please her. She soon began to invent a

more natural way to express herself

through dance. Duncan performed in

New York City and Chicago, Illinois,

but she did not have much success. At

age 21 she left for Europe.

Duncan’s dancing fascinated European

audiences. She danced to classical

music, just as ballet dancers did. But

Duncan made up many of her moves

during each performance. She was the

first Western dancer to perform

barefoot and without tights. She wore a

loose dress based on ancient Greek

costumes.

Duncan eventually opened dance

schools in France, Germany, the United

States, and the Soviet Union. She taught

her students how to follow the natural

movements and rhythms of their bodies.

Duncan’s ideas inspired many future

generations of modern dancers.

In 1922 Duncan married a poet from

the Soviet Union. Many people in the

United States feared the Soviets. Some

accused Duncan of being disloyal to the

United States. She then left her home

country for good. Duncan died in Nice,

France, on September 14, 1927.

#More to explore

Ballet • Dance

Dune, Sand

#see Sand Dune.

Isadora Duncan based her dancing on

natural rhythms and movements.

82 Duncan, Isadora BRITANNICA STUDENT ENCYCLOPEDIA

Du Sable, Jean-

Baptist-Point

Jean-Baptist-Point du Sable was an African

American trader. He was the first

non-Native American to settle in what is

now Chicago.

Du Sable was born around 1745 or

1750 in Saint-Domingue (now Haiti).

His father was French-Canadian and his

mother was a slave from Africa. In 1764

he moved to the French territory of

Louisiana. He later settled in what is

now Peoria, Illinois, where he married a

Native American woman of the Potawatomi

tribe.

In the 1770s the Du Sables settled near

the southern shore of Lake Michigan.

The Native Americans called the area by

a name that is now spelled Chicago.

There Du Sable established a successful

trading post where he sold supplies and

food.

In 1800 Du Sable sold out and moved

to Missouri, where he continued as a

farmer and trader until his death. But

his 20-year residence on the shores of

Lake Michigan had established his title

as Father of Chicago. Du Sable died in

Saint Charles, Missouri, on August 28,

1818.

..More to explore

Chicago

Dushanbe

Population

(2007 estimate)

660,900

Dushanbe is the capital of Tajikistan, a

country in central Asia. The city lies

Jean-Baptist-Point du Sable

A monument in Dushanbe, Tajikistan, celebrates

the city’s history.

BRITANNICA STUDENT ENCYCLOPEDIA Dushanbe 83

along the Varzob River. It is the country’s

center of transportation and industry.

Factories in the city make cloth,

electric cable, and refrigerators.

People have lived in the Dushanbe area

since ancient times. It developed into a

small market village. The Soviet Union

took over the area in 1920. The Soviets

built a new city at the site to be a

regional capital. In 1929 the city was

named Stalinabad. It was renamed Dushanbe

in 1961. Tajikistan became an

independent country in 1991 with Dushanbe

as its capital.

#More to explore

Tajikistan

Dust Bowl

The worst drought (lack of rain) in U.S.

history hit the southern Great Plains in

the 1930s. High winds stirred up the

dry soil. This caused huge dust storms

that ruined farmland. The affected

region came to be known as the Dust

Bowl. It included southeastern Colorado,

western Kansas, the panhandles of

Texas and Oklahoma, and northeastern

New Mexico.

Human mistakes made the drought

worse. DuringWorldWar I (1914–18)

farmers planted new fields of wheat.

Their plows removed grasses that had

held the soil in place. Cattle grazing on

ranches removed more grass. The loss of

the grass cover loosened the soil.

Winds blew soil away in dust storms

called “black blizzards.” The storms

blocked out the sun and piled dirt in

drifts. Some dust storms swept across

the country to the East Coast.

During the drought, fields produced

only one fourth as much wheat and corn

as before. Farmers struggled even more

because the drought came during the

Great Depression. The depression was a

time of great economic hardship. People

whose farms were ruined could not find

other jobs. Many moved to California,

where farms were still operating.

The U.S. government helped the Dust

Bowl area recover.Workers in government

programs planted grass and trees

to keep soil in place. A government

agency taught farmers better farming

methods. Near the end of the 1930s

rainfall finally increased. By the early

1940s the fields in the Dust Bowl area

were productive again.

#More to explore

Drought • Great Depression

A lack of rain and strong winds ruined

farmland and created the region known as

the Dust Bowl in the 1930s.

84 Dust Bowl BRITANNICA STUDENT ENCYCLOPEDIA

Mammals are the only animals

that have ear parts on the outside

of the body.

(See Ear.)

The first Earth Day was celebrated

in the United States in

1970.

(See Earth Day.)

A solar eclipse happens when

the Moon comes between Earth

and the sun.

(See Eclipse.)

The Eiffel Tower was built in

1889 for a fair to celebrate the

100-year anniversary of the

French Revolution.

(See Eiffel Tower.)

More than 12 million people

passed through the U.S. immigration

center on Ellis Island

between 1892 and 1924.

(See Ellis Island.)

Ee

Eagle

Eagles are large birds of prey, meaning

that they hunt and eat animals for food.

They are related to hawks, falcons, and

vultures. Eagles have long held a special

place in the human imagination because

of their strength and soaring flight. The

golden eagle has been a symbol of power

since ancient times. The bald eagle is the

national symbol of the United States.

Eagles are found nearly all over the

world in many different habitats. There

are more than 50 species, or types, of

eagle. All are excellent hunters because

of their keen eyesight, strong claws, and

hooked beak. Different types of eagle eat

a great variety of animals. Their prey

ranges from fish, birds, or snakes to rabbits,

foxes, monkeys, and even deer.

Female eagles are generally larger than

males. A female bald eagle may be as

long as 43 inches (1.1 meters). A male

bald eagle is about 36 inches (0.9 meter)

long. Golden eagles are similar in size.

The main groups of eagles are sea eagles,

booted eagles, forest eagles, and serpent

eagles. Sea eagles snatch fish out of rivers,

lakes, or seas. The bald eagle is a

type of sea eagle that lives in North

America. It is not actually bald. It has

brown body feathers with white feathers

on its head and neck.

The golden eagle is found in North

America, Europe, Asia, and northern

Africa. It is a type of booted eagle, which

has feathers on its legs. The golden eagle

is dark brown with golden feathers on its

head and neck.

Forest eagles are huge birds that live in

rain forests. Serpent eagles are snakeeating

birds of Asia and Africa.

#More to explore

Bird • Bird of Prey • Falcon • Hawk

• Vulture

Ear

Ears are the organs, or body parts, in

humans and many other animals that

allow them to hear. Ears work by picking

up vibrations (tiny back-and-forth

movements), usually in the air or water.

Then they change the vibrations into

signals that the brain understands as

sound. Ears also help an animal to keep

its body in balance.

The Human Ear

Humans have two ears, one on each side

of the head. Each ear has three sections:

the outer ear, the middle ear, and the

inner ear.

The bald eagle was once endangered, or at

risk of dying out. Laws protecting the bird

helped to raise the number of bald eagles

in the wild.

86 Eagle BRITANNICA STUDENT ENCYCLOPEDIA

The outer ear is divided into two main

parts: the auricle and the ear canal. The

auricle is the part of the ear that is visible

on the sides of the head. It is made of a

tough material called cartilage. It collects

sound waves and sends them into a

curved passageway called the ear canal.

The ear canal leads to the eardrum,

which separates the outer ear from the

middle ear. The eardrum vibrates when

sound hits it. It then passes the vibrations

to the middle ear.

The middle ear is an air-filled space. It is

about 0.75 inch (1.9 centimeters) high

and 0.20 inch (0.5 centimeter) wide.

Inside this space are three small bones.

These bones work together to send

vibrations along to the inner ear.

The inner ear is filled with fluid. It contains

the main organ of hearing, a coiled

tube called the cochlea. The vibrations

make waves in the fluid of the cochlea.

These waves produce the sound signals

that are sent to the brain. The inner ear

also has structures called the semicircular

canals, which help to keep the body in

balance.

Problems with the Ear

When people fly, drive in the mountains,

or swim deep underwater, their

ears may “pop.” This painful or stuffy

feeling usually goes away on its own.

Infections of the middle ear are a common

problem in children. They often

develop after a cold. Ear infections can

be quite painful, but they are usually not

serious. Serious problems with the inner

ear can lead to deafness.

Ears of Other Animals

Ears are much more important to mammals

than to other groups of animals.

Only mammals have the outside ear

parts called auricles. The ears of different

mammals work basically the same way

that human ears do. However, many

The three main parts of the human ear are

the outer, the middle, and the inner ear.

The huge auricles (outside ear parts) of a

bat help it to tell from which direction a

sound is coming.

BRITANNICA STUDENT ENCYCLOPEDIA Ear 87

mammals can move their auricles to

pick up sound coming from any direction.

Other groups of animals have only

some ear parts. Birds have an ear canal,

a middle ear, and an inner ear. Their

hearing is similar to that of humans.

Most amphibians and reptiles have

middle ears and inner ears with one

bone. The eardrums of frogs and some

reptiles are visible on the sides of the

head. Snakes lack outer and middle

ears. The snake’s skull bones pass

vibrations to the inner ear. Some fish

have a simple inner ear buried deep in

the head. Insects and spiders also lack

ears, but they can sense vibrations in

other ways.

#More to explore

Deafness • Sound

Earhart, Amelia

Amelia Earhart was a pioneer of aviation.

She was the first woman to fly

alone across the Atlantic Ocean. She

disappeared during a flight in 1937 and

was never found.

Amelia Mary Earhart was born on July

24, 1897, in Atchison, Kansas. Her family

did not want her to be a pilot, but

she learned anyway.

In 1928 Earhart became the first woman

to fly across the Atlantic. She was a passenger

in an airplane that someone else

piloted. Four years later she became the

first woman—and only the second

person—to fly across the Atlantic alone.

She flew from the island of Newfoundland

to Ireland. Her flight lasted 14

hours and 56 minutes.

Earhart next made a series of flights

across the United States. She wanted to

get more women involved in aviation.

She also wanted to make flying more

popular as a way to travel. For a time

Earhart worked for one of the first regular

passenger services to fly between

New York City andWashington, D.C.

In June 1937 Earhart set out from

Miami, Florida, to fly around the world.

She took along a navigator, Fred

Noonan, to help her find the way. On

July 2 their plane vanished over the

Pacific Ocean. The U.S. Army and Navy

and the Japanese navy sent out searchers.

However, no one ever found the two

fliers or their plane.

In January

1935 Earhart

made a solo

flight from

Hawaii to

California.

She was the

first pilot to

succeed on the

dangerous

route.

Amelia Earhart

88 Earhart, Amelia BRITANNICA STUDENT ENCYCLOPEDIA

Earth

Earth is one of the eight planets that

orbit, or travel around, the sun in the

solar system. It is the third planet from

the sun. Earth travels around the sun at

an average distance of about 93 million

miles (150 million kilometers). It

appears bright and bluish when seen

from outer space.

Earth is the only planet in the solar system

that can support life. Life is possible

on Earth because the planet has water

on its surface and oxygen gas in its air.

Earth also has the perfect range of temperatures

for life. It is not too hot, like

Venus, and not too cold, like Neptune.

The average temperature on Earth is

about 60° F (16° C).

Physical Features

Earth is the fifth largest planet in the

solar system. It is made up of three layers:

the core, the mantle, and the crust.

The core is the center of the planet. It is

about 4,300 miles (6,900 kilometers)

across. The core is very hot. The mantle

covers the core. It is about 1,800 miles

(2,900 kilometers) thick. The crust is

Earth’s thin, rocky outer layer. At its

thickest the crust is about 19 miles (31

kilometers) thick. Plants, animals, and

people live on the crust.

Land covers about 30 percent of Earth’s

surface. The land is divided into seven

huge pieces called continents. These

continents are Africa, Antarctica, Asia,

Australia, Europe, North America, and

South America.

Water covers about 70 percent of Earth’s

surface. This water is in the form of

oceans, rivers, lakes, and groundwater.

The four major water bodies on Earth

are the Arctic, Atlantic, Pacific, and

Indian oceans. They surround the continents.

Some water is frozen. For

example, there are large ice sheets in the

Arctic and Antarctic regions.

