Britannica Student Encyclopedia - 2010

services. A scout may also earn merit

badges for learning new skills or studying

new subjects.

The basic scouting group is called a

troop. Scouts from many troops meet in

gatherings called jamborees. A world

jamboree takes place about every four

years. As the 21st century began, more

than 25 million children and teenagers

from more than 200 countries were

active in the Boy Scouts.

Girl Scouts

Very soon after the Boy Scouts began,

many girls became interested in scouting.

In 1910 Baden-Powell started the

Girl Guides. Juliette Gordon Low

started the Girl Scouts of the U.S.A. in

1912.

Girl Scouts serve their communities and

countries in many ways. For example,

they may gather food and clothing for

the needy, help others learn to read, or

work to protect the environment. Since

the mid-1930s, Girl Scouts in the

United States have sold cookies to raise

money.

Like the Boy Scouts, the Girl Scouts are

divided into age groups. A girl as young

as 5 years old can be a Daisy Girl Scout.

The Brownie Girl Scouts are 6 to 8, and

Junior Girl Scouts are 8 to 11. Girl

Scouts can be as old as 17 years. Girls,

like boys, earn badges as a sign of their

accomplishments.

The World Association of Girl Guides

and Girl Scouts started in 1928. By the

early 21st century, the association had

more than 10 million members from

140 countries.

#More to explore

Citizenship

Sculpture

Sculpture is a branch of the visual arts. It

involves the creation of artistic objects in

three dimensions—length, width, and

height. The main feature of a sculpture’s

Indonesian Girl Scouts salute their country’s

flag.

The highest

rank in the

Boy Scouts of

America is the

Eagle Scout.

54 Sculpture BRITANNICA STUDENT ENCYCLOPEDIA

design is the way its forms extend

through space. Size, texture, light and

shade, and color are also important

design elements. A sculpture may look

exactly like a person or object or may

reflect shapes and forms that the artist

invents.

Sculpture may be either in the round or

in relief. A sculpture in the round stands

on its own. It can be viewed from all

sides. A relief is attached to a background,

so it is not designed to be

viewed from the back. Reliefs often

decorate buildings.

Materials

Clay has been one of the sculptor’s chief

materials since ancient times. Clay is

easy to obtain and to use. Once early

peoples learned to make bronze, metals

became a popular choice for sculpture as

well. Most metals are very strong and

long-lasting. Sculptors value their color

and shine. Wood has long been a popular

material for carving. It is one of the

main materials used by sculptors in

Africa and Oceania. Sculptors have long

used stone for outdoor statues and

monuments because it resists damage by

rain and wind. Popular types of stone

for sculpture include marble, alabaster,

granite, sandstone, limestone, and semiprecious

stones.

Modern sculptors use these traditional

materials as well as many others, including

plastics, fabrics, fiberglass, neon

tubes, and even garbage. Today, concrete

is often used for large outdoor projects.

This is because it is cheap, hard, and

long-lasting.

Processes

The most common ways to form sculpture

are carving, modeling, casting, and

constructing. Carving is the process of

turning such substances as stone, wood,

or ivory into a desired shape by cutting

or chipping away pieces. Modeling

involves shaping a soft material such as

clay by hand. It can then be baked until

A stone sculpture of an angel

stands on a bridge in Rome, Italy.

A woman sculpts a bust, or a figure of a

person’s head and shoulders, from clay.

BRITANNICA STUDENT ENCYCLOPEDIA Sculpture 55

it hardens. Models can also be used in

casting.

Casting is used to reproduce a piece of

sculpture through the use of a mold. In

one version a plaster mold is made

around a model. When the mold has

hardened, it is split apart and taken off

the model. The mold is then put back

together, with a hollow space where the

model was. A mixture of plaster and

water is poured into the mold and left to

dry. When the mold is chipped away, a

perfect copy of the original model

remains. A method of casting with wax

is commonly used for metal sculptures.

This process can be used to create many

copies of a statue.

Modern sculptors sometimes construct

sculpture out of assorted materials. They

may use such techniques as welding,

screwing, nailing, or gluing to combine

different pieces of material.

History

Early Sculpture

Sculpture from prehistoric times has

been found around the world. The earliest

sculptures are made of such naturally

occurring materials as clay, stone, and

ivory. Beginning in about 3000 BC,

people also began to make sculptures of

bronze and other metals.

In early civilizations sculpture was associated

largely with religion. In the

Middle Eastern region of Mesopotamia

almost all early sculpture was used in

temples. People in ancient Egypt created

huge sculptures of their kings and gods,

emphasizing their power. They also

made many statues and reliefs for use in

tombs.

In ancient Greece sculpture reached its

high point in the 400s BC. The Greeks

of this period aimed to show humans

and gods in their most perfect forms.

Most of their statues appear calm in

expression and pose. The ancient

Romans later made many copies of

Greek sculpture. In this way they preserved

the Greek tradition for later generations.

From about AD 200 the new religion of

Christianity began inspiring artists to

create works that reflected Christian

figures and events. During the Middle

Ages (from about 500 to 1500), much

European sculpture was closely related

to church architecture.

Sculpture in India has also centered on

religion. The Gupta period, lasting from

about the 300s to the 500s, produced

some of the best examples of Buddhist

sculpture.

Renaissance, Baroque, and

Neoclassicism

The period in Europe called the Renaissance

(mid-1300s through the 1500s)

was a time of outstanding artistic

achievement. Renaissance artists were

inspired by the classical styles of ancient

Greece and Rome. The Renaissance

began in Italy. The Italian artists Donatello

and Michelangelo were among the

finest sculptors of the period.

Sculptures

sometimes are

painted or

polished. This

helps to protect

them from

the weather

and makes

them more

decorative.

56 Sculpture BRITANNICA STUDENT ENCYCLOPEDIA

In the 1600s baroque became a major

style ofWestern art. Baroque sculpture is

dramatic and highly decorative. It

appeals to the senses and emotions. The

leading baroque sculptor was the Italian

artist Gian Lorenzo Bernini.

The neoclassical (meaning “new classical”)

style was popular in Europe in the

1700s. As in the Renaissance, sculptors

in this period sought to revive ancient

Greek and Roman ideals of beauty. A

leading sculptor of this style in Italy was

Antonio Canova.

Modern Sculpture

In the late 1800s the French sculptor

Auguste Rodin challenged centuries of

tradition. He showed the human figure

expressing tension and fleeting emotions.

He also sometimes used textured

surfaces that heighten the sense of life

and movement. In these ways Rodin’s

sculpture differs from the cold, impersonal

smoothness of the classical tradition.

With their strong sense of power

and drama, his works greatly influenced

sculptors of his own time as well as of

the modern era.

In the 1900s and beyond, sculptors

experimented with form and materials.

Sculptors such as Constantin Brancusi,

Henry Moore, Barbara Hepworth, and

Raymond Duchamp-Villon created

works of abstract sculpture—sculpture

that does not try to realistically

represent anything in the visible world.

Instead, these sculptors focused on the

shapes and forms themselves. Some

sculptors used objects found in the

everyday world to make viewers see the

objects in a different light. Their aim

was not to please the eyes but to make

the viewer think about what art is and

can be.

#More to explore

Arts • Drawing • Michelangelo

• Painting • Pottery

Sea Anemone

Sea anemones look like flowers but are

actually animals. Their “petals” are armlike

body parts called tentacles, which

circle the mouth. The tentacles may be

An abstract sculpture by Barbara Hepworth

is on display at a sculpture garden at the

University of California, Los Angeles.

The jewel anemone is a kind of sea anemone.

BRITANNICA STUDENT ENCYCLOPEDIA Sea Anemone 57

red, yellow, green, blue, orange, brown,

white, or a mixture of colors. Sea

anemones use their tentacles to sting the

shrimps, fish, and other small animals

that they eat.

There are more than 1,000 species, or

kinds, of sea anemone. They live in

oceans throughout the world.

Sea anemones are invertebrates, which

means they do not have a backbone.

They have soft bodies that may be thick

and short or long and slender. Most of

the body is made up of water. Sea

anemones range from less than an inch

(2.5 centimeters) to about 5 feet (1.5

meters) across.

Most sea anemones rarely move. Some

glide very slowly or do slow somersaults.

Sea anemones are usually found attached

to a hard surface such as a rock, a seashell,

or the back of a crab. A flattened

disk attaches the animal to an object by

suction. Some sea anemones float near

the ocean’s surface or burrow deep into

sand or mud.

Sea anemones are related to jellyfish.

Like a jellyfish, a sea anemone can sting

a person who touches it. The sting can

cause pain or sickness.

#More to explore

Jellyfish • Ocean

Sea Horse

A sea horse is an unusual fish with a

horselike head. There are more than 20

species, or types, of sea horse. They live

in warm and mild seas.

Sea horses are small fish. They are about

1 to 12 inches (4 to 30 centimeters)

long. Instead of scales, a sea horse has

bony rings covering its body. Sea horses

can be bright yellow or orange, or they

can be brown or black. Some are striped

or speckled. They often blend in with

nearby plants.

A sea horse usually spends its life in one

small area near the shore. It wraps its

curled tail around seaweed or coral to

keep from being swept out to sea. Sea

horses swim in an upright position.

They are weak swimmers.

Sea horses feed constantly. They eat tiny

creatures such as brine shrimp. A sea

horse sucks food into its tiny mouth

through its snout.

In some countries

people

eat sea

anemones.

Cooking the

sea anemone

gets rid of the

poison.

A sea horse uses its tail to

anchor itself to undersea plant

life.

58 Sea Horse BRITANNICA STUDENT ENCYCLOPEDIA

Sea horses are unusual in the way they

reproduce. The female lays her eggs in a

pouch beneath the male’s tail. The male

carries the eggs until they hatch. The

baby sea horses look like small adults.

Many people like sea horses because of

their interesting appearance. Some

people keep sea horses in aquariums. In

some places people use sea horses in

medicine.

#More to explore

Fish

Seal

Seals are mammals that live mostly in

cold seas. They are related to the walrus.

There are more than 30 species, or

kinds, of seal. They can be divided into

two groups: earless, or true, seals and

eared seals. Earless seals actually do have

ears, but they do not stick out. Eared

seals have visible ears. Sea lions are eared

seals with a thick, hairy neck that looks

like a lion’s mane.

Seals are found throughout the world.

They are especially plentiful in seas near

the North and South poles. Some species

like the open ocean. Others prefer

to live along the coast. All seals spend

some time on islands, beaches, or sheets

of ice. They come ashore to breed.

A seal’s body is round in the middle and

narrower at the ends. The skin is usually

brown, gray, or black. The smallest seals

are about 4 feet (1.2 meters) long and

weigh about 200 pounds (90 kilograms).

The largest seals can be 21 feet (6.5

meters) long and weigh more than

8,000 pounds (3,600 kilograms). They

are called elephant seals.

Instead of legs, seals have two pairs of

flippers. Flippers help seals to swim.

Eared seals can turn their rear flippers

forward under the body. This allows

The ears of true seals do not stick out. them to scoot around while on land.

Sea lions are seals with visible ears. Sea

lions can turn their rear flippers forward to

help them to move on land.

BRITANNICA STUDENT ENCYCLOPEDIA Seal 59

Earless seals cannot turn their rear flippers

forward. They move on land by

wriggling on their bellies. They also may

pull themselves forward with their front

flippers.

Seals eat mostly fish. Some also eat squid

and shellfish. The leopard seal of the

Antarctic feeds on penguins and other

seals.

#More to explore

Mammal •Walrus

Sea Serpent

#see Animals, Legendary.

Sea Snake

Sea snakes are snakes that spend most of

their lives in water. They usually swim in

groups. From far away, a group can look

like one long snake. For this reason, sea

snakes may have inspired legends about

giant sea serpents.

Sea snakes belong to the same family as

cobras. There are about 50 species, or

types, of sea snake. Most are found in

Asia, Australia, and the Pacific Islands.

Sea snakes live in warm, coastal waters.

They can also be found in rivers, lakes,

and swamps. Only the yellow-bellied sea

snake swims hundreds of miles out into

the ocean. This sea snake is also the only

known reptile that spends its entire life

in water.

Most sea snakes are 3 to 5 feet (0.9 to

1.5 meters) long. Many have lightcolored

bodies with dark rings. Sea

snakes have short, hollow fangs that

contain venom, or poison. This venom

attacks the nervous system (nerves and

brain) and can be deadly. Sea snakes eat

eels, fish, and fish eggs.

Sea snakes are specially made for the

water. They have a flat tail that is shaped

like an oar. The snakes swim by moving

the tail from side to side. Their lungs

can also hold extra oxygen. This allows

them to stay underwater for long periods.

Some sea snakes have very small

belly scales. These scales make them

unable to crawl on land.

#More to explore

Cobra • Snake

Season

As a year passes, regular changes occur

in the weather. This cycle of weather

The banded sea krait is a sea snake of the

Pacific Ocean.

60 Sea Serpent BRITANNICA STUDENT ENCYCLOPEDIA

The North and South poles are the farthest

points from the equator. Therefore

temperatures stay cold throughout the

year. During the winter it is dark even in

the daytime. In the summer the sun

shines late at night. However, this “midnight

sun” is not strong enough to give

the poles hot weather.

Between the poles and the equator, temperatures

may vary greatly from one

season to the next. During winter, the

weather is generally cold and often

snowy. Some animals hibernate, or sleep

for a long time. Many birds have

migrated, or moved to warmer places for

the season. Some plants die, and others

stop growing.

When spring arrives temperatures

become warmer. Plants and trees produce

new leaves and flowers. Birds

return from their winter homes, and

animals come out of hibernation.

During the summer, temperatures reach

their highest levels. There are more

hours of daylight, and the sun is more

intense. This extra sunshine helps plants

to grow.