The layer of gases surrounding Earth is

called the atmosphere. This is the air

that living things breathe. Earth’s atmosphere

goes up to a few hundred miles

above the surface. The atmosphere gets

thinner as it gets farther from the surface.

It contains mostly water vapor and

the gases nitrogen (77 percent) and oxygen

(21 percent).

The three layers of Earth are the core, the

mantle, and the crust. The crust is the thinnest

layer.

BRITANNICA STUDENT ENCYCLOPEDIA Earth 89

Orbit and Spin

Like all planets, Earth has two types of

motion: orbit and spin. Its orbit is the

path it takes around the sun. It takes

Earth 365.25 days to go around the sun

once. This is equal to one calendar year.

The force that keeps Earth orbiting the

sun is called gravity.

Earth also spins, or rotates around its

axis. The axis is an imaginary line that

runs through Earth’s center from the

North Pole to the South Pole. Earth

completes one rotation in 24 hours.

This is equal to one day.

Seasons

Earth’s axis does not run straight up and

down in relation to the sun. Instead it is

tilted slightly. As Earth moves around

the sun, the North Pole is tilted toward

the sun for about half the year. During

this time the northern half of the planet,

called the Northern Hemisphere, gets

more sunlight than the southern half, or

the Southern Hemisphere. During the

other half of the year the North Pole is

tilted away from the sun. Then the

Southern Hemisphere gets more sun

than the Northern Hemisphere.

These differences in how sunlight hits

different parts of Earth cause the seasons.

For example, the Northern Hemisphere

has its warmest season, summer,

when it is tipped closer to the sun. At

the same time the Southern Hemisphere

has winter, its coldest season.

Satellite

Earth has one natural satellite called the

Moon. A satellite is an object in space

that orbits another object of a larger size.

The Moon is about 239,000 miles

(384,000 kilometers) from Earth.

Earth Through Time

Scientists believe that Earth is about 4.6

billion years old. Earth’s surface has

changed greatly since it was first formed.

Some changes have taken place over

millions of years as wind and water have

eroded, or worn away, the land. Erosion

has created features such as the Grand

Canyon. Other changes have happened

very quickly. The force of an erupting

volcano or an earthquake can change the

surrounding land in just hours.

The scientists who study these changes

are called geologists. They have divided

Earth’s history into time periods called

eons and eras. They use these periods to

explain how and when changes on Earth

took place. For instance, geologists have

found that the Atlantic Ocean was

As seen from outer space, Earth looks like a

bright blue ball with swirling white clouds.

Earth is the

only planet of

the solar

system whose

name does not

come from

Greek or

Roman

mythology.

90 Earth BRITANNICA STUDENT ENCYCLOPEDIA

formed during the Mesozoic era, a division

of the Phanerozoic eon.

#More to explore

Atmosphere • Continent • Earthquake

• Erosion • Geology • Gravity

• Hemisphere • Moon • Planets • Season

• Solar System • Volcano

Earth Day

Every April 22, people celebrate Earth

Day to show how much they care about

the planet. Many people use the day to

do projects that will help Earth. Some

meet to discuss how to limit pollution

and how to save endangered animals and

plants. Others plant trees, clean up parks

and beaches, or set up recycling stations.

In some places concerts and organized

walks raise money for environmental

groups.

Gaylord Nelson, a U.S. senator, founded

Earth Day. He asked Denis Hayes, a

college student, to organize the first

Earth Day events. About 20 million

Americans celebrated the first Earth Day

in 1970. The day made more Americans

aware of the damage that people had

done to the environment. In 1990

Hayes organized the first International

Earth Day. About 200 million people in

141 countries took part.

#More to explore

Pollution • Recycling

Earthquake

In an earthquake, huge masses of rock

move beneath Earth’s surface and cause

the ground to shake. Earthquakes occur

constantly around the world. Often they

are too small for people to feel at all.

Sometimes, however, earthquakes cause

great losses of life and property.

Causes

Most earthquakes are caused by changes

in Earth’s outermost shell, or crust. The

crust is not a solid mass. Instead it is

made up of about a dozen rock masses

called plates that are constantly moving.

In different places they move apart, collide,

or slide past each other. Over time

this movement causes great pressure to

build up. When the pressure becomes

too great, the rock masses suddenly shift

along a crack in the crust, called a fault.

The shifting rocks release energy in the

form of shock waves. The waves spread

through the rock in all directions, causing

an earthquake. In the most powerful

quakes, people thousands of miles away

Volunteers clear overgrowth from a hill in

an Earth Day clean-up effort.

The San

Andreas Fault

in southern

California is

about 650

miles (1,050

kilometers)

long. It can

easily be seen

from above

the ground.

BRITANNICA STUDENT ENCYCLOPEDIA Earthquake 91

from the center of the quake can feel the

ground shake.

A small number of earthquakes have

other natural or human causes. The

movement of molten rock beneath a

volcano can trigger an earthquake. The

pressure resulting from holding vast

amounts of water behind large dams can

cause minor quakes. So can underground

nuclear explosions and the digging

of mines.

Effects

An earthquake may be powerful enough

to change the surface of Earth, thrusting

up cliffs and opening huge cracks in the

ground. Earthquakes can do great damage

to buildings, bridges, railroads, and

other structures. The violent shaking

during earthquakes often causes other

Earth movements, such as avalanches.

Some quakes happen in or near oceans.

These quakes can cause huge, destructive

waves called tsunamis to sweep

ashore.

Where Earthquakes Occur

Most earthquakes take place along the

boundaries of Earth’s crustal plates. One

great earthquake belt circles the Pacific

Ocean along the mountainous west

coasts of North and South America and

runs through the island areas of Asia. It

is known as the ring of fire. The famous

San Andreas Fault of California is part

of this belt.

A second, less-active belt is between

Europe and North Africa in the Mediterranean

region and includes portions

of Asia. A small number of quakes occur

in the interior of plates rather than along

the edges.

In an earthquake, the ground can move up

and down. It can also move sideways.

An earthquake in Japan was

powerful enough to destroy an

elevated expressway.

92 Earthquake BRITANNICA STUDENT ENCYCLOPEDIA

Measuring Earthquakes

Scientists record the shock waves produced

in an earthquake with an instrument

called a seismograph. They

measure the strength of a quake in different

ways. The Richter scale measures

earthquakes based on the amount of

energy they release. The weakest earthquakes

are close to zero on the scale; the

strongest measure about 9. The Mercalli

scale measures the amount of destruction

caused by an earthquake on a scale

of 1 to 12.

#More to explore

Avalanche • Earth • Energy • Plate

Tectonics • Ring of Fire • Tsunami

• Volcano

Easter

Easter is the holiest day of the year for

Christians. It celebrates their belief in

the resurrection, or the rising from the

dead, of Jesus Christ. Jesus was the

founder of the religion of Christianity.

Easter is always observed on a Sunday in

the Spring, but its date varies.

The week before Easter Sunday is

known as HolyWeek. During this week,

Christians remember the events they

believe took place at the time of Jesus’

death. Palm Sunday recalls the entrance

of Jesus into Jerusalem shortly before his

death. Holy Thursday marks the Last

Supper of Jesus with his disciples, or

followers. Good Friday remembers the

crucifixion, when Jesus was killed by

being nailed to a cross. Christians

believe that Jesus was resurrected on the

third day after his death. Easter is therefore

a celebration of new life.

On Easter, Christians attend special

church services. A number of popular

folk customs are also associated with

Easter. These have to do with rabbits

and colored eggs, which are ancient

symbols of new life. In some countries

children color eggs and then the eggs are

hidden for them to find. According to

tradition the Easter Bunny also leaves

eggs and candy for children on Easter

morning.

#More to explore

Christianity

Eastern

Orthodox

Churches

Eastern Orthodoxy is one of the main

branches of Christianity. Eastern Orthodoxy

consists of a group of churches,

Christians attend an Easter service at sunrise

near the Grand Canyon in Arizona.

BRITANNICA STUDENT ENCYCLOPEDIA Eastern Orthodox Churches 93

most of which are associated with a particular

country. The patriarch, or leader,

of Constantinople (present-day Istanbul,

Turkey) is the general representative of

Eastern Orthodoxy. But each church is

independent and selects its own head.

There are more than 200 million Orthodox

Christians in all.

Beliefs and Practices

The Orthodox Christians trace their

history back to the beginnings of Christianity.

They believe that they follow

Christianity in the same way that the

first Christians did. Unlike Roman

Catholics, they do not recognize the

authority of the pope.

Every Sunday, Orthodox churches celebrate

their most important service, the

Divine Liturgy. During the service,

church members eat bread in memory of

Jesus’ Last Supper. As in other Christian

churches, this is known as Communion.

It is one of the seven sacraments, or holy

ceremonies, of the Orthodox church.

History

Christianity became the official religion

of the Roman Empire in the AD 300s. In

the 400s the western part of the empire

fell to invaders. But the eastern part

survived for another 1,000 years as the

Byzantine Empire. The pope emerged as

the leader of theWestern church, and

the patriarch of Constantinople became

the head of the Eastern church.

The Eastern andWestern churches disagreed

on several issues. They grew apart

over several centuries and finally officially

separated in 1054. They came to

be called the Eastern Orthodox churches

and the Roman Catholic church.

Muslim Turks conquered the last part of

the Byzantine Empire in 1453. The

Russian church, which was outside the

empire, was the only Orthodox church

that remained free of Turkish rule. It

thus took a leadership role among the

Orthodox churches.

#More to explore

Byzantine Empire • Christianity • Jesus

Christ • Roman Catholicism • Rome,

Ancient

East Indies

The East Indies is the world’s largest

island group. It is sometimes known as

the Malay Archipelago. The East Indies

includes the Moluccas, which were once

fabled as the Spice Islands.

The islands extend for more than 3,800

miles (6,100 kilometers). They lie

between the Asian mainland in the

Some Eastern Orthodox churches have

onion-shaped domes.

94 East Indies BRITANNICA STUDENT ENCYCLOPEDIA

north and west and Australia to the

south. The term East Indies has been

used at different times to refer to different

sections of these islands. In a general

sense the term East Indies includes all of

the islands in the area, as well as all of

mainland Southeast Asia and India.

More specifically, the group consists of

the more than 13,000 islands that make

up Indonesia, parts of Malaysia, Brunei,

and Papua New Guinea. The islands of

the Philippines are also sometimes

included in the East Indies.

The East Indies were famous for their

spices at least 4,000 years ago. For many

years spices were considered very valuable.

People traveled far to buy and sell

them, and important cities started as

trading centers. Europeans looking for

new routes to the East Indies discovered

the lands of the Americas. For centuries

European powers also fought over the

riches of the East Indies. They took control

of much of the area and established

colonies there. No European colonies

remain in the East Indies today, however.

#More to explore

Brunei • Indonesia • Malaysia • Papua

New Guinea • Philippines

On an island in the East Indies, baskets of garlic and spices are ready for sale at a market.

The islands have long been known for their spices.

BRITANNICA STUDENT ENCYCLOPEDIA East Indies 95

East Timor

East Timor is one of the world’s newest

countries. Its capital is Dili.

Geography

East Timor covers the eastern half of the

island of Timor in Southeast Asia. The

western half is part of Indonesia. East

Timor also includes an area called

Ambeno (on the northwestern coast of

Timor) and two small islands.

East Timor is mountainous and dry.

Sandalwood trees grow in hilly areas.

Shrubs, grass, coconut palms, and eucalyptus

trees grow in the lowlands.Wildlife

includes monkeys, deer, civet cats,

snakes, and crocodiles.

People

Most of the people of East Timor have

Southeast Asian or South Pacific roots.

Christianity is the chief religion. The

major languages are Tetum, Portuguese,

Indonesian, and English.

Economy

Most of the people of East Timor work

as farmers. Important crops include

corn, rice, cassava, sweet potatoes, and

coconuts. The country also produces

coffee, livestock, and clothing. Supplies

of oil and natural gas lie offshore.

History

Little is known of Timor’s early history.

The Portuguese settled on the island in

1520. The Dutch also claimed part of

the island, and the two countries fought

for control for many years. Portugal

gained firm control over East Timor by

1914. In 1975 East Timor declared its

independence. However, Indonesia soon

invaded.

In 1999 Indonesia allowed East Timor

to vote for or against independence. The

voters chose independence, but armed

groups that opposed it killed hundreds

and left the country in ruins. The

United Nations stepped in to keep peace

as East Timor set up a government. In

2002 East Timor became an independent

republic.

..More to explore

Dili • Indonesia

East Timorese girls perform a traditional

dance in Manatuto, East Timor.

Facts About

EAST TIMOR

Population

(2008 estimate)

1,078,000

Area

5,639 sq mi

(14,604 sq km)

Capital

Dili

Form of

government

Republic

Major cities

Dili, Dare, Baucau,

Maliana,

Ermera

96 East Timor BRITANNICA STUDENT ENCYCLOPEDIA

Echidna

Echidnas are unusual mammals. Along

with their relative the platypus, echidnas

are the only living mammals that lay

eggs. Echidnas are also called spiny anteaters.

There are three species, or kinds, of

echidna. The short-nosed echidna is

common in Australia and on the island

of Tasmania. Two species of long-nosed

echidna live only on the island of New

Guinea.

Echidnas are stocky animals with a short

tail. They have brownish fur with spines

sticking through. Their feet have strong

claws that are good for digging. They

have a very small mouth and a long,

sticky tongue. The short-nosed echidna

is about 12 to 18 inches (30 to 45 centimeters)

long. It has a straight snout that

points forward. The long-nosed echidnas

are usually 18–31 inches (45–78

centimeters) long. They have a longer,

downward-pointing snout.

The short-nosed echidna eats ants and

termites that it catches with its long,

sticky tongue. Long-nosed echidnas eat

mostly earthworms.

A female echidna usually lays a single

leathery egg. The mother holds the egg

in a pouch on her body. It hatches about

10 days later. The newborn lives in the

pouch for about two months. The baby

sucks milk through special hairs on the

mother’s body. The young echidna goes

off on its own after it has grown spines

and fur and can find its own food.

#More to explore

Anteater • Mammal • Platypus

Eclipse

An eclipse happens when one object in

space blocks another from view. For

example, during a solar eclipse theMoon

comes between Earth and the sun. The

Moon blocks the sun for a time so that

people on Earth cannot see it.

In ancient times solar eclipses caused

great fear and wonder. People did not

understand why the sky sometimes

darkened in the middle of the day.

Today scientists understand why eclipses

happen and can determine when they

will occur.

Eclipses happen because planets, moons,

and other objects constantly move

through space. For instance, Earth travels

around the sun in a path called an

The short-nosed echidna is a common

mammal in Australia.

BRITANNICA STUDENT ENCYCLOPEDIA Eclipse 97

in the middle. The Moon is then in

Earth’s shadow. But the Moon does not

appear completely dark. Instead, it glows

a dim orange or red color. This is

because some light reaches the Moon

indirectly. This light bounces off the

gases surrounding Earth and then hits

the Moon.

Lunar eclipses can be total or partial.

Unlike a solar eclipse, a lunar eclipse is

safe to view directly.

#More to explore

Earth • Moon • Sun

Ecology

Ecology is the study of the relationships

between living things and their surroundings,

or environment. Scientists

who work in ecology are called ecologists.

Ecologists examine how living

things depend on one another for survival.

They also study how living things

use such natural resources as air, soil,

and water to stay alive.

Some ecologists work in laboratories.

Laboratory experiments allow ecologists

to study things under controlled conditions.

For instance, they can experiment

to see how plants react to different

amounts of light or water. Such studies

are harder in a natural setting because

weather and other natural conditions

cannot be controlled.

However, many ecologists do work in

natural, outdoor settings. They look at

all the different factors that affect ecosystems,

or communities of living things.

Studies in the outdoors are useful

because they show what is actually happening

in the environment.

Ecology is important because it shows

how changes in the environment affect

the survival of living things. For

example, when pollution kills certain

living things, the animals that feed on

them also may die. The work of ecologists

has convinced many people to protect

the environment and all the

ecosystems that it supports.

#More to explore

Ecosystem • Environment • Living

Thing

Economics

Economics is the study of the economy,

or the part of a society that creates

wealth.Wealth is not just money.

Wealth comes from the production of

goods and services, which people buy

with money. People who study economics,

called economists, look at how

An ecologist studies pitcher plants as they

grow in a nature preserve in North Carolina.

BRITANNICA STUDENT ENCYCLOPEDIA Economics 99

people create wealth, how they use it,

and how different people get different

amounts of it.

Parts of an Economy

A society creates wealth by producing

goods and services. Goods include such

objects as apples, cars, and roads. Services

are things that people do for others,

such as gymnastics lessons, banking,

and dental care. People who buy these

goods and services are called consumers.

The process of creating the goods and

services is called production. There are

three major factors in production. The

first is land. Land can mean a large farm

or a tiny workshop. Land also includes

natural resources like oil and minerals.

The second factor of production is

labor, or people who work for pay.

Workers may be rewarded with wages,

or—if they own the business—with

profits. (Profits are the money that a

business keeps after paying costs.) The

third factor of production is capital.

This includes the tools, factories, and

offices that are used to make the goods

and services.

All the companies producing a particular

kind of product or service are grouped

together in what is known as an industry.

Industries that make things are

called manufacturing industries. Industries

that sell services are called service

industries.

Branches of Economics

There are several different branches of

economics. The study of individual consumers

and businesses is called microeconomics.

The study of how a whole

country’s economy works is called macroeconomics.

Microeconomics

Economists who study microeconomics

look at how consumers spend their

money. They try to explain why consumers

buy one product rather than

another. They also look at why companies

choose to produce one good or service

rather than another.

The amount consumers want to buy is

called demand. The amount companies

produce is called supply. Price strongly

affects supply and demand. If a manufacturer

charges a high price for a product,

usually it will sell few products. If it

reduces the price, usually it will sell

more products.

Macroeconomics

Economists who study macroeconomics

look at the value of all the goods and

The economics of supply and demand sets

the prices in a village market.

100 Economics BRITANNICA STUDENT ENCYCLOPEDIA

services that a country produces. In this

way, they measure a whole country’s

wealth.

Governments are interested in macroeconomics,

too. A government plays an

important role in its country’s economy.

When a government decides which

goods and services should be produced

and sold, the economy is said to be

planned. Countries with socialist or

Communist governments usually have

planned economies.

By contrast, when a government lets

companies and consumers decide what

will be produced, the economy is called

a free market. Countries with capitalist

governments have free-market economies.

But even capitalist governments

affect the economy. They do this by

raising or lowering taxes and changing

the amount banks can charge for loans.

These actions cause people to have more

or less money to spend on goods and

services.

#More to explore

Capitalism • Communism • Industry

• Manufacturing • Money • Socialism

Ecosystem

An ecosystem is a group of plants, animals,

and other living things that live in

the same surroundings. An ecosystem

also includes nonliving materials—for

example, water, rocks, soil, and sand. A

swamp, a prairie, an ocean, and a forest

are examples of ecosystems.

Each living thing in an ecosystem has a

role to play—as a producer, a consumer,

or a decomposer. Green plants are producers.

They make their own food

through a process called photosynthesis.

Animals, including humans, are consumers.

They eat, or consume, plants or

other animals. Bacteria and other living

things that cause decay are decomposers.

They break down the waste products

and dead tissue of plants and animals.

They return nutrients to the soil. The

way that producers, consumers, and

decomposers provide nutrients for one

another is called a food chain.

An ecosystem’s health depends on a

delicate balance among all its members

and the environment. If something disturbs

the balance, the ecosystem and all

its members may suffer. Natural things

such as a changing climate can disturb

ecosystems, as can human activities such

as polluting.

#More to explore

Environment • Food Chain • Living

Thing

A swan builds a nest in a wetland ecosystem

in England.

BRITANNICA STUDENT ENCYCLOPEDIA Ecosystem 101

Ecuador

Ecuador gets its name from the equator,

which passes through the northern part

of the country. Located in northwestern

South America, Ecuador straddles part

of the Andes Mountains and occupies

part of the Amazon River basin. The

capital city, Quito, stands on the lower

slopes of an old volcano.

Geography

Ecuador is bordered by Colombia, Peru,

and the Pacific Ocean. Its territory

includes the Galapagos Islands, which lie

to the west.

Along the coast the land is flat, with

tropical rain forest in the north and

desert in the south. Two ranges of the

Andes Mountains run from north to

south through central Ecuador. The

highest peak is Chimborazo, at 20,702

feet (6,310 meters). Between the ranges

are fertile valleys and plateaus. East of

the Andes, rain forests grow in the basin

of the Amazon River. In this region the

Napo River flows toward Peru.

Most of Ecuador has a hot, humid climate

year-round. The mountain regions

are cooler, and the highest peaks are

snowcapped.

Plants and Animals

Palms grow in the central part of Ecuador’s

coast. The coastal region is also the

agricultural center of the country. The

mountains have some evergreen forests

as well as grasses at higher elevations.

Logging has threatened many of Ecuador’s

rain forests.

In the rain forests live monkeys, jaguars,

ocelots, foxes, weasels, otters, skunks,

raccoons, coatis (relatives of the raccoon),

and tree-dwelling mammals

called kinkajous. The Galapagos Islands

are known for their unusual animal life,

including giant tortoises and marine

iguanas.

People

More than 40 percent of Ecuadorans are

mestizos—people with mixed European

and American Indian roots. Almost the

same number of people are American

Indians. Whites, blacks, and Asians form

smaller groups. Most people are Roman

Catholics. Spanish is the official language,

but many Indians speak Quechua

or Shuar.

Most Ecuadorans live in cities along the

coast or in the mountains. Very few

102 Ecuador BRITANNICA STUDENT ENCYCLOPEDIA

people live in the eastern part of the

country.

Economy

Ecuador’s economy depends on natural

resources and agriculture. The country

produces mainly oil, bananas, and

shrimp. Other important products

include sugarcane, palm oil, rice, corn,

cut flowers, and canned fish. In recent

years manufacturing has increased in

Ecuador. Factories make tires, textiles,

and other items.

History

The land now known as Ecuador had a

long history before the arrival of Europeans.

People there made pottery figures

as early as 3000 to 2500 BC. In the AD

1400s the Inca of what is now Peru conquered

the area. They ruled until Spain

invaded in 1534. The Spanish built

huge estates and forced the Indians to

work on them.

With help from Simon Bolivar, Ecuador

won its independence from Spain in

1822. It joined Colombia and Venezuela

to form the Republic of Colombia,

called Gran Colombia. Bolivar served as

its president. Ecuador left the republic

in 1830 and became an independent

country.

Since independence Ecuador has had

many changes of government. Because

of the constant change, it has been difficult

for Ecuadorans to make progress.

However, Ecuador solved one longstanding

problem in 1998, when the

president signed a peace treaty with

Peru. The two countries had been fighting

for many years over part of their

shared border.

..More to explore

Andes • Bolivar, Simon • Galapagos

Islands • Quito

Women sell reeds at a market in Ecuador.

The reeds are used to make hats.

Cotopaxi is an active volcano in the Andes Mountains of Ecuador.

Facts About

ECUADOR

Population

(2008 estimate)

13,481,000

Area

105,037 sq mi

(272,045 sq km)

Capital

Quito

Form of

government

Republic

Major cities

Guayaquil,

Quito, Cuenca,

Machala, Santo

Domingo de los

Colorados,

Manta

BRITANNICA STUDENT ENCYCLOPEDIA Ecuador 103

Edinburgh

Population

(2006 estimate)

464,000

Edinburgh is the capital of Scotland,

one of the four main parts of the country

called the United Kingdom. The city

is known as a place of learning. Through

the years it has produced many great

thinkers and writers.

Cityscape

Edinburgh is built on a series of hills

and rocky ridges. It has a port on a part

of the North Sea.

The oldest section of Edinburgh is

called the Old Town. It developed

around Castle Rock, which rises high

above a valley floor. At its top stands

Edinburgh Castle, the home of Scottish

kings and queens in ancient times.

Edinburgh’s other main section is the

New Town. Despite its name, it is more

than 200 years old. Today it is the city’s

main business area.

Economy

Edinburgh is a major center of banking

and law. Other services, such as education,

health care, trade, and tourism, are

also important.