Temperatures fall again as autumn

begins. Some trees and plants lose their

leaves. Animals with fur grow thicker

coats to keep them warm during the

coming winter. Many birds travel to

warmer places.

#More to explore

Earth • Equator • Hemisphere

•Weather

Seed

Most plants begin life as seeds. Plants

form their seeds inside flowers or cones.

In flowering plants a fruit often surrounds

the seeds.

Seeds need the right conditions to germinate,

or grow into a new plant. They

need air, water, the right temperature,

good soil conditions, and the right

amount of light.

Features

A seed contains a miniature plant, called

an embryo, that can develop into a fully

grown plant. The outer shell of a seed,

called a seed coat, protects the embryo.

Inside the seed a nutritious material

provides food to the embryo. In flowering

plants this material is called

endosperm.

Germination

Once a seed has formed, it leaves its

parent plant. Seeds often can stay

dormant, or inactive, for many years

before they germinate, or grow. Because

of this, people can store seeds and plant

them later. A seed will germinate once

it is in the ground and the conditions

are right.

As germination begins, parts of the

embryo break out of the seed coat. One

part grows downward. It becomes the

plant’s roots, which take in water and

food from the soil. Other parts grow

upward. They become the plant’s stem

and leaves, which absorb sunlight.

Winter is an

old Germanic

word meaning

“time of

water”—of

rain and

snow.

62 Seed BRITANNICA STUDENT ENCYCLOPEDIA

How Seeds Travel

It is important that seeds travel away

from their parent plant. If the seeds land

nearby, they compete with the parent for

light and water. This means that they are

less likely to survive.

Seeds travel in many ways. Some plants

have fruits or pods that burst open to

scatter the seeds inside. The wind blows

lightweight seeds. Some seeds, such as

those of dandelions, have fluffy parts

that help them to drift through the air.

Some plants, such as coconut palms,

drop their seeds in nearby water. These

seeds have waterproof coverings that let

them float far away.

Animals also carry seeds to other places.

Seeds with sticky or prickly seed coats

stick in the fur of animals. The seeds

drop to the ground later. When birds

and other animals eat fruit, the seeds

pass through their bodies and often end

up far from where they ate the fruit.

Uses

Seeds are an important source of food

for people and animals. Seeds used for

food are often called grains or beans.

People also use seeds to make oils,

spices, fabric dye, and jewelry.

#More to explore

Bean • Flower • Fruit • Grain • Plant

Seminole

The Seminole are Native Americans

who were once part of the Creek tribe of

the U.S. state of Georgia. In the 1700s

they broke away from the Creek and

moved southward into northern Florida.

The name Seminole probably came

from the Spanish word cimarron, which

means “wild” or “runaway.”

BRITANNICA STUDENT ENCYCLOPEDIA Seminole 63

The Seminole lived in villages. A chief

ruled each village. The Seminole made

their homes by covering wooden frames

with roofs of branches, grass, and bark.

They grew corn, squash, beans, and

pumpkins. They also hunted, fished,

and gathered wild plants.

After the Seminole reached Florida, they

were joined by runaway slaves from

Georgia. In 1817–18 U.S. troops tried

to recapture the slaves by attacking

Seminole towns. This conflict became

known as the First SeminoleWar.

In 1832 the U.S. government tried to

get the Seminole to move to Indian Territory

(now Oklahoma). Most refused.

From 1835 to 1842 they fought U.S.

troops in the Second SeminoleWar.

After the war most Seminole moved to

Indian Territory.

A few hundred Seminole were able to

stay in Florida by hiding in the swamplands.

In the 1850s U.S. troops tried to

force them out. That conflict was called

the Third SeminoleWar.

At the end of the 20th century there

were about 12,000 Seminole. Most lived

in Oklahoma or Florida.

#More to explore

Creek • Native Americans

Sendak, Maurice

Maurice Sendak is a U.S. artist and children’s

author. Many of his picture stories

blend true-life situations with

imaginary scenes. He is best known for

his 1963 book titled Where theWild

Things Are.

Maurice Bernard Sendak was born on

June 10, 1928, in New York City. As a

child Maurice drew pictures and wrote

A photograph taken in the 1920s shows a

group of Seminole wearing traditional

clothing. They are standing in front of their

houses.

Maurice Sendak stands among enlargements

of the pictures he drew for Where the

Wild Things Are.

64 Sendak, Maurice BRITANNICA STUDENT ENCYCLOPEDIA

stories. After high school he trained at

an art school in New York City.

The first children’s books Sendak illustrated

were Marcel Ayme’s TheWonderful

Farm (1951) and Ruth Krauss’s A

Hole Is to Dig (1952). Sendak went on

to illustrate more than 80 children’s

books by a number of different authors.

In the mid-1950s Sendak began writing

and illustrating his own books. In 1963

Sendak published Where theWild Things

Are, which made him famous. In 1964

Sendak earned the Caldecott Medal for

his illustrations for the book.

In the 1970s Sendak turned his talents

to television and theater. He created

opera versions of some of his stories, and

he designed sets for the stage. Sendak

also continued producing children’s

books into the 1990s.

#More to explore

Literature for Children

Seneca

The Seneca were the largest of the five

Native American tribes that formed the

Iroquois Confederacy. The tribes of the

confederacy lived in what is now the

U.S. state of New York. They all spoke

similar languages. The Seneca traditionally

lived in western New York.

Like the other Iroquois, the Seneca lived

in longhouses. Longhouses were large,

rectangular homes made of a wooden

frame covered with bark. For food, the

Seneca grew corn, beans, and squash.

They also fished and hunted.

In the 1600s European traders began

arriving in Seneca territory. The Seneca

traded furs with them for guns and

metal tools. During the American

Revolution (1775–83) the Seneca sided

with the British. After the Americans

won the war, the Seneca lost much of

their land. A small group of Seneca fled

to Canada, but most stayed in New

York. In 1817 some Seneca settled in

Ohio. In 1831 they gave up this land in

return for land in Indian Territory (now

Oklahoma).

At the end of the 20th century there

were about 9,000 Seneca in the United

States. Most lived in New York and

Oklahoma. Another 1,000 lived in

Canada, mainly in Ontario.

#More to explore

Iroquois • Native Americans

Cornplanter was a chief of the Seneca in

the 1700s.

BRITANNICA STUDENT ENCYCLOPEDIA Seneca 65

Senegal

The country of Senegal sits on the west

coast of Africa. Senegal has produced

several famous writers, including

Leopold Senghor, the country’s first

president. Dakar is the capital and largest

city.

Geography

The Atlantic Ocean forms Senegal’s

western border. Senegal shares land borders

with Mauritania, Mali, Guinea,

Guinea-Bissau, and The Gambia. The

Gambia extends into Senegal from the

coast. The small part of Senegal south of

The Gambia is called the Casamance

region.

Most of the land is flat and low. In the

west are small plateaus, or areas of flat,

raised land. Low mountains rise in the

east. Senegal has four major rivers: the

Senegal, the Saloum, the Casamance,

and the Gambia. Most of the country is

hot year-round. The south gets more

rain than the north.

Plants and Animals

Grasses and scattered trees grow in

much of Senegal. Forests are thicker in

the south. Mangrove trees grow along

the southern coast.

Senegal’s animals include monkeys,

panthers, warthogs, and wild dogs.

Some chimpanzees, elephants,

hippopotamuses, antelope, lions, and

leopards live in a national park in the

southeast.

People

Senegal has several large ethnic groups,

including the Wolof, the Fulani, the

Serer, the Tukulor, the Diola, the

Malinke, and the Soninke. TheWolof

are the largest group. French is the

national language, but most people

speak the language of their group. Most

of the people follow the religion of

Baobab trees grow in a grassy area of

Senegal.

66 Senegal BRITANNICA STUDENT ENCYCLOPEDIA

Islam. More than half of the population

lives in the countryside.

Economy

Most of Senegal’s people work in agriculture.

Peanuts are a major crop. Other

important crops include rice, sugarcane,

millet, watermelons, cotton, and vegetables.

Senegal sells a lot of fish to other

countries.

Senegal’s industries produce peanut oil,

ships, fertilizers, and petroleum products.

Senegal also mines salt and phosphates,

which are used to make

fertilizers. Tourism, communications,

and other services have become important

parts of the economy.

History

Humans have lived on the land that is

now Senegal since prehistoric times. The

Tukulor people settled in the area almost

a thousand years ago. At about the same

time Berbers from the north began

spreading Islam throughout the region.

TheWolof, the Serer, and other peoples

later developed kingdoms.

European Trade

European explorers reached the area in

the 1400s. The first to arrive were the

Portuguese. The Dutch, the English,

and the French came later. The Europeans

set up trading posts along the coast

beginning in the 1600s. They traded

African slaves, ivory, gold, and a useful

plant material called gum.

French Rule

In 1895 Senegal became a part of the

large French colony of French West

Africa. In 1958 Senegal became a

separate state within the French

Community, a group of countries with

ties to France. Senegal soon left the

community, however, and formed a

union with Mali. In 1960 Senegal

separated from Mali to become an

independent country.

Independent Senegal

Leopold Senghor became Senegal’s first

president. He was a poet who had led

the movement for independence. In

1982 Senegal and The Gambia formed a

union called Senegambia. The union

broke apart in 1989. Meanwhile rebels

in the Casamance region began fighting

Senegal for independence. The rebels

and Senegal’s government signed a peace

agreement in 2004.

..More to explore

Dakar • Gambia, The

Peanuts are piled high on a truck

near Fatick, Senegal.

Facts About

SENEGAL

Population

(2008 estimate)

12,688,000

Area

75,955 sq mi

(196,722 sq km)

Capital

Dakar

Form of

government

Republic

Major cities

Dakar, Thies,

Kaolack, Saint-

Louis, Mbour,

Ziguinchor

BRITANNICA STUDENT ENCYCLOPEDIA Senegal 67

Senses

The senses help humans and other animals

react to changes in their surroundings

and inside their bodies. Animals

receive sensory information all the time.

They see a bug dart across a pond. They

hear the roar of a lion. They smell a rose.

They taste fresh bread. They touch a

jagged piece of ice. They get dizzy from

spinning in a circle.

After the body takes in sensory information,

sense cells send the information to

the brain. Sense cells are also called

receptors. The information travels from

receptors to the brain through nerves.

The brain thinks about the information

and then makes the body react to it.

The five basic senses are sight, hearing,

smell, taste, and touch. The eyes sense

sight. The ears sense sounds. The skin

senses touch. On the tongue, taste

receptors are found in structures called

taste buds. They identify sweet, salty,

sour, bitter, and meaty tastes. The nose

detects smells. The receptors in the nose

also help with the sense of taste.

Humans use their skin, eyes, nose, tongue,

and ears to sense information in the world

around them.

Different animals have special body parts to

sense sound, movement, heat, touch, and

other information.

68 Senses BRITANNICA STUDENT ENCYCLOPEDIA

In addition to the five basic senses,

nearly all animals sense motion, heat,

cold, pressure, pain, and balance. The

sense of motion—knowing where the

arms and legs are and where to move

them—is called kinesthesis. The sense of

balance, or equilibrium, is controlled by

structures in the inner ear. These structures

help keep the body in balance and

prevent falls.

..More to explore

Ear • Eye • Nervous System • Nose

• Skin • Tongue

Seoul

Population

(2008 estimate)

10,421,780

Seoul is the capital of South Korea, a

country in eastern Asia. Before 1948

South Korea and North Korea were one

country. For hundreds of years during

that period Seoul was the capital of all of

Korea. The city’s name itself has come to

mean “capital” in the Korean language.

Seoul is one of the largest cities in the

world. It is also South Korea’s center of

culture, education, business, and industry.

It lies on the Han River.

The economy of Seoul is very important

to South Korea. Many of the country’s

banks and insurance companies have

their headquarters in the city. Factories

in Seoul make clothing, machinery, electronics,

processed foods, and other products.

Printing is another leading

industry.

People have lived in the Seoul area for

thousands of years. A royal summer palace

was built at the site in 1068. After

that a large settlement was established

there.

In 1394 the Choson rulers of Korea

made Seoul the capital. The Choson

ruled Korea until 1910. Japan controlled

Korea from 1910 to 1945. Seoul

remained the capital under Japanese

rule. During that time Seoul was called

Kyongsong.

Seoul was damaged during the Korean

War (1950–53). Afterwards it was rebuilt

and expanded greatly. The modern city

Kyongbok Palace was built in Seoul in

1394. Most of the original buildings on the

grounds were destroyed in invasions and

wars. Some buildings have been rebuilt.

BRITANNICA STUDENT ENCYCLOPEDIA Seoul 69

has many skyscrapers and an extensive

transportation system. The city hosted

the SummerOlympic Games in 1988.

#More to explore

Korea, North • Korea, South • Korean

War

Sequoia

The term sequoia refers to two different

North American trees: the giant sequoia,

also called the big tree, and the redwood.

Both trees were named in honor

of Sequoyah, a distinguished Native

American of the Cherokee people.

#More to explore

Giant Sequoia • Redwood

Sequoyah

Sequoyah was an important member of

the Cherokee group of Native Americans.

He invented a system of writing so

his people could read and write in their

own language.

Sequoyah was born in about 1760 or

1770 in what is now Tennessee. He was

probably the son of a British trader and

a Cherokee woman. Sequoyah was

raised by his mother and became a talented

artist. From 1813 to 1814 he

fought for the U.S. Army in the Creek

War. This was a war between the U.S.

government and the Creek Native

Americans.

In about 1809 Sequoyah began working

on a system of writing. The Cherokee

people had their own spoken language,

but they did not have a way to write in

it. Sequoyah hoped that a written language

would help the Cherokee to stay

independent from white settlers.

Sequoyah used symbols to stand for each

syllable used in the Cherokee language.