History

People have lived in the Edinburgh

region for thousands of years. What is

now called the Old Town dates back to

the 1000s.

Edinburgh became Scotland’s capital in

the 1400s. Scotland was then an independent

kingdom. It became part of the

United Kingdom in 1707.

In the 1700s Edinburgh became a great

cultural center. Many important philosophers,

writers, and scientists lived

there. It was also the birthplace of the

Encyclop.dia Britannica.

Edinburgh’s New Town was built in the

late 1700s and early 1800s. The city

grew greatly over the next century.

Scotland began to govern most of its

own affairs again in 1999. Scottish law-

Edinburgh Castle is one of Scotland’s most

popular tourist attractions.

104 Edinburgh BRITANNICA STUDENT ENCYCLOPEDIA

makers began meeting in Edinburgh

once more.

#More to explore

Scotland • United Kingdom

Edison, Thomas

Alva

Thomas Edison was called a “wizard”

because of his many important inventions.

He created more than 1,000

devices on his own or with others. His

best-known inventions include the phonograph

(record player), the lightbulb,

and motion-picture equipment.

Thomas Alva Edison was born on February

11, 1847, in Milan, Ohio. He

experienced hearing loss at an early age.

He was an imaginative and curious

child. He did poorly in school, though,

perhaps because he could not hear his

teacher. His mother then educated him

at home.

When Thomas was a teenager he

became a telegraph operator. Telegraphy

was one of the nation’s most important

communication systems at the time.

Thomas was good at sending and taking

messages in Morse code. He loved tinkering

with telegraphic instruments, and

he developed several improvements for

them. By early 1869 he had quit his

telegraphy job to become a full-time

inventor.

Edison built research laboratories at

Menlo Park andWest Orange, New

Jersey. He later created companies that

produced and sold his successful inventions.

Although most of his life was devoted to

his work, Edison’s family was also

important to him. He married twice and

had six children. Edison died on October

18, 1931.

#More to explore

Telecommunication • Telegraph

Education

Education is the process of gathering

information about the world and oneself.

Formal education is learning that

takes place in schools or with private

teachers. People also learn from their

families, with friends, while traveling,

and in many other places. This is called

informal education.

Edison also

worked to

develop the

electric power

systems that

bring electricity

into homes

and businesses.

Thomas Edison poses with a phonograph

that recorded sound on sheets of tinfoil.

BRITANNICA STUDENT ENCYCLOPEDIA Education 105

Formal Education

Many children around the world go to

free, public schools. Others go to private

schools, which charge tuition, or fees.

Some study at home with parents, which

is called home schooling. Some have

tutors, or private teachers.

Different countries provide different

levels of formal education. In the United

States formal education starts with preschool

and kindergarten. At about age 6,

children begin primary school, which is

also called grade school or elementary

school. Some communities have middle

schools or junior high schools for students

between 11 and 14 years old.

High school, or secondary school, lasts

from about age 14 until about age 18.

Many students continue their education

after high school. Some attend trade

schools or community colleges. Others

go to state colleges and universities.

Some go to private colleges and

universities.

Adults who have finished their formal

education can continue their education

at night or on weekends. The courses

they take are known as continuing education

or adult education classes.

History

In the earliest times children got their

education directly from parents and

other adults. They learned mainly skills

for survival.

Eventually people established cities and

advanced civilization. As societies developed

they set up schools to teach reading,

writing, arithmetic, and other

subjects.

The first schools were usually just for

boys. Most of the students came from

rich and powerful families. Often the

purpose of their education was religious

training.

Some schools had other purposes as

well. Many schools focused on military

training. Sometimes youths attended

special schools to learn the art of public

speaking. These skills were meant to

help them become future leaders.

Most girls received their education at

home. They learned cooking, sewing,

and other useful skills.

Over time education became available

to more people, not just the rich and

powerful. The governments of some

countries set up public systems of

education in the 1800s. More schools

opened to girls.

Education gives students the answers to

many questions.

106 Education BRITANNICA STUDENT ENCYCLOPEDIA

In the United States many early schools

had only a single room and one teacher.

Children of every age learned together.

In 1751 Benjamin Franklin founded a

secondary school—the first of many.

Students studied such subjects as

history, mathematics, and navigation. In

the 1800s free elementary and

secondary schools opened across the

United States.

During the 1900s, as education became

more important, teachers colleges

opened. The requirements for becoming

a teacher became stricter. Teaching

became a highly respected profession.

#More to explore

Arithmetic •Writing

Eel

Eels are fishes that look like snakes.

There are hundreds of different species,

or types, of eel. They belong to a large

group of fishes called the eel order.

Where Eels Live

Many species of eel live in warm, salty

seas and oceans. Morays and congers are

two well-known types of marine, or sea,

eel. Freshwater eels live in rivers, lakes,

and ponds on almost every continent.

They travel to saltwater to reproduce.

Physical Features

Adult eels range in length from 4

inches (10 centimeters) to 11.5 feet

(3.5 meters) long. An eel has a pointed

head, sometimes with a wide mouth

and sharp teeth. A fin runs along the

back and around the tip of the tail. The

body is usually smooth. Deep-sea eels

are often black or gray. Eels that live in

tropical reefs may have bright colors

and patterns.

The American and European eels live in

freshwater. Congers are marine, or sea, eels.

An African student uses a

pointer and blackboard.

BRITANNICA STUDENT ENCYCLOPEDIA Eel 107

Behavior

Many species of eel hide in mud or

among rocks during the day. They come

out at night to hunt for food. Eels eat

shrimps, snails, fishes, mussels, and

worms.

Eels generally live alone. But garden eels

live in colonies of hundreds of eels. Each

garden eel hides in a tube that it digs in

the sandy ocean floor.

Eels breathe through gills, as other fishes

do. But freshwater eels also can absorb

oxygen through their skin. This allows

them to move across land.

Life Cycle

Baby eels, or larvae, hatch from eggs in

the ocean. The larvae are typically flat

and transparent. After a period of

growth, they go through metamorphosis.

This is a series of changes that turn

the larvae into young eels, or elvers. Elvers

look like miniature adult eels.

After the elvers reach adulthood, they

are ready to mate. Most species migrate,

or travel, to a particular area to mate and

lay eggs.

#More to explore

Fish • Metamorphosis

Egg

The young of most animals grow from

eggs. Only female animals make eggs.

Male animals make cells called sperm. A

sperm must join an egg before the egg

can grow into a new animal.

In most mammals, the egg is just a cell,

called an ovum, inside the mother’s

body. A sperm cell joins with the egg cell

in a process called fertilization. The fertilized

egg grows and develops inside the

mother until the baby is ready to be

born. Most other female animals lay

eggs, or release them outside their body

to develop.

Eggs need protection while the young

develop inside them. Fish eggs often

float in a protective jelly. Bird and reptile

eggs have an outer shell. In bird eggs the

shell is hard; in reptile eggs it is tough

and elastic. Eggs with shells contain an

egg cell and food, called yolk, for the

developing young, called an embryo.

Many animals, including humans, eat

the eggs of other animals. Fish eggs,

called roe or caviar, are common in

Japanese food. People around the world

eat bird eggs, especially those of chickens

and ducks.

Scientists consider

the fish

called electric

eels to be different

from

true eels. Electric

eels live in

South American

waters.

Some insects, such as ladybugs, lay their

eggs on plant leaves or stems.

108 Egg BRITANNICA STUDENT ENCYCLOPEDIA

Egypt

The Arab Republic of Egypt is a country

in the northeastern corner of Africa.

Ancient Egypt was one of the earliest

and most important civilizations in the

world. The modern country plays a key

role in Middle Eastern politics. Egypt’s

capital is Cairo.

Geography

Egypt shares borders with Libya, Sudan,

Israel, and the Palestinian territory of

the Gaza Strip. Egypt’s northern coast is

on the Mediterranean Sea, and its eastern

coast is on the Red Sea. The Nile

River flows northward into the Mediterranean.

It fans out into the Nile delta, a

triangular area at the mouth of the river.

The Nile divides Egypt into theWestern

Desert and the Eastern Desert. The

Western Desert is low-lying and generally

flat. The Eastern Desert has rolling

hills and mountains in the southeast. To

the northeast is the Sinai Peninsula, the

only land bridge between Africa and

Asia. The Suez Canal separates Sinai

from the rest of Egypt.

Egypt has only two real seasons: a cool,

mild winter and a hot summer. The

climate is very dry and sunny.

Plants and Animals

TheWestern Desert has very few plants.

The Eastern Desert and Sinai have

thorny shrubs, small desert plants, and

herbs. The acacia is one of the few native

trees. Around the Nile are date palms

and many water plants, including reeds

and grasses.

Egypt’s wild animals include mountain

sheep and goats, gazelles, miniature

desert foxes, hares, jackals, and mongooses.

Rodents, insects, lizards, and

snakes are also common. Many types of

birds live in Egypt year-round or pass

through on their migrations.

People

Most Egyptians are descendants of the

Hamites of ancient Egypt and of the

Arabs who migrated to Egypt centuries

ago. Other groups include Nubians,

Roma (Gypsies), Armenians, and

Greeks. Arabic is the official language,

and Islam is the official religion. About

15 percent of Egyptians are Christians,

mostly members of the Coptic Orthodox

Church. Egypt also has a small Jewish

community. Almost all Egyptians

BRITANNICA STUDENT ENCYCLOPEDIA Egypt 109

live in the Nile valley and delta. More

than half of the people live in rural

areas.

Economy

Mining and manufacturing are important

parts of Egypt’s economy. The

country mines petroleum (oil) and natural

gas. It produces valuable crude oil,

cotton goods, processed foods, chemicals,

iron, and steel.

About one fourth of workers are farmers.

Much of Egypt’s farming income

comes from cotton and rice, which it

sells to other countries. Other crops

include sugarcane, corn, tomatoes,

wheat, potatoes, oranges, dates, and

grapes.

Tourism is also very important to the

economy. Visitors come to see the Great

Pyramids at Giza, the Sphinx, and other

monuments of ancient Egypt.

History

Native kings and queens ruled in ancient

Egypt for most of the country’s first

2,500 years, from about 2925 BC until

332 BC. In 332 BC Alexander the Great,

the king of Macedonia, invaded Egypt.

Macedonians ruled Egypt until 30 BC,

when it fell to the Romans. (For more

information about Egypt’s early history,

see Egypt, Ancient.)

Arabs conquered Egypt in AD 642.

Within a few hundred years, Egypt was

transformed into an Arabic state. The

people gradually converted from Christianity

to Islam.

Ottoman Rule and British Control

In 1517 the Turkish Ottoman Empire

took control. Future emperor Napoleon

I of France invaded in 1798, but the

Ottomans soon regained power.

Muhammad !Ali, an officer in the Ottoman

army, became governor of Egypt in

Men ride camels near the three pyramids of

Giza in Egypt.

Muslims kneel in prayer on a

street in Cairo.

110 Egypt BRITANNICA STUDENT ENCYCLOPEDIA

1805. He introduced many reforms in

order to modernize the country. Members

of !Ali’s family governed Egypt for

more than 100 years.

Egypt allowed a French company to

build the Suez Canal in 1859–69. British

troops occupied Egypt in 1882, and

in 1914 the British made Egypt a British

protectorate, or dependent state.

Independence

In 1922 Egypt gained independence. In

the 1940s it helped to found the Arab

League, a union of several Arab countries.

The league became involved in the

growing disputes between Arabs and

Jews in neighboring Palestine. In 1948,

after part of Palestine became the country

of Israel, Egypt and its Arab allies

attacked Israel but were defeated.

A military group overthrew Egypt’s king

in 1952. Gamal Abdel Nasser became

the first native Egyptian ruler in more

than 2,000 years. In 1953 Egypt became

a republic. Nasser wanted Egypt to be a

leader in the Arab world. During this

period tensions increased between Egypt

and Israel.

Anwar el-Sadat became president in

1970. In 1973 Egypt fought another

brief war with Israel, but in 1978 Sadat

met with the Israeli prime minister,

Menachem Begin, in the United States.

The meeting led to a historic peace

treaty between Egypt and Israel in 1979.

Most other Arab countries were

unhappy with the treaty. Muslim radicals

assassinated Sadat in 1981.

Under a new president, Hosni Mubarak,

Egypt’s relations with other Arab countries

improved. Egypt continued to work

for peace in the Middle East.

..More to explore

Cairo • Egypt, Ancient • Middle East

• Nile River • Suez Canal

332 BC 30 BC AD 642 1517 1882 1922 1953

Alexander the

Great invades

Egypt.

Rome takes

control of

Egypt.

Arabs conquer

Egypt.

Egypt becomes

part of the

Ottoman

Empire.

Great Britain

occupies Egypt.

Egypt gains

independence.

Egypt becomes

a republic.

T I M E L I N E

Facts About

EGYPT

Population

(2008 estimate)

74,805,000

Area

385,229 sq mi

(997,739 sq km)

Capital

Cairo

Form of

government

Republic

Major cities

Cairo, Alexandria,

Al-Jizah,

Shubra

al-Khaymah, Port

Said, Suez

BRITANNICA STUDENT ENCYCLOPEDIA Egypt 111

Egypt, Ancient

About 5,000 years ago, the civilization

of ancient Egypt began in the Nile

River valley of northeastern Africa. It

was one of the world’s first civilizations.

It is also one of the most famous

civilizations in history. The ancient

Egyptians built huge pyramids, temples,

palaces, and tombs. Their paintings and

carvings are among the most splendid

ever created. They also produced art

with simple scenes of everyday life,

work, and play that shows many details

of their lives.

Egypt’s dry climate has helped to preserve

many of the things that the ancient

Egyptians made. Archaeologists first

started to uncover the remains of ancient

Egypt in the late 1700s. Through those

remains historians have been able to

learn a great deal about the world of the

ancient Egyptians.

Life in Ancient Egypt

Villages and towns of ancient Egypt

were situated near the Nile River. It was

the chief highway as well as the only

source of water. Very little rain falls in

Egypt. Rain does fall along other parts

of the river, however. Every year the

water from that rain flows downstream

and eventually floods the lands. Afterward,

as the waters flow back, they leave

rich mud behind. The Egyptians planted

wheat and barley in the mud. They grew

other fruits and vegetables using irrigation

(channels of water).

Ancient Egyptian houses were made of

mud bricks. The houses had small windows

and floors of straw matting. Paintings

often decorated the walls.

Many ruins from ancient Egypt can still be

seen today. The temple of Abu Simbel was

built during the reign of Ramses II almost

3,300 years ago. It was dedicated to two

sun gods.

112 Egypt, Ancient BRITANNICA STUDENT ENCYCLOPEDIA

Clothing was simple because the climate

was hot. White linen, woven from the

flax plant, was a common fabric. Men

typically wore a skirt of linen and sometimes

a vest.Women wore a straight,

simple, ankle-length dress.

One of the ancient Egyptians’ finest

achievements was their written

language. The first Egyptian writing

was a system of pictures called

hieroglyphics. The Egyptians were using

hieroglyphics by 3100 BC. The

Egyptians cut or painted the symbols

on the walls of tombs and temples.

Later they developed simpler, curved

forms of writing. The Egyptians used

these forms to write on papyrus, a

paper-like material made from a plant.

The ancient Egyptians worshipped

many gods. The main god of the sun

was Re (or Ra). Each city had its own

special gods. When the city of Thebes

grew in importance, its special god

Amon did also. Eventually the

Egyptians combined Amon with Re.

Amon-Re was considered the king of

the gods.

Osiris, a god of the dead, was another

important god because the Egyptians

believed in life after death.Wealthy

Egyptian families stocked tombs with

items that they thought dead people

would use in the next life.

In addition, the Egyptians used salt and

chemicals to preserve dead bodies as

mummies. They even made mummies

of such animals as cats, ibises, and

crocodiles. Mummies of important

people lay in fancy coffins called sarcophagi.

The coffin of King Tutankhamen

was made of solid gold.

History

Earliest Egypt

People have lived along the banks of the

Nile River for at least 10,000 years. The

narrow valley of the Nile was once

swampy and overgrown with trees,

rushes, and papyrus (a tall, reedlike

plant). The people gradually cleared the

swamps and built villages. They learned

to plant and grow crops. Eventually,

they organized two kingdoms. Upper

Egypt was in the narrow river valley in

the south. Lower Egypt was in the

north, in the broad delta (triangular

piece of land) where the river flows into

the sea.

In about 2900 BC a king named Menes

united the two parts of Egypt. Menes

A tomb from ancient Egypt is painted with

hieroglyphics and many colorful pictures.

The pictures give an idea of what people at

the time looked like and what kind of clothing

they wore.

BRITANNICA STUDENT ENCYCLOPEDIA Egypt, Ancient 113

built the capital city of Memphis. The

site of Memphis is near Cairo, the capital

of modern Egypt.

Old, Middle, and New Kingdoms

After Menes, many kings, called

pharaohs, ruled ancient Egypt. During

the long history there were more than

30 dynasties, or ruling families, of

pharaohs. Historians have grouped

several of these dynasties into three

important periods: the Old Kingdom,

the Middle Kingdom, and the New

Kingdom. These existed from about

2600 to 30 BC.

The Old Kingdom lasted from 2575 to

2130 BC. It was during this period that

the Egyptians built their great pyramids.

Near the great pyramids, the Egyptians

made a huge sculpture called the Great

Sphinx. The Sphinx has the face of a

man and the body of a lion.

After 2130 BC Egypt suffered civil wars.

The country was split up until about

1938 BC. Then the rulers of Thebes, a

city far up the Nile in Upper Egypt,

defeated their enemies and reunited

Egypt. This began the Middle Kingdom,

which lasted until 1630 BC. During this

time, Egypt expanded its territory.

A second period of weakness followed

the Middle Kingdom. An Asian people

known as the Hyksos invaded Egypt.

The Egyptians finally forced out the

Hyksos by 1539 BC. This began the New

Kingdom, which lasted until 1075 BC.

A mighty pharaoh of the New Kingdom

was Thutmose III, who ruled from 1479

to 1426 BC. Thutmose’s reign was the

time of ancient Egypt’s greatest power

and wealth. Thutmose conquered Syria.

He also ordered the building of many

tombs and temples.

Later during the New Kingdom, the

Hebrews (the ancestors of Jewish

people) left Egypt, where they had been

slaves. This event, called the Exodus,

probably took place between 1279 and

1213 BC, during the reign of Ramses II.

Alexander and the Ptolemies

Peoples from Asia, first Assyrians and

then Persians, later took over Egypt.

Nefertiti was queen of ancient

Egypt from 1353 to 1336 BC. A

painted stone bust, or statue of

the queen’s head, can be seen

in the Egyptian Museum in Berlin.

114 Egypt, Ancient BRITANNICA STUDENT ENCYCLOPEDIA

Then in 332 BC Alexander the Great of

Macedonia (a country near Greece) conquered

Egypt. He founded the city of

Alexandria at the mouth of the Nile.

After Alexander’s death, Ptolemy, one of

his generals, seized the throne. In 323 BC

Ptolemy founded a new dynasty of

Egyptian kings, called the Ptolemies.

The Ptolemies were Macedonians who

spoke Greek, and many Egyptians disliked

having foreign rulers.

Nevertheless, under the Ptolemies Egypt

grew rich and powerful. They built the

Pharos, a huge lighthouse, at Alexandria.

Like the great pyramids, the Pharos was

one of the seven wonders of the ancient

world. The Ptolemies also built a famous

library at Alexandria. Scholars came

from all over the Greek-speaking world

to study there.

Roman and Muslim Conquests

The last of the Ptolemies was Queen

Cleopatra. Roman forces defeated her

navy at the battle of Actium in 31 BC. In

30 BC Egypt lost its independence to

Rome. After the Roman Empire split in

half in the AD 300s, Egypt became a part

of the eastern half, called the Byzantine

Empire.

Finally, in the AD 600s Muslim Arabs

took over Egypt. Egypt is still a Muslim

country today.

#More to explore

Cleopatra • Egypt • Hieroglyphics

• Mummy • Nile River • Pharaoh

• Pyramid • Re • Tutankhamen

Eiffel Tower

The Eiffel Tower in Paris, France, is

among the most famous landmarks in

the world. Known as the Tour Eiffel in

French, the tower was designed and

built by the French engineer Gustave

Eiffel in 1889.

The three-level tower is 984 feet (300

meters) tall. Glass-walled elevators and

stairs lead up to the first and second

platforms. Other elevators go from the

second level to the third platform near

the top. Along with viewing areas, the

tower has restaurants, a museum, and a

souvenir shop.

The Eiffel Tower is the result of a contest

held by the French government. At

the time the government was organizing

a fair to celebrate the 100-year anniversary

of the start of the French Revolution.

Eiffel’s plan was chosen from more

The Eiffel Tower is the tallest

structure in Paris, France.

BRITANNICA STUDENT ENCYCLOPEDIA Eiffel Tower 115

than 100 plans, though many people

criticized the plan because nothing like

it had ever been built before.

After the fair ended, the Eiffel Tower

was almost torn down several times. But

Eiffel oversaw changes to the structure

that made it more useful. Among them

were the additions of a weather station

in 1890 and a military telegraph station

in 1903. The tower is now a popular

tourist attraction.

#More to explore

French Revolution

Einstein, Albert

Albert Einstein was one of the greatest

geniuses in the history of science. He

developed many theories, or ideas. These

theories led to new ways of thinking

about space, time, matter, energy, and

gravity.

Early Life

Albert Einstein was born to Jewish parents

in Ulm, Germany, on March 14,

1879. He did not do well in school, but

he did take an interest in mathematics

and science. While at college, he studied

physics and math. After graduating in

1900, he worked in a government office.

Meanwhile, he continued studying

physics on his own.

Scientific Breakthroughs

In 1905 Einstein caused a stir by publishing

five major research papers. These

papers forever changed the way people

thought about the universe. One of

these papers contained completely new

ideas about the properties of light. Einstein

received the Nobel prize for physics

in 1921, mainly for the work in this

paper.

In another paper, Einstein presented

what is now called the special theory of

relativity. This theory states that measurements

of space and time are relative.

That is, they change when taken by

people moving at different speeds. This

idea was entirely new. The special theory

of relativity also changed how scientists

thought about energy and matter. (Matter

is everything that takes up space.)

Later Years

When the Nazi Party took over Germany

in 1933, Einstein left the country.

He eventually settled in the United

States.

DuringWorldWar II Einstein urged the

Albert Einstein United States to build nuclear weapons.

116 Einstein, Albert BRITANNICA STUDENT ENCYCLOPEDIA

He felt that these weapons might be

needed to defeat the Nazis. The United

States did create the first atomic bomb

in 1945. Einstein, however, did not

work to develop the bomb. AfterWorld

War II he tried to prevent any future use

of atomic weapons. Einstein died in

Princeton, New Jersey, on April 18,

1955.

#More to explore

Energy • Matter • Nuclear Energy

• Physics • Time • Universe

Eisenhower,

Dwight D.

A famous general duringWorldWar II,

Dwight D. Eisenhower became the 34th

president of the United States in 1953.

Eisenhower’s two terms in office were a

time of peace and prosperity.

Early Life

Dwight David Eisenhower was born in

Denison, Texas, on October 14, 1890.

He was the third of the seven sons of

David Jacob Eisenhower and Ida Elizabeth

Stover. Dwight spent most of his

childhood in Abilene, Kansas. He graduated

from the U.S. Military Academy at

West Point, New York, in 1915. In 1916

he married Mamie Geneva Doud. They

had two sons.

Military Career

DuringWorldWar I Eisenhower commanded

a tank training center. After the

war he served in the United States, the

Panama Canal Zone, Europe, and the

Philippines. He also was an aide to General

Douglas MacArthur.

During WorldWar II Eisenhower commanded

the U.S. forces in Europe. He

also led attacks in North Africa. In

December 1943 Eisenhower became

supreme commander of the Allied

forces. He led the invasion of France on

D-Day, June 6, 1944. That year Eisenhower

gained the highest U.S. military

rank, five-star general.

After the war Eisenhower served as

Army chief of staff until 1948. In 1950

he was named the first head of the

armies of the North Atlantic Treaty

Organization.