(A syllable is a unit of sound.) His

daughter helped him to pick out all the

syllables in the Cherokee language. By

1821 he had created a system of 86 symbols

that stood for all the Cherokee

syllables.

Sequoyah’s system, called a syllabary,

soon became popular with other Cherokee.

It was easy to use. The Cherokee

began to teach it in their schools. They

also published books and newspapers in

their own language.

Sequoyah’s people honored him for his

accomplishments. He died in 1843.

#More to explore

Cherokee • Native Americans •Writing

Sequoyah invented a system for reading

and writing the Cherokee language.

Sequoyah

used letters

from the

English,

Greek, and

Hebrew

alphabets to

create his

Cherokee

symbols.

70 Sequoia BRITANNICA STUDENT ENCYCLOPEDIA

Serbia

Serbia is a country in southeastern

Europe. It was a republic, or state, of the

country of Yugoslavia for much of the

1900s. In the 1990s all of Yugoslavia’s

republics except Serbia and Montenegro

became independent countries. In 2006

Serbia and Montenegro each became

independent countries as well. The capital

of Serbia is Belgrade.

Geography

Serbia is in the Balkan region of Europe.

It shares borders with Kosovo and the

countries of Montenegro, Bosnia and

Herzegovina, Croatia, Hungary,

Romania, Bulgaria, and Macedonia.

The Danube River flows through the

northern part of the country, which is

flat. The area south of the Danube is

mainly mountainous. Most of the country

has cold winters and warm summers.

Plants and Animals

Forests of oak and beech trees grow in

the lower areas. Pine and fir trees grow

in the mountains. The country’s animals

include deer, foxes, wolves, wild pigs,

bears, and many types of birds.

People

Serbs make up most of the population.

Small groups of Hungarians, Croats,

Bosniacs (Bosnian Muslims), Roma

(Gypsies), Montenegrins, and others

also live in the country.

Most Serbs are Eastern Orthodox Christians.

They speak Serbo-Croatian. About

half of the people live in cities or towns.

Economy

Manufacturing is an important part of

the economy. Factories make machinery,

metals, chemicals, food products, electronics,

cloth, cars, trucks, and other

goods. The mining industry produces

aluminum, copper, and lead.

Agriculture is also important. The major

crops are corn, sugar beets, wheat, and

potatoes. Farmers also grow grapes to

make wine. Pigs, sheep, and cattle are

the main livestock.

History

People have lived in the Balkan region

for thousands of years. Slavic peoples,

including the Serbs, settled in the area

by the 600s. The Ottoman Empire con-

BRITANNICA STUDENT ENCYCLOPEDIA Serbia 71

quered the Serbs in 1389. Serbia gained

independence in the 1800s.

In 1914 a Serb assassinated Francis Ferdinand,

the archduke (prince) of Austria.

In response, Austria declared war on

Serbia. This conflict turned into World

War I.

Yugoslavia

After the war, in 1918, Serbia joined

with Montenegro, Croatia, Slovenia,

Macedonia, and Bosnia and Herzegovina

to form a new country called the

Kingdom of Serbs, Croats, and Slovenes.

In 1929 the country was renamed Yugoslavia.

Communists took control of Yugoslavia

afterWorldWar II ended in 1945.

Yugoslavia had a strict Communist government

until the late 1980s.

CivilWar and Beyond

In 1991 and 1992 four of Yugoslavia’s

republics declared independence. Serbia

wanted to keep Yugoslavia together. The

republics fought a civil war until 1995.

At the end of the war the republics of

Croatia, Slovenia, Macedonia, and Bosnia

and Herzegovina were independent

countries. Only Serbia and Montenegro

remained in Yugoslavia.

After the war Albanians in the Serbian

province of Kosovo also began fighting

for independence. In response, Serbs

attacked many Albanian villages. The

fighting ended in 1999, but problems

continued between Yugoslavia’s Albanians

and Serbs. The United Nations

temporarily took over the government of

Kosovo.

In 2003 the republics of Serbia and

Montenegro formed a new union that

gave each republic more independence.

Montenegro broke away from the union

in 2006. In 2008 Kosovo declared independence

from Serbia. Other countries

supported the move, but Serbia refused

to recognize Kosovo as a separate country.

..More to explore

Balkan Peninsula • Belgrade

• Communism • Kosovo • Montenegro

• Yugoslavia

Boats travel on the picturesque Danube

River in Belgrade, Serbia.

Farmers grow corn on a hillside in Serbia.

Facts About

SERBIA

Population

(2008 estimate)

7,352,000

Area

29,922 sq mi

(77,498 sq km)

Capital

Belgrade

Form of

government

Republic

Major cities

Belgrade, Novi

Sad, Nis,

Kragujevac

72 Serbia BRITANNICA STUDENT ENCYCLOPEDIA

Serra, Junipero

Junipero Serra was a Spanish priest. In

1769 he founded the first mission

(Christian community) in California at

the Spanish settlement of San Diego.

The Spanish established missions in

North America to spread Christianity to

Native Americans.

Serra was born on the Spanish island of

Majorca on November 24, 1713. He

became a priest in the Roman Catholic

church. In 1750 he arrived in Mexico

City to work as a missionary. He worked

there until 1767, when he was sent to

California to start missions there.

From 1770 to 1782 Serra founded eight

more Californian missions. He died in

Carmel, California, on August 28, 1784.

#More to explore

Missions, Spanish

Seuss, Dr.

The author Theodor Seuss Geisel is better

known to readers as Dr. Seuss. He

wrote nearly 50 books for children. His

stories are famous for their nonsense

words, wild rhymes, and amusing drawings

of unusual creatures.

Geisel was born on March 2, 1904, in

Springfield, Massachusetts. He

graduated from Dartmouth College in

New Hampshire in 1925. Then he

studied at Oxford University in

England and the Sorbonne, a college in

France. After that he worked as an

illustrator and cartoonist.

During and afterWorldWar II (1939–

45) Geisel served in a part of the U.S.

Army that made informational films.

Two films he made during the war won

Academy awards.

Geisel’s first children’s book, And to

Think That I Saw It on Mulberry Street,

was published in 1937. He wrote it

under the name Dr. Seuss. His most

famous books include Horton Hears a

Who (1954), How the Grinch Stole

Christmas (1957), The Cat in the Hat

(1957), Green Eggs and Ham (1960), The

Lorax (1971), and Oh, the Places You’ll

Go! (1990). Geisel both wrote the stories

and drew the pictures for his books.

In the late 1950s Geisel started a

company called Beginner Books, which

produced books for children. Geisel

died on September 24, 1991, in La

Jolla, California.

#More to explore

Literature for Children

Dr. Seuss poses with a Cat in the Hat toy.

BRITANNICA STUDENT ENCYCLOPEDIA Seuss, Dr. 73

Seychelles

The country of Seychelles is a scattered

group of islands in the western Indian

Ocean. The capital, Victoria, is on the

largest island, Mahe.

Geography

Seychelles lies about 1,000 miles (1,600

kilometers) east of Africa. It includes

more than 100 islands divided into two

groups: the Mahe group and the coralline

group. The Mahe islands are rocky

and mountainous. The coralline islands

are flat and made of coral.

Plants and Animals

Seychelles is home to the rare coco de

mer, or double coconut tree. Avocados,

breadfruit, bananas, mangoes, papayas,

and pineapples also grow on the islands.

Animals include green sea turtles, giant

tortoises, and many types of bird.

People

Most of the people are Seychellois Creole.

They have a mixture of Asian, African,

and European ancestors. The most

common language is Creole. Creole is a

mixture of French, English, and African

languages. Roman Catholicism is the

main religion. Most Seychellois live in

cities or towns, mainly on Mahe Island.

Economy

Tourism is a major source of money for

Seychelles. Fishing is another important

part of the economy. The country’s

main product is canned tuna. Farmers

grow coconuts, cinnamon, bananas, and

tea. They also raise pigs and chickens.

History

No one lived on the islands until the

1700s, when French settlers arrived with

their African slaves. In 1814, after losing

a war, France gave the islands to Great

Britain. Seychelles gained independence

from Britain in 1976.

..More to explore

Indian Ocean • Victoria

Seychelles is known for its fine beaches.

Facts About

SEYCHELLES

Population

(2008 estimate)

85,500

Area

176 sq mi (455

sq km)

Capital

Victoria

Form of

government

Republic

Major city

Victoria

74 Seychelles BRITANNICA STUDENT ENCYCLOPEDIA

Shakespeare,

William

William Shakespeare is often praised as

the world’s greatest playwright. Though

he lived 400 years ago, his plays are still

studied and enjoyed today.

Early Life

William Shakespeare was born in 1564

in the town of Stratford-upon-Avon,

England. He had three younger brothers

and two younger sisters. His father was a

glove maker who later became the

mayor of Stratford.

When Shakespeare was 18, he married

Anne Hathaway. What Shakespeare did

to support his young family is unknown.

Some scholars think that he was a

schoolteacher. Others think that he traveled

with a group of actors.

Career in the Theater

By 1592 Shakespeare was working as a

writer and actor in London. In that year

a disease called the black plague devastated

the city. Officials closed the theaters

and other public places to stop its

spread. Shakespeare then turned to writing

poetry.

London’s theaters reopened in 1594. By

then Shakespeare had joined an acting

group called Lord Chamberlain’s Men.

They often presented plays for royalty.

Along with acting and writing, Shakespeare

also was involved with the business

side of theater. He became wealthy.

Plays

Shakespeare wrote 37 plays in 20 years.

His plays generally fall into three

categories: tragedies, comedies, and

histories. Tragedies are plays that

describe the downfall of the main

character. Shakespeare’s most famous

tragedies include Hamlet, King Lear,

and Macbeth. Comedies are humorous

plays that end happily. Shakespeare’s

comedies include A Midsummer Night’s

Dream, As You Like It, and The Taming

of the Shrew. Shakespeare’s histories are

dramas about some of England’s

powerful kings, including Henry IV

and Richard II.

Later Years

Shakespeare retired from the theater in

about 1610. He returned to his hometown

of Stratford-upon-Avon. He died

there on April 23, 1616.

#More to explore

Drama • Poetry

A collection of William Shakespeare’s

poems, printed in 1640, included a picture

of the author.

BRITANNICA STUDENT ENCYCLOPEDIA Shakespeare, William 75

Shamrock

A shamrock is a plant whose small,

green leaves are divided into three heartshaped

parts called leaflets. Shamrocks

are a symbol of Ireland, especially on

Saint Patrick’s Day.

Several different plants are known as

shamrocks. They include some members

of the pea family: white clover, small

hop or suckling clover, and black medic.

Wood sorrel is another plant called a

shamrock. The plants all grow in the

temperate, or mild, regions of the

Northern Hemisphere. Experts disagree

on which plant, if any, is the true Irish

shamrock.

In rare cases a shamrock leaf has four

leaflets instead of three. Finding a shamrock

with four leaflets supposedly brings

good luck.

#More to explore

Pea • Saint Patrick’s Day

Shark

Sharks are fast-swimming fish that have

a skeleton made of cartilage instead of

bone. (Cartilage is an elastic tissue that

is created before bone begins to form.)

They are related to rays. Sharks are

among the oldest animals on Earth. The

first sharks lived more than 300 million

years ago. Today there are more than

300 species, or types, of shark.

Where Sharks Live

Most sharks live in oceans in the mild or

warm parts of Earth. But the Greenland

shark lives in the cold Arctic waters.

Sand sharks spend most of their time at

the bottom of shallow water. The Portuguese

shark lives in the deepest parts of

the ocean.

Physical Features

The whale shark is the largest living fish.

It can reach about 50 feet (15 meters)

long and weigh nearly 20 tons. The

smallest shark is the dwarf lantern shark,

which is only about 7.5 inches (19 centimeters)

long.

Several different plants that have three-part

leaves are sometimes called shamrocks. The

redwood sorrel is one such plant. It grows

in the redwood forests of western North

America.

Sharks move restlessly to keep from sinking

to the ocean floor.

76 Shamrock BRITANNICA STUDENT ENCYCLOPEDIA

Most sharks have a pointed snout that

extends forward over the mouth.

However, hammerhead sharks have a

wide, flat head. A shark’s teeth are

sharp and triangular and grow

throughout its life. Only a few species,

including the white shark, the tiger

shark, and mako sharks, have very large

teeth. Sharks have a muscular, upturned

tail and pointed fins.

Sharks normally have tough, gray skin

with toothlike scales. Their skin also

may be cream, yellow, brown, bronze,

blue, or nearly black in color. They often

are patterned with spots, bands, or marbling.

Behavior

Sharks use their sharp sense of smell to

find food. They may eat plankton, shellfish,

sea turtles, fish, seals, porpoises,

squid, or whales. Sharks circle their prey

and frequently approach from below.

When excited by the smell of blood,

sharks may have a “feeding frenzy.” This

means that they attack any object within

reach and feed rapidly.

Sharks swim constantly to keep from

sinking. They are known for their speed

in the water. Most species can swim 20

to 30 miles (32 to 48 kilometers) per

hour. But the speed of mako sharks has

been recorded at more than 60 miles (97

kilometers) per hour.

Most sharks live by themselves. But a

few, such as the spiny dogfish shark,

form schools, or groups.

Reproduction

Sharks reproduce in one of three ways.

In some types the female gives birth to

live young. In other types the young

hatch from eggs inside the female’s body

and then are born. In still other types

the female lays rectangular, leathery eggs

that become attached to rocks or seaweed.

The young hatch days or weeks

later. Female sharks may have from 2 to

about 20 young at a time.

Sharks and Humans

People eat the meat of some sharks,

including thresher and mako sharks.

Only some species—including the white

shark and the tiger shark—are considered

dangerous to humans. When these

sharks are hungry, disturbed, or defending

their territory, they may attack

humans. Even the movement and noises

of swimmers can cause some sharks to

attack. However, shark attacks are rare.