Presidency

In 1952 Eisenhower won the Republican

Party’s presidential nomination. His

vice presidential running mate was Senator

Richard M. Nixon. In the election

Eisenhower

was called Ike

from an early

age. His presidential

campaign

slogan

was “I like

Ike.”

Dwight D. Eisenhower

BRITANNICA STUDENT ENCYCLOPEDIA Eisenhower, Dwight D. 117

that November, Eisenhower easily

defeated the Democratic candidate,

Adlai E. Stevenson.

As president, Eisenhower helped to end

the KoreanWar in 1953. He tried to

ease the problems that had developed

between the United States and the

Soviet Union since the end ofWorld

War II. He also called for lower taxes

and less government control over the

economy.

Eisenhower suffered a heart attack in

1955. He recovered quickly, though,

and decided to seek a second term. In

the 1956 election he defeated Stevenson

again.

Eisenhower now faced serious problems

at home and abroad. At home his biggest

challenge was the integration of

schools. Some people thought that African

American students should not be

allowed to attend the same schools as

white students. In 1954 the Supreme

Court had said they should be allowed

to attend the same schools. But in 1957

the governor of Arkansas kept nine African

American students from entering a

high school in Little Rock. Eisenhower

sent federal troops to protect the students

from angry whites.

Also in 1957 the Soviet Union launched

the first artificial satellite, Sputnik 1,

into space. The United States raced to

put its own satellite, Explorer 1, into

orbit in 1958. That year Eisenhower

approved the creation of the National

Aeronautics and Space Administration

(NASA).

Hoping to improve relations with other

countries, Eisenhower toured many

parts of the world. In 1959 he

welcomed Soviet premier Nikita

Khrushchev to the United States. After

the Soviets shot down a U.S. spy plane

over Soviet territory, however, Eisenhower

did not make his planned visit to

the Soviet Union.

October 14, March 28,

1890 1943 1952 1957 1959 1961 1969

Eisenhower

is born in

Denison, Texas.

Eisenhower

gains command

of the Allied

forces in

Europe during

World War II.

Eisenhower is

elected

president.

Eisenhower

forces Little

Rock, Arkansas,

to allow black

students into an

all-white school.

The leader of

the Soviet Union

meets with

Eisenhower in

the United

States.

Eisenhower’s

second term

ends.

Eisenhower

dies in

Washington,

D.C.

T I M E L I N E

118 Eisenhower, Dwight D. BRITANNICA STUDENT ENCYCLOPEDIA

Retirement

Eisenhower’s vice president, Nixon, lost

to John F. Kennedy, a Democrat, in the

election of 1960. The following January

Eisenhower retired to his farm in Gettysburg,

Pennsylvania. He died of heart

failure inWashington, D.C., on March

28, 1969.

#More to explore

Kennedy, John F. • KoreanWar • Nixon,

Richard M. • North Atlantic Treaty

Organization • United States •World

War II

Electoral College

Every four years, millions of citizens

vote for president and vice president of

the United States. But the citizens’ votes

(called popular votes) do not directly

elect these leaders. Their votes actually

elect the 538 members of a group called

the electoral college. The electoral college

then elects the president and vice

president.

How Electors Are Chosen

The electoral college is organized by

states. Each state gets a certain number

of electors—the people who vote in the

electoral college. A state’s number of

electors equals its number of senators

and representatives combined. Every

state has two senators. The number of

representatives is based on the population

of the state, though every state has

at least one representative. In addition,

the District of Columbia (Washington,

D.C.) gets three electors.

The United States has two main

political groups, or parties (the

Democrats and the Republicans). Each

political party chooses a candidate for

president and a candidate for vice

president. In each state, each party also

chooses a group, or slate, of electors.

The electors promise to vote for their

party’s candidates. When citizens vote

for the candidates of one party, they are

actually choosing that party’s electors

for their state.

In most states, the party that wins the

most popular votes sends all its electors

to vote in the electoral college. (Maine

and Nebraska choose electors slightly

differently.) The electors for every state

then vote for their party’s candidates.

The candidates with the most electoral

All the electors

do not meet in

one place to

vote. Instead,

every state has

its own

gathering.

A certificate from Alabama

shows the signatures of the

state’s electors in 2000. The nine

electors voted for George W.

Bush.

BRITANNICA STUDENT ENCYCLOPEDIA Electoral College 119

votes become president and vice

president.

History

The electoral college came about partly

because the people who wrote the U.S.

Constitution did not trust the common

voters. In most elections there have been

few complaints about the process. Usually,

the candidates who win the most

popular votes also win the most votes in

the electoral college. But this is not

always so. In the 2000 election, more

citizens voted for Al Gore than for

GeorgeW. Bush. However, Bush

became president. This happened

because Bush’s party won in enough

states to send the most electors to the

electoral college. Besides Bush, two

other U.S. presidents have been elected

with fewer popular votes than their

opponents. They were Rutherford B.

Hayes in 1876 and Benjamin Harrison

in 1888.

#More to explore

Political Party • United States

Constitution

Electricity

Electricity is a form of energy. It can be

seen in nature in a bolt of lightning.

Scientists have also learned how to generate,

or create, electricity. This is useful

because electricity that is generated can

be controlled and sent through wires. It

can then power such things as heaters,

lightbulbs, and computers. Today electricity

provides most of the energy to

run the modern world.

How ElectricityWorks

Everything in the universe is made of

tiny particles called atoms. Each atom

has even tinier particles called protons

and electrons. An electron has what is

called a negative charge. A proton has a

positive charge. Positive and negative

charges try to move close together. However,

two positive charges, or two negative

charges, will push each other away.

Electricity results when electrons are

pushed and pulled from atom to atom.

Static Electricity

The electrons can be moved by actually

rubbing one object against another. This

creates something called static electricity.

Static electricity explains why rubbing a

balloon against one’s hair can make the

hair stand on end. The electrons move

from the balloon to the hair. Because the

hairs then all have the same kind of

charge, they try to fly away from each

other.

Generating Electricity

Many moving electrons are called an

electric current. A city’s power plant

Electricity in the form of lightning brightens

the sky above a city.

120 Electricity BRITANNICA STUDENT ENCYCLOPEDIA

produces a powerful electric current and

sends it through wires. The electricity

used for lighting, heating, and running

appliances is made by machines called

generators. Generators cause a current to

flow by moving a magnet past a coil of

wire.

Wires then carry the current to houses

and other buildings. More wires connect

to the power outlets in rooms. When a

person plugs in an iron, hair dryer, or

another electric device, the current travels

into the device. The current then

makes the device work. A chemical reaction

in a battery can also produce an

electric current.

History

The ancient Greeks were the first to

study electric forces. In the American

colonies during the 1700s, Benjamin

Franklin performed experiments that

proved that lightning is a form of electricity.

Scientists later learned that electricity

is related to magnetism. They

then learned how to generate electricity

using magnets.

#More to explore

Atom • Battery • Energy • Magnet and

Magnetism

Electronic Games

Electronic games are games run by

computer technology. They are also

called video games. People play

electronic games on personal

computers, in video arcades, and on

home electronic game systems. The

home systems are called consoles.

Console games are played using a

handheld device usually connected to a

television. People may play electronic

games alone or with others.

How Electronic GamesWork

All electronic games begin as computer

instructions called software. A computer

Static electricity makes a child’s

hair stand on end.

Some electronic games are small and can

be held in the hand.

BRITANNICA STUDENT ENCYCLOPEDIA Electronic Games 121

programmer writes the software commands

to make the game run. The game

software is then loaded onto

hardware—a computer or a console.

Inside the computer or the console,

hardware and software work together to

send electronic signals through the system.

These signals create the game’s

sounds and images. The player controls

the action of the game using a paddle, a

joystick, or a keypad.

History

Electronic games began as very simple

programs with poor graphics and no

sound. A man named William A. Higinbotham

created one of the first electronic

games, called Tennis for Two, in

1958.

The first arcade game, called Computer

Space, came out in 1971. More successful

arcade games soon followed—for

example, Pong, Space Invaders, and Pac-

Man. The first electronic game system

for home use appeared at about the

same time.

In 1977 a company called Atari released

a home system with removable cartridges.

Each cartridge held a different

game.With this system electronic games

grew in popularity. But people wanted

better graphics and sound.

Seeing the demand, many other companies

began developing home electronic

games as well. The quality of the games’

sound and images steadily improved.

The technology used to run the games

also improved.

Nintendo was the first company to provide

a keypad with its consoles rather

than just a joystick. Today Nintendo,

Sony, and Microsoft are some of the

leading makers of electronic games and

game systems.

Game companies continue to add new

features to their games. Some systems

now let players play together over telephone

lines. Electronic gaming has

become one of the most popular forms

of entertainment in the world.

#More to explore

Computer • Electronics

Electronics

Electronics is a branch of the science

called physics. It explains how electricity

can be used to carry or process information.

Many products are based on electronics.

They include computers, digital

cameras, radios, television sets, wireless

telephones, and video games. Often

these products themselves are called electronics.

Electric Signals

Electronic products contain devices that

control the flow of electricity. A flow of

electricity is called an electric current.

Changes in electric currents create electric

signals. Electric signals can provide

different kinds of information. For

example, electric signals in a radio provide

sound.

Many electronic products use electric

signals to provide information as a number

code. These products are called digi-

Other early

arcade video

games that

were popular

include Ms.

Pac-Man,

Donkey Kong,

Centipede,

Asteroids, and

Frogger.

122 Electronics BRITANNICA STUDENT ENCYCLOPEDIA

tal electronics. A digital camera is an

example. It changes a picture into many

tiny dots and uses electric signals to create

numbers that describe each of the

dots. Another digital electronic product,

such as a computer or a printer, can also

read those numbers. They can use the

numbers to re-create the picture and

print it or display it on a computer

screen.

Electronic Devices

Most electronic devices, including computer

chips and transistors, are made

from silicon. Silicon is a type of material

called a semiconductor. A semiconductor

lets electricity flow through it only

under certain conditions. This property

makes it useful for controlling the flow

of electricity.

One of the most common electronic

devices is the transistor. It controls the

flow of electricity by acting as a switch

that can be turned on and off. Transistors

can be very small. Millions of tiny

transistors can be combined into one

device called an integrated circuit. This

allows electronic products to work with

a large number of electric signals very

quickly.

#More to explore

Computer • Electricity • Physics

Element

#see Chemical Element.

Elephant

Elephants are the largest living land animals.

There are three species, or kinds:

the African savanna elephant, the African

forest elephant, and the Asian

elephant. They make up the elephant

family of mammals. Mammoths and

A worker puts together an integrated circuit,

or microchip. Microchips allow electronic

products to work quickly and to be

small in size.

African elephants are the largest of all living

land animals.

BRITANNICA STUDENT ENCYCLOPEDIA Elephant 123

mastodons also belonged to this family,

but they are now extinct.

Where Elephants Live

Elephants live mainly in forests and

grasslands in warm areas. African

elephants live in Africa. The Asian

elephant lives in India, Sri Lanka,

Malaysia, Indonesia, Thailand, and Vietnam.

Physical Features

Elephants’ skin is thick, wrinkled, and

not very hairy. It is grayish to brown in

color. An elephant’s trunk is an extension

of the nose and upper lip. An

elephant uses its trunk to grab food and

to put it into the mouth. It can also

draw water into the trunk and then

blow it into the mouth.

An African elephant has larger ears and a

slightly larger body than an Asian

elephant. African elephants may stand

up to 13 feet (4 meters) at the shoulder.

The Asian elephant may reach about

11.5 feet (3.5 meters) at the shoulder.

Male African and Asian elephants usually

have two tusks, which are long

upper teeth. Female African elephants

have tusks, too, but most female Asian

elephants do not.

Behavior

Elephants migrate, or travel, in search of

food. They eat only plants, including

grasses. They often rest during the hottest

hours of the day. They lie down to

sleep for only a few hours at night.

Elephants move around in small family

groups led by older females, called cows.

A family group has two to eight animals.

Several groups form a herd. A herd

includes as many as 20 to 40 cows and

all their babies. Cows are very protective

of the young in their herd. At about age

4, the male young move away from the

herd. They join separate groups of

males, called bulls.

Life Cycle

A baby elephant is born about 22

months after mating. A newborn

elephant is about 3 feet (1 meter) tall

and weighs about 220 pounds (100 kilograms).