#More to explore

Fish • Ray

A hammerhead shark gets its name from its

wide, flat head.

BRITANNICA STUDENT ENCYCLOPEDIA Shark 77

Shawnee

The Shawnee are Native Americans who

traditionally lived over a large area in

what is now the eastern United States.

Their first known homeland was centered

in what is now Ohio.

During the summer the Shawnee lived

in wigwams.Wigwams were domeshaped

homes made from a frame of

wood poles covered with bark. The

women grew corn and other food crops.

The men hunted. During the winter the

Shawnee moved to hunting camps.

In the 1600s the Iroquois people drove

the Shawnee from their lands. The

Shawnee scattered. After 1725 many

Shawnee returned to Ohio.

The Shawnee fought repeatedly to

defend their lands against white settlers

who wanted to expand westward. In

1794 U.S. troops defeated the Shawnee

in the battle of Fallen Timbers. In 1795

Shawnee leaders signed a treaty in which

they gave up their Ohio lands.

Some Shawnee refused to leave the area.

Among them was Tecumseh, who organized

a confederacy (group) of tribes to

fight the Americans. Tecumseh died in

battle in 1813. His confederacy fell

apart soon afterward.

By the late 1800s most Shawnee had

settled in Indian Territory (now Oklahoma).

At the end of the 20th century

there were more than 6,000 Shawnee.

Most lived in Oklahoma.

#More to explore

Iroquois • Native Americans • Tecumseh

Sheep

Sheep are among the most valuable of all

domestic animals. Domestic animals are

ones that have been tamed for use by

humans. People eat sheep meat and

drink sheep milk. The animals’ wool is

used to make cloth. Male sheep are

called rams. Female sheep are called

ewes. Sheep are closely related to goats.

There are more than 200 breeds of

sheep. They are found on every continent

except Antarctica. Sheep can be

A Shawnee man wears a traditional headdress

and feathers.

A ewe watches over two lambs.

78 Shawnee BRITANNICA STUDENT ENCYCLOPEDIA

either wild or domestic. Most sheep like

to live in high and dry areas.

Adult sheep weigh 80 to 400 pounds

(35 to 180 kilograms). Some sheep have

horns. They curl in loops alongside the

head. Certain types of wild sheep have

very long horns. The horns of the bighorn

sheep can be more than 3.3 feet (1

meter) in length. Most domesticated

sheep grow a thick coat of fibers called

wool.Wild sheep grow both hair and

wool.

Sheep eat grass and plants. They often

graze in large groups, or flocks. Sheep

have four separate stomach compartments,

or sections. They regurgitate

their food (bring it back up from the

stomach) and chew it again. This helps

the stomach fully digest the food.

People raise sheep for their meat, milk,

and wool. The meat of an adult sheep is

called mutton. Meat from a younger

sheep is called lamb. Some people drink

sheep milk. It is also used to make

cheese. Certain types of sheep are raised

specifically for their wool. These include

Merino and Rambouillet sheep.

#More to explore

Goat

Shell

Every empty seashell on the beach once

contained an animal known as a mollusk.

Clams, oysters, scallops, conchs,

mussels, and snails are all types of mollusks.

The shells of these animals are

exoskeletons, or hard, outside skeletons

that protect their soft bodies.

Structure

All mollusk shells are made of a mineral

called calcium carbonate. To form a

shell, the mollusk’s body gives off substances

that contain calcium carbonate.

The substances harden into layers of

shell. As the animal grows, its shell also

gets bigger to make room for its body.

The Swaledale is an English

breed of sheep with curling horns.

Shells come in many shapes, colors, and

patterns.

BRITANNICA STUDENT ENCYCLOPEDIA Shell 79

Mollusk shells differ greatly in shape,

size, color, and texture. The way a shell

looks can help a mollusk avoid enemies.

Bright colors or patterns may scare away

enemies. Textures and colors that match

the surroundings help a mollusk to hide

from enemies.

Shells are also put together in various

ways. Snails and conchs have single

shells in the shape of a twisted cone.

These mollusks are called univalves.

Clams, oysters, scallops, and mussels

have shells with two halves joined on

one side. These mollusks are called

bivalves. Chitons have shells made of

eight overlapping plates.

Uses

The main purpose of a mollusk’s shell is

to protect its body. When in danger, a

mollusk can quickly pull its entire soft

body into the hard shell.

Shells have other purposes, too. Some

shells have ridges that keep the animal

anchored to the ocean floor. Other shells

are smooth, which allows the animal to

burrow easily into mud or sand. Shells

with long spines trap food.

Many people collect shells. They may

use them to make buttons and jewelry

and in other crafts. In the past, peoples

in Africa, North America, and the

Pacific islands used shells as money.

Other Types of Shells

Some animals other than mollusks also

have hard coverings called shells. Sea

animals from the crustacean family—for

example, crabs, lobsters, and shrimps—

have shells that do not grow. Turtles and

tortoises have shells made from bone.

The covering of an egg is also called a

shell. Eggshells protect developing birds

and reptiles until they hatch. The coverings

of many nuts and seeds are known

as shells, too.

#More to explore

Bivalve • Exoskeleton • Mollusk

Shinto

More than 100 million people follow a

system of religious beliefs and practices

known as Shinto. They are called Shintoists.

Most of them live in Japan.

The word Shinto means “the way of

kami.” Kami are superior powers that

Shintoists honor. They may be natural

objects and creatures (such as the spirits

About

100,000

different

shell-making

mollusks are

known to exist.

Strips of paper with prayers written

on them hang outside a

Shinto temple in Japan.

80 Shinto BRITANNICA STUDENT ENCYCLOPEDIA

of mountains and animals), worthy

human beings (such as emperors), or

gods and goddesses. Shintoists believe

that the kami are the source of human

life. The kami reveal truth to people and

guide them.

One of the most important kami is the

sun goddess, Amaterasu. Shintoists

believe that she was the ancestor of the

first emperor of Japan. A major Shinto

shrine, or place of worship, in the city of

Ise honors this goddess.

Shinto does not have a central book to

guide followers or regular weekly

services. Shintoists can visit shrines any

time they wish. Some people go every

day. Many Shintoists also practice

Buddhism. Some houses have both

Shinto and Buddhist altars set up for

prayer.

Festivals during the year bring

Shintoists together. There may be

cleansing rituals, food offerings, prayers,

music, and dance. Major celebrations

include a kind of thanksgiving and a

new year festival.

Little is known about Shinto’s origins. It

was already strong by the time Buddhism

came to Japan in the AD 500s.

The two religions mixed for hundreds of

years.

In the late 1800s the Japanese government

made Shinto the main religion of

Japan. It encouraged people to worship

at Shinto shrines. It made people believe

that the emperor of Japan was a god.

These efforts ended in 1945, after

Japan’s loss inWorldWar II.

#More to explore

Buddhism • Japan

Ship

A ship is a large boat that can carry passengers

or cargo for long distances over

water. People have been using ships for

transportation, exploration, and war

since ancient times.

Parts of a Ship

Most ships are much larger than most

boats, but they have many of the same

parts. As on boats, the front of a ship is

called the bow. The back is the stern. A

ship’s left side is known as the port side.

The right is the starboard side.

A ship’s frame, or body, is called the

hull. The keel is like the ship’s backbone.

It is a central beam that runs

along the bottom of the ship from front

A cargo ship loaded with freight containers

passes the Golden Gate Bridge near San

Francisco, in the U.S. state of California.

BRITANNICA STUDENT ENCYCLOPEDIA Ship 81

to back. The keel keeps the ship from

tipping over.

Ships usually have many decks. The

decks are like the floors of a building.

Cabins for passengers, engine and control

rooms, and spaces for cargo are

often on different decks.

An engine inside the ship provides

energy to propellers at the back of the

ship. The propellers push the ship

through the water. The rudder, which is

also at the back of the ship, helps in

steering. When the ship is not moving, a

heavy metal anchor may be lowered into

the water. This keeps the ship from

floating away.

Types and Uses of Ships

People use different types of ships for

many different purposes. Some of the

main types are trade ships, warships,

industrial ships, and pleasure vessels, or

cruise ships.

Trade ships carry different types of

cargo. Container ships carry cargo packaged

in large containers. General cargo

ships carry lumber, farm products, and

other goods that are hard to ship in containers.

Bulk ships carry coal, grains, and

other loose cargo. Tankers carry oil and

other liquid cargo. Refrigerated ships, or

reefers, carry meat, fish, and other products

that need to stay cold.

Navies use several different kinds of warships.

The largest are aircraft carriers. A

carrier has a large flat surface called a

flight deck that airplanes can use for

takeoffs and landings. Other types of

military ships include cruisers, destroyers,

and submarines. Submarines are

ships that can travel underwater.

Industrial ships are sometimes called

factory ships. Some industrial ships are

oil rigs. They have big machinery that

pumps oil from the ocean floor. Another

type of factory ship processes fish that

the crew catches at sea.

Many airplanes can be seen on the flight

deck of an aircraft carrier.

A cruise ship towers over pleasure

boats in a harbor.

82 Ship BRITANNICA STUDENT ENCYCLOPEDIA

Before airplanes made long-distance

travel quick and easy, people traveled in

ships called ocean liners. Ocean liners

had dining rooms and cabins where

guests could sleep. Today this type of

ship is called a cruise ship. Cruise ships

carry tourists and vacationers to seaside

locations around the world.

History

In early times people moved ships with

oars. Many early ships also used the

wind to move across the seas. These

ships had sails—large, raised pieces of

cloth that caught the wind. Ancient

Egyptian warships had at least 40 oars

and a single sail. The powerful longships

of the Vikings also had oars and one sail.

By the 1400s European ships had several

sails. Sailing ships known as galleons

carried large guns along their sides for

making war. In the 1800s long, slim

ships called clippers also had several

sails.

Ships were made mainly of wood until

the middle of the 1800s. At that time

iron ships began to replace wooden

ones. Steam-powered engines also began

to replace sails.

Today most ships are made of steel or

other modern materials. They have

internal-combustion engines that run on

diesel fuel or gas. Some modern ships

run on nuclear power.

#More to explore

Boat • Exploration • Submarine

• Transportation •War

Shoshone

The Shoshone (or Shoshoni) are Native

Americans of the western United States.

They are historically divided into four

groups. The Western Shoshone traditionally

lived in what are now Nevada,

California, and Utah. The Northern

Shoshone lived in what are now Idaho,

Utah, Montana, and Oregon. The Wind

River (or Eastern) Shoshone lived in

what is nowWyoming. The Comanche

were part of theWind River Shoshone

before they split off and moved to what

is now Texas.

TheWestern Shoshone ate mostly roots,

nuts, seeds, fish, and small animals.

SomeWestern Shoshone built huts covered

with brush or bark mats. Others

lived in caves.

A photograph from about the 1890s shows

a Shoshone man named Heebe-tee-tse.

BRITANNICA STUDENT ENCYCLOPEDIA Shoshone 83

The Northern Shoshone fished and collected

wild roots. TheWind River Shoshone

hunted for food. By 1700 the

Northern andWind River Shoshone

had gotten horses. They began to travel

to the Great Plains to hunt bison (buffalo).

There they started to use tepees

covered with bison skins for housing.

The U.S. explorers of the Lewis and

Clark Expedition visited the Shoshone in

1805. Soon after that fur traders,

Mormon settlers, and miners began

arriving in the Shoshone territory. By the

mid-1800s many Shoshone had died

from diseases brought by the newcomers.

The U.S. government pressured the surviving

Shoshone to move to reservations.

At the end of the 20th century there

were about 10,000 Shoshone living in

the United States.

#More to explore

Comanche • Lewis and Clark

Expedition • Native Americans

Shrew

The animals called shrews look like

mice. But unlike mice, shrews are not

rodents. Instead shrews belong to a

group of insect-eating mammals called

insectivores. There are more than 300

species, or types, of shrew.

Shrews live mostly in moist places north

of the equator. They hide in the grass or

dig underground burrows. Except when

mating, shrews live alone.

Shrews are among the world’s smallest

mammals. Some measure only 2.5

inches (6.4 centimeters), including the

tail. Shrews have brownish gray fur and

sharp teeth. A pointed snout overhangs

the lower lip. Shrews have bad eyesight

but a good sense of smell.

Some shrews are active both day and

night.Others are active only at night.

Shrews usually eat more than their body

weight in food each day. Some birds of

prey and snakes eat shrews.However,

most animals will not eat shrews because

shrews can give off a bad smell.

A female shrew gives birth to 2 to 10

young at a time. The furless, blind

babies mature quickly. Most shrews live

only one to three years.

#More to explore

Mammal

Shrimp

#see Crustacean.

A shrew looks out from its burrow.

Shrews are

nervous creatures.

Shock

from a loud

noise or a

rough touch

can kill them.

84 Shrew BRITANNICA STUDENT ENCYCLOPEDIA

Sierra Leone

Sierra Leone is a small country on the

coast ofWest Africa. Its name means

“lion mountains.” It was named for the

hills that surround the country’s main

harbor. The capital is Freetown.

Geography

Sierra Leone shares borders with Guinea

and Liberia. The Atlantic Ocean lies to

the west. Most of the coast is flat and

swampy. The northern coast has some

mountains. Central Sierra Leone is flat

in the north and hilly in the south.

Mountains rise in the east. The climate

is hot and humid.

Plants and Animals

Grasslands cover the north. Forests grow

on the hills and mountains. Palm trees

are common. Sierra Leone’s animals

include monkeys, chimpanzees, tigers,

porcupines, antelope, and crocodiles.

People

The largest groups of people are the

Mende and the Temne. Creoles form a

small group. Their ancestors were slaves

who returned to Sierra Leone after being

freed. Most of the people speak Krio, a

mixture of English and African languages.

About half of the people follow

Islam. Many others follow traditional

African religions. Most of the people live

in the countryside.

Economy

Sierra Leone is a very poor country.

Most people are farmers. Crops include

rice, cassava, peanuts, and sweet potatoes.

Sierra Leone has rich supplies of

diamonds.

History

People have lived in what is now Sierra

Leone for thousands of years. Portuguese

explorers arrived in the 1400s. In the

late 1700s and early 1800s the British

helped freed slaves settle on the coast.

The settlement became known as Freetown.

During the 1800s the British took

control of the area.

Sierra Leone gained independence from

Great Britain in 1961. From 1991 to

2002 rebel groups fought a war against

the government. The civil war forced

hundreds of thousands of people to

leave the country.

..More to explore

Freetown • Slavery

Facts About

SIERRA LEONE

Population

(2008 estimate)

5,969,000

Area

27,699 sq mi

(71,740 sq km)

Capital

Freetown

Form of

government

Republic

Major cities

Freetown, Koidu,

Makeni, Bo,

Kenema

BRITANNICA STUDENT ENCYCLOPEDIA Sierra Leone 85

Sierra Nevada

The mountain range called the Sierra

Nevada has some of the highest peaks in

the United States. It runs along the eastern

edge of California. It also reaches

into western Nevada. Sierra Nevada is a

Spanish name that means “snowy

range.”

The Sierra Nevada is about 400 miles

(640 kilometers) long. Its highest peak is

Mount Whitney, at 14,494 feet (4,418

meters). Mount Whitney is the highest

mountain in the United States outside

of Alaska.

Winds from the west bring warm air

from the Pacific Ocean to the mountains.

The winds also carry a lot of moisture.

Most of the moisture falls as rain or

snow on the western slopes. The eastern

slopes are dry.

Evergreen forests on the western slopes

include cedars, pines, and firs. The bestknown

trees of the mountains are giant

sequoias. They are the largest trees in the

world. The dry eastern slopes have sagebrush,

juniper, and aspen.

Black bears and a few grizzly bears live

in the Sierra Nevada. Smaller mammals

of the mountain forests include American

badgers, bobcats, flying squirrels,

and golden beavers.

Native Americans once lived in the

Sierra Nevada. The first Europeans to

arrive were Spanish explorers and missionaries.

They visited in the 1700s. In

1848 settlers found gold nuggets in

mountain streams. That discovery

started the California gold rush. Fortune

seekers came to the area from all over

the world.

Today tourism is the most important

part of the region’s economy. Yosemite,

Kings Canyon, and Sequoia national

parks attract tourists with their beautiful

scenery. Lake Tahoe is also popular with

visitors.

#More to explore

California • Giant Sequoia • Mountain

Dawn reaches Mount Whitney in the Sierra

Nevada.

86 Sierra Nevada BRITANNICA STUDENT ENCYCLOPEDIA

Sign Language

Through hand movements rather than

speech, people using sign language can

communicate their thoughts and feelings.

Around the world there are more

than 100 sign languages, which are

mainly used by deaf people. Most deaf

people in North America use American

Sign Language (ASL).

What Is Sign Language?

People using sign language make shapes,

called signs, with their hands and arms.

They also move their bodies and make

facial expressions. Signs can stand for

letters, words, or ideas. For example, to

make the sign for cat, ASL users hold

their hands up to their faces and “draw”

whiskers with their fingers.

Sign languages are unique languages.

ASL has different rules of grammar and

different slang than spoken English. ASL

is also different from other sign languages,

including British Sign Language

and Mexican Sign Language.

History

Throughout history both hearing and

deaf people have used some signs to

communicate. For example, babies

quickly learn to point at things they

want. Often people use a system of signs

to communicate with others who speak

different languages.

In the 1700s a priest in France taught

deaf children a system for spelling out

French words with hand gestures. The

system became French Sign Language.

In 1817 Thomas Hopkins Gallaudet

founded the first permanent school for

the deaf in the United States. He had

learned French Sign Language from a

teacher in France. Gallaudet taught his

students the French signs. ASL was

formed by combining Gallaudet’s teachings

with signs that deaf people already

used among themselves.

#More to explore

Deafness • Language

Sikhism

Sikhism is a religion of India that was

started by a man named Nanak. He was

the first of the 10 gurus, or teachers, of

the Sikhs. Most Sikhs live in the state of

Punjab in northwestern India.

Sikhs believe that there is one God. All

people are considered equal and have the

opportunity to become one with God.

Native

Americans

who could not

understand

each other’s

languages

used sign

language to

communicate.

A teacher uses sign language to

communicate with her hearing

impaired students.

BRITANNICA STUDENT ENCYCLOPEDIA Sikhism 87

But first they must overcome selfcenteredness

by honoring God, working

hard, and sharing with others.

Many Sikhs belong to the order called

the Khalsa. Members of the order avoid

alcohol, tobacco, and drugs and devote

themselves to prayer. The men carry

swords. They must not cut their hair or

beards and must cover their hair with a

headdress called a turban.

The main Sikh temple is the Harimandir,

or Golden Temple, in Punjab

state. The Sikh religious book is called

the Adi Granth (First Book). It contains

nearly 6,000 hymns, or songs praising

God, written by Nanak and other gurus.

According to Sikh tradition, in the late

1400s Nanak saw a vision of God, who

ordered him to begin preaching. Nanak

attracted many followers and became the

first of the 10 gurus. The last human

guru was Gobind Singh, who died in

1708. Gobind Singh created the Khalsa

as an armed brotherhood. He felt that

Sikhs were being mistreated by India’s

rulers. He was succeeded as guru by the

Adi Granth, or Guru Granth Sahib

(Guru Granth Personified).

In the 1840s the Sikhs fought two wars

with British forces in the Punjab region.

The British controlled India at the time.

The Sikhs were defeated, and the Punjab

became part of British India.

In 1947 British India gained

independence as two separate countries,

India and Pakistan. The traditional

lands of the Sikhs were divided between

the two. Most Sikhs settled in India,

but the Sikhs and India’s Hindu

majority quarreled. In 1984 Indian

soldiers killed hundreds of Sikhs in an

assault on the Golden Temple. Later

that year the Indian prime minister was

killed by two of her Sikh bodyguards.

The murder led to more violence

against Sikhs. Because of this, many

Sikhs began demanding the

establishment of a separate Sikh state.

In 2004 Manmohan Singh, a Sikh, was

appointed prime minister of India.

#More to explore

India

Silk

Silk is a valuable fiber made mostly by

insects called silkworms. It is used to

make high-quality clothing, sheets, and

other things.

Natural Silk

Silkworms are actually caterpillars, not

worms. A silkworm builds a case called a

cocoon around itself for protection

while it changes into a moth. It makes

A Sikh leader reads from the Adi Granth.

88 Silk BRITANNICA STUDENT ENCYCLOPEDIA

the cocoon with silk that comes out of a

tube in its head. The silkworm wraps a

single long strand of silk around itself

over and over again.

Some spiders also make silk. They weave

silk webs to catch insects to eat. However,

the silk made by spiders is too thin

for making cloth.

The Silk Industry

In the silk industry, silkworms are raised

from the time they are eggs until they

have made a cocoon. In nature, a silkworm

breaks open its cocoon to come

out as a moth. Silkworms used for

industry are killed with hot air or steam

inside the cocoon. This way the cocoon

is not damaged.

To process silk, the cocoons are first put

in hot water. This softens the cocoons so

the silk can be unwound. Several

cocoons are unwound at the same time

to form a single strand. Then several

strands are twisted together to make

thicker, stronger yarn. The yarn can be

dyed and woven into cloth.

History

The silk industry began in China more

than 4,500 years ago. The Chinese

traded silk but would not tell other

countries how it was made. Silk was

such an important product that the

trade route between China and Europe

was called the Silk Road. In the AD 500s

silkworms were stolen from China.

Silk cloth is strong and warm but light in weight. It resists wrinkling and can be dyed with

bright colors.

A silkworm spins its cocoon.

BRITANNICA STUDENT ENCYCLOPEDIA Silk 89

Then Europeans started making silk

themselves.

Today artificial fibers are often used

instead of silk. But people still value silk

items because of their quality. China

remains a major silk producer.

#More to explore

Clothing • Fibers • Spider

Silverstein, Shel

Shel Silverstein’s books, including The

Giving Tree and Where the Sidewalk

Ends, are some of the most famous children’s

books of all time. Silverstein also

wrote books for adults as well as songs

and plays, but he is remembered mostly

for his work for children.

Early Life

Sheldon Alan Silverstein was born in

Chicago, Illinois, on September 25,

1930. When he was about 12 years old,

he became interested in writing and

drawing. In the 1950s he served in the

U.S. military. During that time, Silverstein

worked as a cartoonist for the military

magazine Stars and Stripes.

Career

Silverstein began writing books for children

in the early 1960s. These included

Lafcadio, the Lion Who Shot Back (1963)

and WhoWants a Cheap Rhinoceros

(1964). The Giving Tree (1964) made

him famous with children and parents

across the country. The book tells the

story of a tree that gradually gives a boy

everything it has. Other popular Silverstein

stories include The Missing Piece

(1976) and The Missing Piece Meets the

Big O (1981).

Silverstein also wrote poems. In his serious

poems he showed that he understood

how children think and what they

think about. His humorous verse features

comical scenes and fun-to-say

words and rhymes. His most famous

books of poetry are Where the Sidewalk

Ends (1974), A Light in the Attic (1981),

and Falling Up (1996).

Silverstein died on May 10, 1999, in

KeyWest, Florida. Some poems he had

not yet published appeared in a new

book, Runny Babbit: A Billy Sook, in

2005.

#More to explore

Cartoon • Literature for Children

• Poetry • Storytelling

The Giving Tree is a much-loved book by

Shel Silverstein. The story is about the relationship

between a boy and a tree. Silverstein

also drew the pictures.

Shel Silverstein

was also a

musician. He

wrote

“The Unicorn”

and many

other songs.

90 Silverstein, Shel BRITANNICA STUDENT ENCYCLOPEDIA

Singapore

Singapore is a small, wealthy island

country in Southeast Asia. The capital

city, also called Singapore, is so large and

important that the country is often

called a city-state.

The island of Singapore lies south of the

mainland part of Malaysia. A narrow

body of water separates the countries.

Singapore’s land is mostly low and flat.

Its weather is hot, humid, and often

rainy.

Some rain forests grow in the center of

the island. Shrubs and grasses are more

common. The animals of Singapore

include the long-tailed macaque (a type

of monkey) and the slow loris (a tailless

primate).

Most people in Singapore are Chinese,

Malay, or Indian. The Chinese make up

about three quarters of the population.

Most of the Chinese are Buddhist, Daoist,

or Christian. The Malays and some

Indians follow Islam. Most Indians practice

Hinduism. Singapore has four

national languages: Malay, English, Chinese,

and Tamil (a language of India).

Banking, communications, and other

services are very important to the

economy. Singapore also produces electronics,

chemicals, machinery, petroleum

(oil) products, and other goods.

There is little space for farming. Singapore

buys most of its food from other

countries.

In early times traders traveling between

India and China often passed through

Singapore. The British took control in

the 1800s. By 1959 Singapore had its

own government. In 1963 Singapore

joined Malaysia. Two years later Singapore

separated from Malaysia to

become fully independent.

..More to explore

City-State

A statue of a merlion serves as a symbol of

Singapore. A merlion is an imaginary creature

that is half lion and half fish.

Facts About

SINGAPORE

Population

(2008 estimate)

4,839,000

Area

269 sq mi (697

sq km)

Capital

Singapore

Form of

government

Republic

BRITANNICA STUDENT ENCYCLOPEDIA Singapore 91

Sioux

The Sioux are a group of Native American

peoples who speak similar languages.

There are three main divisions of

the Sioux: the Dakota (or Santee), the

Nakota (or Yankton), and the Lakota (or

Teton).

The Sioux originally lived near Lake

Superior in what is now Minnesota.

They hunted, fished, farmed, and gathered

wild rice and beans.

In the middle of the 1700s wars with

the Ojibwa drove the Sioux westward.

The Dakota settled in southern and

western Minnesota. They kept living as

they had before.

The Nakota and the Lakota moved

onto the Great Plains. The Nakota

settled in what are now North and

South Dakota. The Lakota went farther

west, to the Black Hills region of

western South Dakota and eastern

Wyoming and Montana. The move

changed their lifestyles. The Nakota

and the Lakota started hunting bison

(buffalo) on the plains. While on the

hunt they lived in portable, coneshaped

tents called tepees. They ate

bison meat and used bison skins to

make tepees and clothes.

By the middle of the 1800s white settlers

were moving westward into Sioux

territory. The Sioux fought for many

years to stop invasions of their land.

Sitting Bull and Crazy Horse were

famous Sioux chiefs who led the fight.

In 1890 U.S. troops killed more than

200 Sioux at a place called Wounded

Knee in South Dakota. The massacre

ended the Sioux fight against the whites.

By the end of the 1800s most Sioux had

moved to reservations.

At the end of the 20th century there

were about 108,000 Sioux in the United

States. Many lived on reservations in

Montana, Nebraska, North Dakota, and

South Dakota. About 10,000 more

Sioux lived in Canada.

#More to explore

Black Hills • Crazy Horse • Native

Americans • Sitting Bull •Wounded

Knee

Sitting Bull

Sitting Bull was a Native American who

tried to keep U.S. settlers from taking

over Indian lands. He is known for his

role in the battle of the Little Bighorn.

A photograph from the 1890s shows a

Sioux holding a bow and arrows.

92 Sioux BRITANNICA STUDENT ENCYCLOPEDIA

In that battle he defeated a group of

soldiers led by Lieutenant Colonel

George Armstrong Custer.

Sitting Bull was a member of the

Lakota, or Teton Sioux. He was born in

about 1831 near the Grand River in

what is now South Dakota. His Sioux

name was Tatanka Iyotake. He was

named chief of the entire Sioux nation

in about 1867.