An elephant may live for 60 to

70 years.

Elephants and Humans

Humans have used elephants for transportation

and as work animals since

ancient times. People in Asia still use

elephants for these purposes today. In

An Asian elephant bathes in the Kabani

River in India.

124 Elephant BRITANNICA STUDENT ENCYCLOPEDIA

addition, trained elephants appear in

circuses throughout the world.

However, human activities have endangered

the survival of wild elephants.

Humans have destroyed many elephant

habitats. Humans also have killed many

elephants for the ivory of their tusks.

Humans carve this ivory into works of

art, jewelry, and other objects.

#More to explore

Endangered Species • Mammal

• Mastodon and Mammoth

El Greco

#see Greco, El.

Elizabeth I

Elizabeth I was queen of England for

almost 45 years. During that time her

country became very powerful. Her

reign is remembered as the Elizabethan

Age.

Early Life

Elizabeth was born in Greenwich,

England, on September 7, 1533. Her

father was King Henry VIII. Her

mother, Anne Boleyn, was the second of

Henry’s six wives. Henry had Anne

Boleyn put to death when Elizabeth was

only 3 years old.

Elizabeth had an older half sister named

Mary and a younger half brother named

Edward. Edward became king in 1547

and died in 1553. Mary then became

queen. Henry, Edward, and Elizabeth

were Protestant, but Mary was Roman

Catholic. She made Catholicism the

national religion and put Elizabeth in

prison for a time.

Reign

Mary died in 1558, and Elizabeth was

crowned queen of England. She was 25

years old. She had received a good education

and was well prepared to rule.

Many men wanted to marry her, but she

stayed single. This gave her more power,

but it also put her cousin Mary Stuart

next in line for the throne. Mary Stuart,

also known as Mary Queen of Scots, was

a Catholic. Elizabeth kept her in prison

for many years and then had her killed

in 1587.

During the first 30 years of Elizabeth’s

reign, England built up its sea power.

English ships sailed across the Atlantic

Ocean to theWest Indies and chal-

Elizabeth I lenged Spain for control over trade.

Elizabeth’s

family name

was Tudor.

She was

sometimes

called Good

Queen Bess.

BRITANNICA STUDENT ENCYCLOPEDIA Elizabeth I 125

English sea captains raided Spanish

ships, and Elizabeth took a share of the

treasure they seized.

King Philip II of Spain struck back in

1588. He sent a great fleet called the

Armada to attack England. The queen’s

ships defeated the Armada. That victory

was a high point of Elizabeth’s reign.

During the 1590s Elizabeth began to

suffer from ill health. She died on

March 24, 1603. Mary Stuart’s son,

James VI of Scotland, became king of

England.

#More to explore

Armada, Spanish • Henry VIII

Elizabeth II

At the age of just 25, Elizabeth II

became queen of the United Kingdom

of Great Britain and Northern Ireland.

She came to the throne after the death

of her father, King George VI, in 1952.

Elizabeth Alexandra Mary was born in

London, England, on April 21, 1926.

Her father was the second son of King

George V, who died in 1936. George

V’s oldest son reigned as King Edward

VIII for only a short time. Then he

surprised the world by giving up the

throne. Elizabeth’s father took over as

King George VI. As a result, the

10-year-old Elizabeth became next in

line for the throne. The young princess

began training for her future duties. She

also studied history, languages, and

music at home. In 1940 she gave her

first radio address.

Elizabeth married Philip Mountbatten

in 1947. Before the marriage he gained

several special titles, including the duke

of Edinburgh. Their first child, Prince

Charles, was born in 1948. Their

younger children are Princess Anne,

born in 1950; Prince Andrew, born in

1960; and Prince Edward, born in 1964.

Their family name isWindsor.

On February 6, 1952, King George VI

died. Elizabeth became Queen Elizabeth

II. Her coronation, or crowning ceremony,

took place on June 2, 1953.

As queen, Elizabeth does not control the

British government. Instead, she serves

as a symbol of her country at ceremonies

and public events in Britain and around

the world.

#More to explore

Elizabeth II United Kingdom

126 Elizabeth II BRITANNICA STUDENT ENCYCLOPEDIA

Elk

The term elk refers to different animals

in different parts of the world. In

Europe it is used for the mammal

known in North America as the moose.

The name is also used for several large

deer, notably the animal sometimes

called the American elk in North

America. The American elk is more

properly named the wapiti.

#More to explore

Deer • Moose •Wapiti

Ellis Island

Ellis Island was once the first place that

many people saw when they moved to

the United States from other countries.

People who go to a new country to live

are called immigrants. Throughout its

history the United States has welcomed

many immigrants. Many of them

arrived by boat at Ellis Island. The island

is located in the bay near New York City.

Before 1890 the states handled immigration.

Then the U.S. government took

over. It built the immigration center on

Ellis Island at a time when many people

wanted to live in the United States.

More than 12 million people passed

through the center from 1892 to 1924.

The busiest year was 1907, when 1.25

million people passed through.

On Ellis Island, doctors and inspectors

examined the immigrants. They checked

for disease and wrote down information

about each person. Then they decided

who could stay in the United States.

Most people passed the tests and went

on to New York City after a few hours.

Others failed their examinations. Some

had serious diseases. Others were seen as

troublemakers. These people waited on

the island for a ship to take them back

home.

In 1924 Congress passed a law that

made it harder to immigrate to the

United States. Those who did come

passed through other places. Ellis Island

mainly held people who were having

Ellis Island covers only about 27 acres (11

hectares), but it used to be even smaller. It

was built up with boatloads of rocks and dirt.

A male American elk, or wapiti, lifts his

head to sound a call.

BRITANNICA STUDENT ENCYCLOPEDIA Ellis Island 127

immigration problems. In 1954 the center

on Ellis Island closed. In 1976 the

island became a tourist center, and in

1990 the immigration center reopened

as a museum. Today many people visit

Ellis Island on their way to the nearby

island that has the Statue of Liberty.

#More to explore

Liberty, Statue of • United States

Elm

Several species, or types, of tree belong

to a family of plants called the elm family.

Large numbers of elms used to grow

in cities. During the 1900s, however, a

disease killed many elms.

Elms grow mainly in the Northern

Hemisphere. North American elms

include the American elm; the slippery,

or red, elm; the rock, or cork, elm; the

winged, or wahoo, elm; and the cedar

elm. The English elm and the Wych elm

are European species. Asian elms include

the Siberian elm and the Chinese elm.

Elms are often about 50 to 70 feet (15

to 21 meters) tall. But some types may

grow higher than 100 feet (30 meters).

The leaves of elms are toothed, which

means that they have jagged edges. The

flowers do not have petals. They grow in

clusters. The fruits, called samaras, are

flat disks that each hold one seed.

People often plant elms because they

grow quickly into beautiful shade trees.

People use elm wood to make boats,

farm buildings, or furniture.

Dutch elm disease has killed many

North American and European elm

trees. A fungus carried by beetles causes

this disease.

#More to explore

Tree

An American elm provides much shade.

Immigrants at Ellis Island in the early 1900s

wait to have a physical examination. Doctors

and inspectors decided who was

healthy enough to be allowed to stay in the

United States.

128 Elm BRITANNICA STUDENT ENCYCLOPEDIA

El Salvador

El Salvador is the smallest of the seven

countries in Central America. It is also

the most crowded. Its capital is San Salvador.

Geography

The Pacific Ocean forms El Salvador’s

southern border. The country shares

land borders with Guatemala and Honduras.

El Salvador has two mountain

regions with volcanoes. Lowlands along

the coast are generally hot and humid.

Temperatures are cooler in the mountains.

Plants and Animals

Balsa, cedar, mahogany, coconut,

mango, and palm trees grow in El Salvador.

However, many of its forests have

been cleared to make room for farming.

Wilderness preserves protect spider

monkeys, anteaters, mountain lions, and

hummingbirds.

People

Nearly 90 percent of El Salvadorans are

mestizos, or people with mixed American

Indian and European roots. Most

other people are Indians, including the

Izalco and the Pancho. Spanish is the

main language. Most people practice

Roman Catholicism. More than half of

the population lives in cities.

Economy

El Salvador’s economy is based on

manufacturing and farming. Factories

produce mainly food products and

clothing. Clothing and coffee are the

most important exports. Sugarcane and

corn are other important crops.

History

The Pipil Indians probably arrived in

what is now El Salvador about 1,000

years ago. The Spanish reached the

region in 1524 and defeated the Pipil by

1539. Spain ruled the land as a part of

Guatemala until 1821. In 1823 El Salvador

joined the United Provinces of Central

America, a union of five states

formerly ruled by Spain. When the

union broke up, El Salvador became

independent in 1840.

Decades of political violence grew into

civil war by the end of the 1970s. Government

and rebel leaders finally signed

a peace treaty in 1992.

..More to explore

Central America • San Salvador

Facts About

EL SALVADOR

Population

(2008 estimate)

5,794,000

Area

8,124 sq mi

(21,042 sq km)

Capital

San Salvador

Form of

government

Republic

Major cities

San Salvador,

Soyapango,

Mejicanos, Santa

Ana, San Miguel

BRITANNICA STUDENT ENCYCLOPEDIA El Salvador 129

Emancipation

Proclamation

The American CivilWar pitted Southern

states against Northern states. One

of the major issues was whether the

Southern states should be allowed to

continue owning slaves. During the war,

President Abraham Lincoln issued the

Emancipation Proclamation. This document,

issued on January 1, 1863,

declared that the slaves in the Southern

states were free.

The president could not really enforce

the proclamation in places that were still

controlled by Southern troops. Even so,

the proclamation was important because

it made the American CivilWar a fight

about slavery.

The proclamation also opened the U.S.

Army to freed African Americans. As

soon as the Northern armies captured a

region, the slaves there were given their

freedom. Nearly 180,000 of them joined

the Northern forces. They were very

helpful in bringing about the final surrender

of the Southern forces in 1865.

After the war, the 13th Amendment to

the U.S. Constitution ended slavery

throughout the United States.

#More to explore

American CivilWar • Lincoln, Abraham

• Slavery

Empire

Throughout history countries have

wanted to control lands beyond their

borders. This practice is called imperialism,

and the lands that they control are

called an empire. The ruler of an empire

is sometimes called an emperor. Countries

build empires mainly to get power

or wealth.

Building Empires

Sometimes a ruler builds an empire by

taking over nearby lands. One famous

empire of this type was the Roman

Empire of ancient times. The Romans

spread their power from the city of

Rome to lands in Europe, North Africa,

and western Asia.

An empire may also consist of lands far

from the controlling country. Sometimes

a country sends people to live in a new

place overseas. The settlements that

those people set up are called colonies.

In the 1600s, for example, England sent

people to set up colonies in eastern

North America. Those colonies eventually

became the United States.

Sometimes, instead of sending many

settlers, a country sends only a few

President Abraham Lincoln called the

Emancipation Proclamation “the greatest

event of the 19th century.”

130 Emancipation Proclamation BRITANNICA STUDENT ENCYCLOPEDIA

people to govern the new place. Those

places are often called colonies as well.

In the 1800s, for example, European

countries seized control of most of

Africa. In most cases only a small number

of Europeans went to the colonies in

Africa. They oversaw the government of

the colonies. They also set up businesses

and controlled trade. Sometimes the

European colonizers forced the Africans

to work for them.

Effects of Empires

Imperialism has had a great influence on

world history. It has led to the discovery

and development of new lands. Imperial

powers have built useful things such as

roads, schools, and hospitals. Imperialism

has also spread knowledge and culture.

In many places that were once

colonies, the people still speak the language

of the colonizers. The religions of

colonial powers are also common in

former colonies.

Imperialism has also had many negative

effects. Imperial powers killed many

native people in wars of conquest. They

made other native people work for low

wages or as slaves. They also often forced

the people to give up their traditional

way of life.

History

The Phoenicians were among the earliest

colonizers. About 3,000 years ago they

set up trading posts along the eastern

coast of the Mediterranean Sea, in

North Africa, Anatolia (now Turkey),

and Cyprus. Later the Assyrians, the

Persians, the Greeks, and the Romans

had empires in the region. The Roman

Empire reached all the way from Britain

to Egypt.