Sitting Bull spent many years battling

U.S. soldiers. Tensions increased when

gold was found on Sioux lands. The

U.S. government soon ordered the

Sioux to move to reservations. Sitting

Bull, however, prepared to fight the

move. On June 25, 1876, U.S. soldiers

led by Custer attacked the Indians. The

battle took place in the valley of the

Little Bighorn River. When the fighting

ended, Custer and all of his soldiers

were dead.

Sitting Bull won many more battles. But

he and his people were eventually forced

to surrender.

Sitting Bull toured for a time with Buffalo

Bill’sWildWest Show. He later

settled on a reservation but remained

outspoken. Soldiers arrested him

because they were afraid he would stir

up trouble. He was killed on December

15, 1890, as his warriors were trying to

rescue him.

#More to explore

Sioux

Skateboarding

A skateboard is a small board with

wheels on the bottom. A skateboarder

stands on the board as it rolls. The skateboarder

stays balanced by shifting the

A professional skateboarder

wears a helmet and padding

while performing a difficult stunt

on a closed-off ramp. Skateboarders

should stay safe at all

times.

Sitting Bull was a leader of the

Sioux people. He was known for

his bravery and wisdom.

BRITANNICA STUDENT ENCYCLOPEDIA Skateboarding 93

feet and body. Many young people enjoy

skateboarding as a hobby. It is also an

organized sport. The best skateboarders

can invent and perform difficult tricks.

Most skateboards are about 32 inches

(81 centimeters) long and 9 inches (23

centimeters) wide. The back end of a

modern skateboard is bent upward. This

is called the kicktail. The wheels are

made of a special kind of tough plastic.

Skateboarding Styles and

Events

The two main styles of sport skateboarding

are vertical (or vert, for short) and

street style. Vertical skaters jump off

ramps or perform in U-shaped riding

surfaces called half-pipes. They do tricks

in midair. Street-style skaters perform in

city environments. They ride their skateboards

over objects such as steps, railings,

and ledges.

These styles of skateboarding have been

organized into competitions. Events are

held in Australia, Brazil, Canada, and

the United States, and throughout

Europe and Asia. Skateboarding is also a

part of the televised sports festival called

the X Games.

History

The first skateboarders made their own

boards in the early 1900s. The simplest

homemade skateboards had roller-skate

wheels attached to a board.

Skateboarding became popular in the

early 1960s. It developed among surfers

in California, in the United States. Surfers

use special boards to ride on waves in

the ocean. When there were no good

waves for surfing, some surfers changed

their boards. They added wheels so they

could ride on the sidewalks near the

ocean. Skateboarding was even called

sidewalk surfing.

The first skate parks were built in the

1970s. They had slopes and banked

surfaces for sudden turns and stunts. But

some skateboarders chose to skate in

empty swimming pools. This was the

beginning of vertical skateboarding.

Soon skateboarders started riding in

half-pipes. Street-style skating started in

the 1980s.

Skating

Skating is a form of sport that has three

main types: ice skating, roller skating,

and skateboarding. Ice skating is the

American

skateboarder

Tony Hawk

helped make

the sport

popular in the

1980s and

1990s.

Many people enjoy skating as a casual

form of entertainment. For others it is a serious

sport.

94 Skating BRITANNICA STUDENT ENCYCLOPEDIA

oldest form of skating. Thousands of

years ago people used animal bones as

skates to cross frozen bodies of water.

Modern ice skates are shoes or boots

with metal blades attached. Ice skating

has three main divisions: figure skating,

speed skating, and ice dancing. The

team sport of ice hockey also involves

skating.

Roller skates have wheels instead of

blades. Indoor types of roller skating

include roller dancing, figure skating,

and speed skating on hardwood, plasticcoated

tracks. Roller hockey is usually

played outdoors. In the 1980s roller

skaters started to use in-line skates, or

Rollerblades. They are faster than traditional

roller skates.

Skateboarding is a popular sport that

began in the U.S. state of California in

the early 1960s. Young people started

skateboarding on pavement near beaches

when the ocean was too calm for surfing.

A skateboard is like a small surfboard

with wheels. Skateboard parks

provide a variety of slopes and surfaces

for riding.

#More to explore

Hockey, Ice • Ice Skating • Roller

Skating • Skateboarding

Skeletal System

The collection of bones in an animal’s

body is called a skeletal system, or skel-

Fish, birds, reptiles, and mammals are four types of animals that have skeletons inside

their bodies. The skeletons of a perch, a chicken, a crocodile, and a cow are shown.

BRITANNICA STUDENT ENCYCLOPEDIA Skeletal System 95

eton. Mammals, birds, reptiles, amphibians,

and fish have skeletal systems.

Insects and shellfish do not have skeletons

inside their bodies. Instead they

have hard, outside coverings called

exoskeletons. The skeletons of corals and

sponges are made of stony minerals, not

bone. Some animals, such as jellyfish,

have no skeleton at all.

The human skeletal system has more

than 200 bones. The hard, stiff bones of

the skeleton support the whole body.

The skeleton also protects the soft

organs inside the body. In addition, the

skeleton works with the muscles to allow

the body to move.

Support

The most basic job of the skeletal system

is support. For example, the spine, or

vertebral column, supports the entire

upper part of the body. The human

spine lets people stand and walk in an

upright position, or posture. Humans

enjoy great advantages over other animals

because of this posture. Because

humans use only their legs for walking,

their arms are free for useful activities,

such as using tools.

Protection

The second major job of the skeletal

system is protection. The skeleton’s rigid

structure protects the body’s soft organs.

For example, the rib cage formed by the

spine and the ribs protects the heart, the

lungs, and other organs in the upper

body.

The skeletal system also protects the

central nervous system, made up of the

The human skeleton is mostly bone but has

some cartilage. The skeleton supports and

protects the body.

96 Skeletal System BRITANNICA STUDENT ENCYCLOPEDIA

brain and the spinal cord. Inside the

head, the skull surrounds and protects

the brain. The vertebrae, or bones of the

spine, surround and protect the nerves

of the spinal cord.

Movement

The third major job of the skeletal system

is movement. The skeleton works

with the muscles to allow the body to

move in many different ways. Many

muscles are attached to at least two

bones in the skeleton. When the brain

tells a muscle to move, the muscle pulls

on or pushes its attached bones.

How the Skeletal System Is

Connected

Tough, leathery tissues called ligaments

hold together the bones of the skeleton.

Muscles also hold together some of the

bones. In most cases, however, a cord

called a tendon connects muscles to

bones.

At the points where bones connect, the

bones have a protective covering called

cartilage. If two hard bones constantly

rubbed together without this covering,

they would wear down and become

damaged. Cartilage is tough enough to

protect the bones but elastic enough

not to become damaged itself. It is

found at the ends of many bones and

in joints, such as the knees and the

hips. Cartilage also connects parts of

the rib cage. The cartilage allows the

ribs to move in and out during

breathing.

Cartilage can be damaged, however, and

it is not easily repaired. As people get

older, the cartilage in some joints can

wear down. This allows the bones of

the joints to rub together painfully. In

such cases doctors can replace the joints

with artificial joints made of plastic or

metal.

#More to explore

Bone • Exoskeleton • Muscle • Nervous

System

Skiing

Skiing is a winter sport that involves the

use of skis. Skis are long, mostly flat

strips of metal, wood, or plastic. Skiers

attach them to their shoes or boots and

use them to glide over snow, often down

a mountain slope. Many people ski for

fun. Skiing can be fast and exciting, but

it can also be dangerous.

Skiing events are a major feature of the

Winter Olympic Games. Four types of

skiing events are held at the Olympics:

An infant’s

skeleton is

made of

cartilage that

is gradually

replaced by

bone as the

infant grows

into an adult.

A view of a knee joint shows the different

kinds of connective tissue that hold together

the human skeleton.

BRITANNICA STUDENT ENCYCLOPEDIA Skiing 97

events include downhill and slalom

racing. Downhill racing is the fastest and

most dangerous of all skiing events. The

skier goes down a long, steep course that

may have ruts and large bumps. Along

the course are gates formed by single

poles or pairs of poles. The skier must ski

between the gates and stay on the course.

The winner is the skier who completes

the course in the shortest time.

Slalom racing is similar to downhill racing.

However, a slalom course is shorter

and more winding than a downhill

course. The slalom course requires the

skier to make high-speed turns. The

giant slalom and the supergiant slalom,

or super-G, take place on longer versions

of a slalom course.

Freestyle Skiing

Freestyle skiing combines skiing and

acrobatics. There are three freestyle

events: acro, aerials, and moguls. An

acro skier performs jumps, flips, and

spins while skiing on a gently sloping

hill. An aerial skier does similar tricks

in the air after jumping off a ramp. A

mogul skier races over and around large

bumps of snow, called moguls. The

mogul skier also makes two jumps and

does tricks in the air. In freestyle events

judges score the skiers on different

skills.

Snowboarding

Snowboarding developed in the United

States from the sports of surfing and

skateboarding. It is like surfing on snow.

A snowboard looks much like a skateboard

without wheels.

Snowboarding has slalom, giant slalom,

and supergiant slalom (or super-G)

competitions. These events are similar to

the Alpine slalom events. The snowboarder

who completes the course in the

shortest time is the winner.

There are also freestyle snowboarding

events. They take place on a half-pipe,

which is a ramp built from snow. The

ramp looks like the lower half of a huge

flat-bottomed tube with one open end.

A freestyle skier on a moguls course goes

over many bumps. On an aerials course,

the skier jumps from a ramp to perform flips

and twists in the air.

BRITANNICA STUDENT ENCYCLOPEDIA Skiing 99

Snowboarders ski from side to side of

the ramp, picking up speed. They fly up

from the top of the ramp and do tricks

in the air. Judges rate the performances.

History

Skis found in Sweden and Finland are

thought to be between 4,000 and 5,000

years old. A rock carving of two men on

skis, found in Norway, dates from 2000

BC. People in China have skied since at

least the AD 600s. Skiing was used in

warfare in Norway as early as 1200.

Troops in Sweden, Finland, Russia, and

Poland also used skis.

Cross-country is the oldest form of sport

skiing. Cross-country competitions

began in Norway in the 1840s. By the

1860s skiing had reached the U.S. state

of California. Ski-jumping competitions

began in the 1870s. Nordic skiing events

were a part of the firstWinter Olympics,

held in 1924.

Alpine skiing developed during the late

1800s and early 1900s. Alpine events

became a part of the Olympics in 1936.

Freestyle skiing and snowboarding are

newer events. Mogul and aerial skiing

were added to the Olympics in the

1990s. Snowboarding events were first

held at the 1998 Olympics.

#More to explore

Olympic Games

A snowboarder on a half-pipe course goes back and forth from one side of the half-pipe

to the other.

100 Skiing BRITANNICA STUDENT ENCYCLOPEDIA

Skin

Skin is the outer covering of humans

and all other animals with a backbone.

It protects the body from germs, injuries,

and extremes of hot or cold.

The skin of some animals has special

features that provide more protection.

Birds, for example, have feathers

attached to their skin. Fish and reptiles

have plates called scales over their skin.

Most mammals have a thick coat of hair

called fur. Humans have hair on their

skin, too, but not enough to act as protection.

Human skin has three layers. The epidermis

is the thin outer layer. Dead cells

of the epidermis constantly flake off as

new ones form. Cells in the epidermis

produce a substance called melanin.

Melanin creates different skin colors.

The epidermis has cells that make nails,

too.

The middle skin layer is called the dermis.

It is thicker than the epidermis,

which it supports and strengthens. The

dermis has fibers that make the skin

tough and stretchable. Pits in the dermis,

called follicles, make hair. The dermis

also contains blood vessels and

nerves. Nerves are fibers that send information

picked up by the senses to the

brain.

The third, deepest layer of the skin is

made up mostly of fat. This fat supplies

nutrients to the other two layers. It also

cushions the body and protects it from

the cold.

The body releases some substances

through the skin. Sweat glands send a

watery liquid called sweat through pores,

or tiny openings, on the skin’s surface.

Sweat cools the body. Other glands in

the skin produce an oil that can give the

skin a slightly greasy surface. This oil

helps keep the skin flexible.

Skin can be irritated or damaged in a

number of ways. Viruses can cause skin

blisters known as shingles. Extra oil production

can cause a condition called

acne. Skin burns can be caused by fire,

chemicals, electric shock, or the sun.

#More to explore

Acne • Burn and Scald • Feather • Hair

• Nail and Claw

Human skin has three layers: the epidermis,

the dermis, and a layer made mostly of fat.

Hair follicles, oil glands, sweat glands,

nerves, and blood vessels lie beneath the

surface of the skin.

BRITANNICA STUDENT ENCYCLOPEDIA Skin 101

Skopje

Population

(2004 estimate)

506,930

Skopje is the capital of Macedonia, a

country in southeastern Europe. The

city lies on the Vardar River. It is Macedonia’s

largest city by far.

Skopje is Macedonia’s center of business

and industry. Factories in the city process

foods, cement, metals, and other

products. Trade, banking, tourism, and

other services are also important.

People called the Illyrians founded Skopje

in ancient times. By the 300s the city

was the capital of a province of the

Roman Empire. In 518 an earthquake

destroyed the city, but it was rebuilt.

The Serbs conquered Skopje in 1189.

The Turkish Ottoman Empire controlled

the Macedonia area from 1392

until 1912.

In the early 1900s Skopje and the rest of

Macedonia became part of the country

of Yugoslavia. In 1963 an earthquake

destroyed most of the city. Skopje was

rebuilt with many modern buildings. In

1991 Macedonia became an independent

country. Skopje was its capital.

..More to explore

Macedonia

Skull

In animals with a backbone, including

human beings, the skull forms the hard

part of the head. It surrounds and protects

the brain. The skull is a part of the

body’s skeletal system.

The human skull must be large enough to

protect a large brain.

102 Skopje BRITANNICA STUDENT ENCYCLOPEDIA

The skull is made up of several bones

that are joined together like a jigsaw

puzzle. Many of the other bones of the

body meet at movable joints. The bones

of the skull, however, meet at joints that

do not move. (The lower jawbone,

which does move, is not really a part of

the skull.)

The cranium is the part of the skull that

covers the brain. The human cranium is

noticeably larger than the part of the

skull that makes up the face. In most

other animals the opposite is true—the

face is larger than the cranium.

Openings in the skull let air move

through the nose. Other openings form

eye sockets that support and protect the

eyes. The spinal cord, which is the

body’s main nerve, enters the skull

through an opening at its bottom.

Nerves from the eyes, the nose, the ears,

and the tongue pass through smaller

openings on their way to the brain.

The skull rests on the atlas, which is the

topmost vertebra, or bone, of the spine.

This allows the skull to nod up and

down. The atlas can turn on the vertebra

directly beneath it. This allows the skull

to turn from side to side.

..More to explore

Bone • Brain • Skeletal System

Skunk

Skunks are black and white mammals

known for the foul-smelling spray they

release when threatened. When a skunk

feels trapped or in danger, it showers this

spray on the creature that threatens it.

Skunks are found throughout the

Americas. They live in many different

places, including woods, grasslands,

deserts, and mountains. Many skunks

are comfortable in towns and cities.

Skunks are usually the size of a house

cat, though some are much smaller.

They have a bushy tail. Skunks have

different patterns of black and white in

their fur. One common pattern is black

with a white patch on the head and one

or two white stripes on the back. Other

skunks have a mostly white back and tail

or white spots in black fur.

Most skunks are active at night. They

eat insects, eggs, small rodents, birds,

and fruits. When a skunk feels threatened,

it lifts its tail and stamps its feet. If

this does not chase away the enemy, the

skunk sprays its smelly liquid. It can

shoot this liquid as far as 12 feet (3.7

meters). A skunk usually aims the spray

The striped skunk is a common skunk of

North America.

BRITANNICA STUDENT ENCYCLOPEDIA Skunk 103

at the eyes of its enemy. This blinds the

enemy temporarily, letting the skunk

escape.

..More to explore

Mammal •Weasel

Skyscraper

A skyscraper is a very tall building with

many stories, or floors. Early skyscrapers

had 10 to 20 stories. Today some skyscrapers

have 100 stories or more.

Two developments in the middle of the

1800s helped to make the modern skyscraper

possible. The first was a process

for making large amounts of steel. The

second was the invention of the passenger

elevator.

Before this time brick or stone walls

alone carried the weight of upper stories.

The tremendous weight of each story

made it impossible to build very high.

Some architects (people who design

buildings) used an iron frame to support

taller buildings. But even these buildings

were not much higher than four or five

stories.

In the 1860s steel became widely available.

This metal is both stronger and

lighter than iron. Architects could now

use a steel skeleton to support very tall

buildings. Chicago’s Home Insurance

Company Building was the first skyscraper

to use this type of steel construction.

Built in 1884–85, it was 10 stories

high.

Skyscrapers would not have been useful

without elevators. People could not

A cluster of skyscrapers stands near the Singapore

River in Singapore.

Four of the world’s tallest buildings are

shown side by side. The Willis (formerly

Sears) Tower and the Empire State Building

have antennas that do not count as part of

the height. The Taipei 101 is located in

Taipei, Taiwan. The Petronas Towers 1 & 2

are found in Kuala Lumpur, Malaysia. The

Willis Tower is in Chicago, Illinois, and the

Empire State Building is in New York City.

104 Skyscraper BRITANNICA STUDENT ENCYCLOPEDIA

regularly walk up and down more than

five or six flights of stairs. In 1853 a

U.S. inventor named Elisha Graves Otis

introduced an elevator safe enough to

carry passengers.

During the 1920s and 1930s skyscrapers

rose to greater heights than ever before.

For many years the Empire State Building

(completed in 1931) in New York

City was the world’s tallest building. It

is 1,250 feet (381 meters) tall and has

102 stories. Today several skyscrapers are

even taller.

#More to explore

Architecture • Steel

Slavery

The practice of people owning other

people is called slavery. The owned

people are called slaves. They have to

work for the owners, doing whatever the

owners ask them to do. In the past,

many societies had slavery. Now almost

all societies consider slavery to be wrong.

They consider personal freedom to be a

basic human right.

The Lives of Slaves

People became slaves in many ways.

Some became slaves after being captured

in wars or raids. Others became slaves

because they had committed crimes or

could not pay their debts. Some people

were sold into slavery by their relatives.

Others were the children of slaves.

Different societies had different rules for

slavery. Many slaves of the Muslims, for

example, had to be freed after six years.

Slaves in the United States, however,

stayed slaves forever. They could not

own any property. Their marriages were

not legal, and their families could be

broken up at any time. There were laws

against killing or mistreating slaves, but

governments did not always enforce

these laws.

Slaves got no pay, had no choice of jobs,

and were not allowed to quit. Other

kinds of workers had limits on their

freedom but were still freer than slaves.

Serfs were farmworkers who were legally

tied to the land on which they worked.

They received no pay and were not free

to move away, but they could not be

bought or sold like slaves. Indentured

servants were people who agreed to work

for a master for a certain period of time.

People became indentured servants to

pay their debts.

Slaves did a variety of jobs. Most slaves

worked on farms. Many did cooking,

cleaning, child care, and other house-

A monument honors enslaved Africans who

died in 1830. Their ship sank off the coast

of Martinique, an island in the West Indies.

BRITANNICA STUDENT ENCYCLOPEDIA Slavery 105

hold services for the families that owned

them. Others worked to make money

for their owners. Some slaves worked in

mines.

Early Slavery

Slavery existed throughout the ancient

world. It was practiced in China before

1200 BC. There were laws about slaves in

the Middle East from about 1750 BC

and in India from about 100 BC.

In Athens, a city of ancient Greece,

about one third of the people were

slaves. In ancient Rome, slaves worked

on farms, rowed warships, did construction

work, or copied out books. In the

later days of the Roman Empire, slaves

on farms eventually became serfs.

In the early Middle Ages, after about AD

500, Europeans took many Slavs (a

people of eastern Europe) as slaves. The

word slave comes from “Slav.” Serfs

slowly replaced slaves in all of Europe.

There were serfs in parts of Europe into

the 1800s.

Enslaved Africans

Slavery also existed in Africa in ancient

times. But the African slave trade across

the Atlantic Ocean began in the early

1500s. European ship captains bought

slaves from African traders. The ships

then usually carried the slaves to Brazil

or a Caribbean island. Conditions on

slave ships were terrible, and many

people died.

Those who survived were sold to owners

in many parts of the Americas. Owners

put Africans to work in mines or on

large farms that grew tobacco or sugar.

The farms needed African slaves to

replace Native American workers. European

diseases had nearly wiped out these

Native Americans.

The first African slaves in North

America arrived in the English colony of

Virginia in 1619. All the British colonies

permitted slavery, but the large farms

that used the most slaves were in the

South. At first, tobacco was the most

important crop. Then, in 1793, Eli

Whitney invented a machine called the

cotton gin. His invention made cotton

easier to process. This led to a huge

demand for African slaves to work on

large cotton farms called plantations.

Ending Slavery

During the 1700s some people in Great

Britain came to think that slavery was

Enslaved Africans had no room to move on a ship that took them across the Atlantic Ocean.

106 Slavery BRITANNICA STUDENT ENCYCLOPEDIA

wrong. They began the abolitionist

movement, an effort to end slavery. Both

Britain and the United States banned the

slave trade in the early 1800s. Starting

with Vermont in 1777, the northern

parts of the United States banned slavery

entirely.

However, the large Southern plantations

continued to rely on slave labor. Some

slaves escaped through a secret organization

called the Underground Railroad,

but the system of slavery survived. In

some states more than half the people

were slaves.

The big issue that divided the United

States was whether slavery would be

allowed in new territories and states.

The Missouri Compromise of 1820

settled the problem for a time. It allowed

slavery in some new territories but not

others. However, the Kansas-Nebraska

Act of 1854 allowed the people in new

territories to choose to have slavery. In

the Dred Scott case of 1857, the U.S.

Supreme Court ruled that the government

did not have the power to ban

slavery in the territories. In 1861 the

American CivilWar began, partly over

the issue of slavery. At the end of the

war, the 13th Amendment to the Constitution

finally put an end to slavery in

the United States.

In Central and South America, as soon

as colonies gained independence, they

often banned slavery. The last country in

theWestern Hemisphere to end slavery

was Brazil, in 1888.

By the late 1800s the British abolished

slavery in India and in the parts of

Africa that they controlled. Slavery

ended in China in 1910.

Some parts of Africa and the Islamic

world practiced slavery well into the

1900s. Although all countries had officially

outlawed slavery by the end of the

1900s, the practice continued in some

parts of Africa and Asia.

#More to explore

Abolitionist Movement • American Civil

War • Dred Scott Decision • Human

Rights • Kansas-Nebraska Act

• Missouri Compromise • Underground

Railroad

Sleep

Many animals, including humans, sleep.

When people sleep, their eyes are closed,

their muscles are relaxed, and they are

usually lying down. Getting enough

sleep is an important part of being

healthy.

Small houses on the grounds of a Southern

plantation were once the homes of slaves.

BRITANNICA STUDENT ENCYCLOPEDIA Sleep 107

Scientists are not sure exactly why people

and other animals sleep. Some scientists

think that sleep is a way for animals to

save energy, because the body uses less

energy when asleep than when awake.

Other scientists think that sleep allows

the body and mind to rest and recover

from the day’s activities. People who do

not get enough sleep may have difficulty

remembering and concentrating.

People need different amounts of sleep

at different times in their lives. A new

baby may sleep for as many as 16 hours

a day by taking frequent naps. A 2-yearold

child usually naps during the day

and sleeps for a longer period through

the night. As children grow into adults,

they usually stop taking regular naps and

sleep for a single, long period each

night. The average amount of sleep for

an adult ranges from six to nine hours

each night. Elderly people may nap

often during the day and sleep only a

few hours at night.

Sloth

Sloths are slow-moving mammals that

spend most of their lives in trees. They

cling to the trunks or hang upside down

from the branches. Sloths live in the

tropical forests of Central and South

America. They are related to armadillos

and anteaters.

Sloths can grow up to 27 inches (69

centimeters) long. They have thick skin

and either a short, stumpy tail or no tail

at all. The fur is usually grayish brown

or tan. Sloths often have a greenish tint

because of algae on their fur. The algae

protects sloths from other animals by

helping them to blend in with tree

leaves.

Sloths have either two or three toes on

their feet. The toes have long, curved

claws, which the sloth uses to grasp

branches. Two-toed sloths spend much

of the time hanging onto trees with all

four legs. Three-toed sloths often sit on

the branches rather than hang from

them.

Sloths are quiet animals that live alone.

They sleep most of the day. Sloths sleep

hanging upside down, with the head

tucked up between the front legs. At

night they move very slowly through the

trees eating leaves and fruit. Sloths rarely

come down from the trees because they

cannot walk.

#More to explore

Anteater • Armadillo • Mammal

Most dreams

occur during a

part of sleep

when there

are rapid eye

movements

(REMs). People

usually have

three to five

periods of

REM sleep per

night.

A three-toed sloth clings to a tree

trunk.

108 Sloth BRITANNICA STUDENT ENCYCLOPEDIA

Slovakia

Slovakia is a small country in central

Europe. From 1918 to 1992 Slovakia

was part of the country of Czechoslovakia.

Slovakia’s capital is Bratislava.

Slovakia shares borders with the Czech

Republic, Poland, Ukraine, Hungary,

and Austria. The Carpathian Mountains

run across northern Slovakia. Lower

mountains rise in the center. Slovakia

has cool summers and cold winters.

Forests cover nearly half of Slovakia.

Alpine grass and shrubs grow in the

highest areas. Bears, wolves, lynx, wildcats,

otters, and mink live in the mountains.

Slovakia’s many birds include wild

geese and herons.

Slovaks make up most of the population.

The rest of the people are mainly

Hungarians. Slovak is the main language.

Roman Catholicism is the most

common religion.

Banking, tourism, and other services are

large parts of Slovakia’s economy.

Manufacturing and mining are also

important. Factories produce metals,

machinery, flour, fuels, paper, and other

goods. Mines provide iron and coal. The

main crops grown in Slovakia are wheat,

sugar beets, and corn.

Tribes of people called Slavs settled Slovakia’s

land in the 500s or 600s. Hungary

later conquered the region. In 1526

the Hapsburg Empire of Austria took

over Hungary and Slovakia. After 1867

Slovakia was a part of the Austro-

Hungarian Empire. In 1918 Slovakia

joined a new country called Czechoslovakia.

In 1989 the people of Slovakia voted to

separate from Czechoslovakia. Slovakia

became an independent country on

January 1, 1993. In 2004 Slovakia

joined the European Union.

..More to explore

Bratislava • Czechoslovakia

The oldest parts of Orava Castle in Slovakia

are more than 700 years old.

Facts About

SLOVAKIA

Population

(2008 estimate)

5,401,000

Area

18,933 sq mi

(49,035 sq km)

Capital

Bratislava

Form of

government

Republic

Major cities

Bratislava,

Kosice, Presov,

Nitra, Zilina,

Banska Bystrica

BRITANNICA STUDENT ENCYCLOPEDIA Slovakia 109

Slovenia

Slovenia is a country in the Balkans, a

region of southeastern Europe. The capital

is Ljubljana.

Slovenia shares borders with Italy, Austria,

Hungary, and Croatia. In the southwest

Slovenia has a short coastline on

the Adriatic Sea.