Imperialism also happened in Asia. The

first empire in India was established in

the 300s BC. In China the Qin Dynasty

created the first empire in 221 BC.

After the fall of the Roman Empire in

the AD 400s, no European country was

Great Britain ruled land all over the world

from about the 1600s to the 1900s. A map

shows the huge size of the British Empire in

the late 1800s. The British lands are shown

in orange.

The Romans built Hadrian’s Wall across

Great Britain in ancient times. It included a

long stone wall and forts to keep invaders

out of the Roman colony in Britain.

BRITANNICA STUDENT ENCYCLOPEDIA Empire 131

strong enough to establish colonies.

Between the 600s and the 1200s Arabs

built up an empire in western Asia,

North Africa, and Spain. They spread

their religion, Islam, to the places they

conquered.

In the late 1400s European explorers

first crossed the Atlantic Ocean to the

Americas. That began a great age of

exploration. Soon European countries

began claiming land in the Americas,

India, and the East Indies. England,

France, Spain, Portugal, and the Netherlands

had many colonies.

Most colonies in North and South

America gained freedom between 1776

and 1826. But at the same time European

countries started building empires

in Africa. In the 1880s European powers

divided up almost all of Africa between

themselves.

In the late 1800s and early 1900s the

United States and Japan became colonial

powers. The United States took control

of islands in the Caribbean Sea and the

Pacific Ocean. Japan conquered lands in

East Asia. Imperialism by Japan, Italy,

and Germany in the 1930s led toWorld

War II. After the war the Soviet Union

built an empire in eastern Europe.

The large empires of the past no longer

exist. Between 1945 and 1990 about

100 colonies gained their freedom.

Sometimes this happened peacefully,

with the colonial power stepping aside.

Other times the people of the colonies

fought for independence.

#More to explore

Africa • Americas, Exploration and

Settlement of the • Colony • Greece,

Ancient • Phoenician • Rome, Ancient

Encephalitis

Encephalitis is an inflammation, or

swelling, of the brain. It is often a mild

illness, but serious cases can cause brain

damage.

Particles called viruses or such tiny living

things as bacteria and parasites can cause

encephalitis. So can harmful chemicals.

Viruses are the most common cause.

The viruses that cause chicken pox,

mumps, and measles can turn into

encephalitis. These viruses spread from

person to person. Mosquitoes and other

biting insects also spread viruses. Some

Great Britain gave Hong Kong

back to China in 1997. Hong

Kong was the last major colony

of the British Empire. Members

of the Chinese military attend a

ceremony marking the peaceful

return of the colony.

132 Encephalitis BRITANNICA STUDENT ENCYCLOPEDIA

of these viruses, such as West Nile virus,

can cause encephalitis.

Encephalitis has a wide range of symptoms,

or signs. These include fever,

headache, tiredness, a stiff neck, and

vomiting. In the most severe cases

people may fall into a coma. A coma is a

deep, heavy sleep. Recovery in severe

cases can take weeks. There may be

damage to the brain that cannot be

fixed.

Doctors use medicines to fight the

causes of encephalitis and to ease its

symptoms. The best way to prevent

encephalitis is to stop the spread of the

things that cause it.Washing hands

helps to kill viruses and bacteria. Insect

repellent helps to keep insects from biting.

Vaccines prevent many illnesses that

can cause encephalitis. Vaccines are substances

given to healthy people that help

the body fight disease.

#More to explore

Brain • Virus

Endangered

Species

An endangered species is any type of

plant or animal that is in danger of disappearing

forever. If a species, or type, of

plant or animal dies out completely, it

becomes extinct.

How Plants and Animals

Become Endangered

Animals and plants depend on each

other and their environment to survive.

When their environment, or habitat,

changes or disappears, plants and animals

may become endangered. Natural

The California condor was

hunted and poisoned until it

became an endangered species.

Now it is protected by law.

An X-ray photograph shows encephalitis on

the right side of a brain.

BRITANNICA STUDENT ENCYCLOPEDIA Endangered Species 133

disasters or changes in the climate can

harm or destroy habitats.

Humans can cause species to become

endangered as well. Humans pollute

habitats with garbage, car fumes, and

factory wastes. They destroy habitats by

clearing land for roads, buildings, and

farms. They also may hunt and kill too

many of certain types of animals.

The arrival of a new species in a habitat

is another threat. Often the new species

spreads freely because it has no natural

enemies. The species already in the habitat

may not be able to compete against

the newcomer. For example, mongooses

brought to Jamaica in the 1800s killed

many native animals.

Endangered Species Today

The list of endangered animals includes

many large, well-known mammals. The

tiger and both African and Asian

elephants are endangered. Several types

of whale are also endangered. The giant

panda survives only in remote parts of

China and in zoos.

Endangered birds include several types

of crane, eagle, and parrot. Among the

endangered reptiles are several types of

sea turtle—for example, the leatherback

turtle. There are also endangered

amphibians, fishes, mollusks, insects,

and other animals.

Endangered plant species range from

tiny mosses to towering trees. The mandrinette

is an endangered shrub with

bright red flowers. Foreign species of

plant have been taking over its habitat

on the island of Mauritius. In the early

21st century fewer than 50 of these

plants were growing in the wild.

Another endangered plant, the Bermuda

cedar tree, grows in the wild only in

Bermuda. People have cut down many

of these trees to build houses, ships, and

furniture.

Protection

In the 1960s people became aware that

many species were endangered. Today

many countries have made it illegal to

harm, capture, kill, or sell endangered

species. In addition, many organizations

work to keep endangered species from

becoming extinct. The International

Union for Conservation of Nature and

Natural Resources keeps lists of endangered

species. The Nature Conservancy

and theWorldWildlife Fund help to set

aside land for threatened wildlife.

Nature preserves and zoos help endangered

animals to reproduce. Such programs

have helped to increase the

populations of the black-footed ferret,

the California condor, and other endangered

animals.

#More to explore

Animals, Extinct • Conservation

• Environment • Habitat

Endocrine

System

In the human body, a group of organs

called glands make up the endocrine

system. Glands make hormones. These

are chemicals that help control activities

of the body. Insects, fish, amphibians,

One endangered

species

that was saved

from extinction

is a bird called

the whooping

crane. In

1937 fewer

than 20

remained.

Now there

are several

hundred.

134 Endocrine System BRITANNICA STUDENT ENCYCLOPEDIA

reptiles, birds, and mammals all have

endocrine systems.

Glands

The glands of the human endocrine

system make more than 20 major hormones.

The hormones travel in the

blood to cells throughout the body. A

part of the brain called the hypothalamus

helps to control the release of many

hormones.

The major glands of the endocrine system

include the pituitary, thyroid, and

adrenal glands, as well as the pancreas.

The ovaries are glands found only in

women. Men have glands called testes.

Pituitary Gland

The pituitary gland is a bean-sized gland

at the base of the brain. It sits beneath

the hypothalamus. The pituitary gland

makes hormones that control many

body functions. One hormone controls

the growth of the body. Another helps

women deliver babies and helps produce

milk so that women can nurse their

babies. Other hormones made by the

pituitary gland control how other endocrine

glands work.

Thyroid and Parathyroid Glands

The thyroid gland is located at the base

of the neck. It produces a hormone that

controls how fast cells burn food to

release energy. Four parathyroid glands

are attached to the thyroid gland. They

make a hormone that helps control the

amount of calcium in the blood. Calcium

is an important mineral that helps

bones to grow.

Most glands of the endocrine system are

found in both women and men. Only

women have ovaries. Only men have testes.

BRITANNICA STUDENT ENCYCLOPEDIA Endocrine System 135

Adrenal Glands

One adrenal gland sits on top of each

kidney. The two adrenal glands are

divided into two main parts. One part

produces hormones that do many jobs.

For example, they control the mixture of

salt and water in the body. The other

part makes hormones that raise blood

pressure and heart rate when the body is

under stress.

Pancreas

The pancreas is located just behind the

stomach. This gland produces two

important hormones called insulin and

glucagon. They work to keep the right

amount of sugar in the blood.

Ovaries and Testes

Ovaries sit in the pelvis, or lower belly,

of females. They make hormones that

cause breasts, wide hips, and other

female features to develop. Testes sit in a

pouch behind the penis in males. They

make hormones that cause a deep voice,

facial hair, and other male features to

develop. In addition to hormones, ovaries

produce female sex cells, or eggs,

and testes make male sex cells, or sperm.

For this reason, ovaries and testes also

belong to the reproductive system.

Problems with the Endocrine

System

Diseases of the endocrine system cause

the glands to make too much or too

little of a hormone. One type of the

disease called diabetes happens when the

pancreas does not produce enough insulin.

If the pituitary gland does not make

the right amount of growth hormone,

children will grow too much or too

little.

Problems with the thyroid gland can

cause many symptoms. Too much thyroid

hormone in the blood causes

weight loss, a high heart rate, nervousness,

sweating, bulging eyes, and a swelling

in the neck. Too little thyroid

hormone causes weight gain, a slow

heart rate, dry skin, and a feeling of

tiredness.

#More to explore

Diabetes • Hormone • Pancreas

One of the hormones made by the pituitary

gland controls the growth of the body.

136 Endocrine System BRITANNICA STUDENT ENCYCLOPEDIA

Energy

Energy is another word for power.

Energy makes things move. It makes

machines work. Energy also makes living

things grow.

Types of Energy

Energy exists in many different forms.

Animals get energy from eating food.

Electrical energy is associated with the

tiny units called atoms that make up

everything in the universe. The energy is

created when particles called electrons

move from one atom to another. Heat

and light are also forms of energy. One

form of energy can also be transferred

into another. Through a battery, stored

chemical energy changes into electric

energy. In a lightbulb, electric energy

changes to light and heat.

Each of these forms of energy can be

described as either potential energy or

kinetic energy. Potential energy is

stored energy. An object with potential

energy has the ability, or potential, to

move. Potential energy comes from the

position or the shape of an object. For

example, potential energy is stored in a

rock perched on a cliff and in an arrow

stretched back on a bowstring. If the

cliff crumbles under the rock, the rock

falls. If the string is let go, it moves

forward and pushes the arrow through

the air.

As the rock and the arrow move, they

gain kinetic energy. Kinetic energy is the

energy of moving things. All moving

objects have kinetic energy—even

atoms.

Sources of Energy

The sun is the source of almost all

energy on Earth. The sun makes plants

grow. When animals eat the plants they

gain energy from the chemicals that

make up the plants. When plants die

they decay, or break down. Over millions

of years this process creates what

are called fossil fuels. Fossil fuels include

petroleum, natural gas, and coal. These

are used to run factories, heat homes,

and power automobiles.

Fossil fuels pollute the atmosphere

when they are used. They are also being

used up very quickly. Scientists

therefore have tried to find other

sources of energy to replace the fossil

fuels. Some of these sources have been

used directly for many years. These

include wind, water, and heat from

Earth. Sailboats harness the power of

the wind to move them along. Water

mills use water flowing through rivers

to turn wheels that grind grain. In

ancient times some people used hot

water and gases from Earth to heat

Wind turbines in California produce electricity.

BRITANNICA STUDENT ENCYCLOPEDIA Energy 137

People

The people of England are a mixture of

many different ethnic groups. The early

people of the area were called Celts.

Invaders from Germany, Denmark,

France, and other parts of Europe came

later. Most of the English people are

descendants of these peoples. People

from Asia, Africa, and the Caribbean

islands make up smaller groups. Most of

the population lives in cities.

Most of England’s people are Christian.

The Church of England, which is Protestant,

is the country’s official church.

There are also large groups of Muslims,

Sikhs, Hindus, and Jews.

Economy

Services such as tourism, banking, and

insurance are the most important part of

the English economy. London is a major

world center for finance. Manufacturing

businesses make foods, chemicals, textiles,

computers, automobiles, and aircraft.

England’s major crops include

wheat, barley, and potatoes and other

vegetables. Cattle and sheep are raised

for meat and milk.

History

People have lived on the land that is

now England for thousands of years.

The Celts lived there as early as 500 BC.

The Romans came later. In the AD 400s

and 500s three peoples from northern

Europe—Angles, Saxons, and Jutes—

conquered England. Their language,

Anglo-Saxon, later developed into

English. The region became known as

“Angle-land,” which later became

“England.”