Parts of the Alps mountains stretch

across northern Slovenia. The Sava and

Drava rivers flow down through the east.

In the southwest is the Karst, a rocky

region with many caves. Most of Slovenia

has cool or warm summers and

cold winters.

Slovenia’s many forests include juniper,

birch, and beech trees in the hilly areas.

Shrubs grow in the lower areas. Brown

bears, wolves, lynx, wild boars, and deer

live in Slovenia.

Most of Slovenia’s people are Slovenes.

Their language is also called Slovene.

Most of the Slovenes are Roman Catholics.

Small groups of Serbs, Croats, Bosniacs

(Muslims), and others also live in

Slovenia.

Manufacturing is important to the

economy. Slovenia produces iron and

steel, electronics, cloth, chemicals, wood

products, and motor vehicles. Banking

and other services are also important.

Slavic people, the ancestors of the Slovenes,

settled in the region in the 500s.

Over the centuries different powers

ruled the Slovenes. In 1918 Slovenia

joined the new Kingdom of Serbs,

Croats, and Slovenes. The country was

renamed Yugoslavia in 1929. Slovenia

broke away from Yugoslavia in 1991. In

2004 Slovenia joined the European

Union.

..More to explore

Balkan Peninsula • Communism

• Ljubljana • Yugoslavia

A town sits in a valley near the Alps mountains

in northern Slovenia.

Facts About

SLOVENIA

Population

(2008 estimate)

2,029,000

Area

7,827 sq mi

(20,273 sq km)

Capital

Ljubljana

Form of

government

Republic

Major cities

Ljubljana, Maribor,

Celje, Kranj,

Velenje

110 Slovenia BRITANNICA STUDENT ENCYCLOPEDIA

Smallpox

Smallpox is a dangerous disease caused

by a tiny germ called a virus. Smallpox

once killed or scarred many people.

However, in the late 20th century scientists

fought the disease successfully.

There have been no naturally occurring

cases of smallpox since the 1970s.

People who have the smallpox virus can

spread it to other people through their

breath or saliva. The virus also can live

on bedding or clothing. Once a person

is infected by the smallpox virus, there is

no cure for the disease.

People with smallpox get a high fever.

They also get body aches and become

very tired. A rash appears on the skin.

The rash changes into blisters. People

can die from smallpox. People who survive

may suffer permanent damage such

as scars or blindness.

Smallpox existed for thousands of years

in Europe, Asia, and Africa. Explorers

brought the disease to the Americas after

1492. Many Native Americans died

from it. Large outbreaks of smallpox

happened around the world.

In 1796 an English doctor named

Edward Jenner discovered a smallpox

vaccine. A vaccine is a substance that

prevents people from getting a disease.

In 1967 a group called theWorld

Health Organization began giving the

smallpox vaccine to people around the

world. The project was a success. By

1979 there were no cases of smallpox

anywhere in the world.

#More to explore

Disease, Human • Vaccine • Virus

Snail and Slug

Snails and slugs are similar animals. The

main difference between them is that a

snail has a shell and a slug does not.

Snails and slugs belong to the group of

soft-bodied animals called mollusks,

which also includes oysters, clams, and

squid.

Snails and slugs are found throughout

the world. Some live on land or in trees.

Others live in water. Some snails and

slugs spend the winter underground.

Most snails and slugs are small and drab.

A snail has a coiled body and shell. The

shell protects the snail from heat and

enemies. Snails can make their shells

A doctor gives a girl a shot of a vaccine in

the 1960s to protect her against smallpox.

Doctors vaccinated so many people that

today the chances of catching the disease

are very small.

BRITANNICA STUDENT ENCYCLOPEDIA Snail and Slug 111

bigger as they grow. Slugs have straight

bodies. Both snails and slugs have two

long tentacles sticking out from the

head. Each tentacle has an eye at the tip.

Snails and slugs move by gliding on a

foot. They make a slimy fluid that helps

the foot glide.

Snails and slugs eat plants. Slugs also eat

dead animal material and sometimes

worms and snails. Snails and slugs are

eaten by snakes, toads, turtles, beetles,

and birds.

Gardeners consider snails and slugs to be

pests. But people eat some types of land

snails, especially in France.

#More to explore

Mollusk • Shell

Snake

A snake is a reptile with a long, slender

body but no arms or legs. Snakes are

closely related to lizards. There are about

2,900 species, or kinds, of snake. The

best-known snakes include cobras,

vipers, boas, and pythons.

Where Snakes Live

Snakes are found throughout the world

except near the North and South poles.

The tropics have the greatest variety.

Most snakes live on the ground, but

others prefer trees. Some snakes spend

their whole lives in underground tunnels.

Sea snakes live in water.

Physical Features

Snakes are vertebrates, or animals with a

backbone. The backbone is long and

flexible. Snakes grow throughout their

lives. The longest known snake is the

reticulated python, which can grow to

32 feet (10 meters). The giant anaconda

is usually not as long but is much

heavier. The smallest snakes are the

blind snakes. Some of them are barely 4

inches (10 centimeters) long.

Snakes are covered with rows of scales.

Scales are hardened folds in the outer

layer of skin. A scale can be shiny and

smooth, or it can have a ridge running

down the middle. A snake molts, or

sheds its skin, many times during its life.

Snakes have no ears or eyelids. Clear

scales cover the eyes. A snake’s mouth

opens wide because the lower and upper

jaw can separate. Most snakes have long,

needle-sharp teeth that curve backward.

Some snakes, including cobras and

rattlesnakes, have a long front or back

pair of teeth called fangs. A snake’s

tongue is forked.

A snail glides along the surface of a leaf.

112 Snake BRITANNICA STUDENT ENCYCLOPEDIA

Snakes come in many different sizes and colors.

BRITANNICA STUDENT ENCYCLOPEDIA Snake 113

Behavior

Snakes eat mice, rats, birds, frogs, fish,

insects, lizards, eggs, and sometimes

other snakes. Most snakes swallow their

prey whole, usually head first. The prey

may be dead or alive when eaten. Boas,

pythons, king snakes, and rat snakes are

called constrictors. They coil around

their prey and constrict, or squeeze, the

animal to death before eating it. Vipers

and cobras kill their prey by shooting

venom, or poison, into it through their

fangs.

Without ears, snakes cannot hear most

sounds. But they can sense when prey is

near through vibrations in the ground.

Snakes can see very well, too. Snakes

flick out their tongue to “taste” the air,

which gives them information about

their surroundings. Snakes do not have

vocal cords. This means that they are

voiceless. However, they can make a

hissing sound by sending air through an

opening in the mouth.

A snake’s color can help protect it from

enemies. Some snakes blend in with

their surroundings. For example, many

tree snakes are bright green and resemble

vines. The bright colors of some snakes

warn attackers that they are poisonous.

Snakes are cold-blooded animals. This

means that their body temperature

changes along with the temperature of

their surroundings. To survive cold seasons,

some snakes go into hiding places

and become inactive for months at a

time. This is like hibernation in mammals.

Movement

Most snakes move by pushing the scales

on the underside of their body against

the ground. The body moves in a series

of S-shaped loops. Some large snakes,

such as the boas, move in a straight line.

They inch their body forward like a caterpillar

does. Other snakes move by

folding and unfolding like an accordion.

Many desert snakes use a movement

called sidewinding. They throw their

body upward and sideways across the

sand.

Life Cycle

Most snakes live alone for most of the

year. Some kinds gather for mating or

hibernation. Most snakes lay eggs, but

others give birth to live young. The

number of young varies from about 3 to

more than 50. At birth, baby snakes

look like adult snakes. Snakes kept by

people can live more than 30 years.

Snakes in the wild do not live as long.

A black-and-yellow mangrove snake sticks

out its forked tongue. A snake uses its

tongue to gather information about its surroundings.

114 Snake BRITANNICA STUDENT ENCYCLOPEDIA

Snakes and Humans

Some people think snakes are scary and

dangerous. However, a snake bites a

human only when it is frightened or

threatened. Plus, snakes eat rats and

mice, which most people consider to be

pests. People hunt snakes as a source of

clothing and food. Some snakes are captured

and sold as pets.

#More to explore

Anaconda • Boa Constrictor • Cobra

• Lizard • Python • Rattlesnake • Reptile

• Sea Snake • Viper

Snow

Tiny crystals of ice that fall to Earth are

called snow. A crystal is a solid substance

that has flat surfaces and sharp corners.

Snowfall is made up of both single ice

crystals and clumps of ice crystals. The

clumps are called snowflakes.

How Snow Forms

Snow is formed high in the clouds from

water vapor, which is water in the form

of gas. If a cloud is cold enough, the

water vapor freezes to form ice crystals.

At temperatures between about .40° F

(.40° C) and 32° F (0° C), water vapor

crystallizes around bits of dust in the

cloud. At lower temperatures, water

vapor freezes directly into ice crystals.

The ice crystals can stay up in the

clouds. Or, if they are heavy enough,

they can fall to the ground. As they fall

they can clump together with other ice

crystals to form snowflakes. One snowflake

can contain as many as 100 ice

crystals. But some single ice crystals fall

as snow, too.

Snowflake Shapes

The way that ice crystals join together

gives every snowflake a unique design.

Even so, most snowflakes have six

points or six sides. They form seven

basic shapes: stars, needles, dendrites

(having branches), plates, columns,

A green mamba hatches from its

egg. Baby snakes look like small

adult snakes.

A layer of snow covers the ground in a

mountainous region. Like rain, snow is

made of water. But the water in snow is frozen

into crystals of ice.

BRITANNICA STUDENT ENCYCLOPEDIA Snow 115

columns capped with plates, and

irregular (damaged). What shape a

snowflake takes depends on the

temperature and the amount of

moisture in the cloud.

Where Snow Falls

Snow falls in many places that get cold

weather, mainly during winter. In areas

near the North and South poles, snow

covers Earth year-round. Near the equator,

snow falls only in the highest mountain

regions.

Effects of Snow

Snow greatly affects climates and living

things. A cover of snow on the ground

helps to keep the air cold. This happens

because snow reflects, or bounces back,

most of the sun’s heat. However, a snow

cover can also protect small plants from

the effects of severe cold. When snow

melts in the spring, it provides freshwater

for people and animals. But if snow

does not melt for years, it may form

huge slabs of ice, called glaciers.

#More to explore

Climate • Cloud • Crystal • Glacier

•Water

Soccer

Soccer is the world’s most popular team

sport. In most parts of the world the

game is called football or association

football. Both men and women play

soccer in schools, clubs, and on national

and professional teams. In a soccer game

two teams compete to score more

points, which are called goals. The players

move the ball around a rectangular

field, usually by kicking it. A team scores

when it sends the ball into the opposing

team’s goal.

The World Cup soccer tournament is

the world’s most popular sports event.

Every four years teams from many countries

compete for theWorld Cup.

Playing Area and Equipment

Soccer fields vary in size. A field should

be 100 to 130 yards (90 to 120 meters)

long and 50 to 100 yards (45 to 90

meters) wide. Boundary lines called

touchlines mark the sides of the field.

Goal lines mark the ends of the field. A

goal is located at each end of the field.

The goal is a frame that is 8 yards (7.3

meters) wide and 8 feet (2.4 meters)

high. It has a net on the top, sides, and

back. A soccer ball is round and filled

with air.

Snow piles up against a window in Norway.

The crystal structure of snow can be

seen in the small clumps of flakes.

116 Soccer BRITANNICA STUDENT ENCYCLOPEDIA

Playing the Game

Soccer teams are made up of 11 players

each. Each team tries to control the ball

and move it toward the opponent’s goal.

Only one player on each team, the goalkeeper,

can touch the ball with the

hands and arms. The rest of the players

can touch the ball with any part of the

body except the hands and arms. They

usually move the ball with their feet.

Roles of the Players

During a soccer game the players of each

team spread across the field in loose formations.

A formation generally has

front, back, and middle sections.

The front section is the offensive, or

scoring, part of the team. The main

offensive players are called forwards, or

strikers. When a team has the ball, the

forwards try to score goals. A team’s

forwards are usually located closest to

the opponent’s goal.

The back section is mostly defensive—it

protects the team’s goal. Each team has a

goalkeeper in front of its goal. Goalkeepers

try to deflect or catch the opponent’s

shots at the goal. Players called

defenders form a defensive screen

between their goalkeeper and the opposing

team. Defenders try to take the ball

from the other team.

The players in the middle section play

both offense and defense. Midfielders

generally are located between their

team’s forwards and defenders.

Playing Skills

Soccer players move the ball by either

dribbling, kicking, or heading it. A

player dribbles by using very short kicks

to move the ball forward. Dribbling

allows a player to keep control of the

ball while running down the field. Players

use longer kicks to pass the ball to

teammates or to try to make a goal.

Striking the ball with the head is called

heading. Players often head the ball

when receiving long, high passes. Sometimes

they also try to head the ball into

the goal.

When one player has the ball, players on

the opposing team try to take the ball

away from that player. This is called

tackling. In one type of tackle a player

uses the feet to kick or steal the ball

Soccer fields can vary in overall length and width. But penalty areas, goal areas, and

goals always are the same sizes.

BRITANNICA STUDENT ENCYCLOPEDIA Soccer 117

away from an opponent. Another way to

get the ball is to intercept a pass. A

player intercepts a pass by stealing the

ball during a pass between two opponents.

Fouls

Three officials—a referee and two

assistants—control the game. They give

teams penalties when players commit

fouls, or break the rules. After some

fouls the officials award free kicks to the

other team. When a free kick is taken,

all players of the offending team must be

at least 10 yards (9 meters) from the

ball. The officials award penalty kicks

for more serious fouls. A penalty kick is

a free kick at the offending team’s goal.

It is taken from a spot 12 yards (11

meters) from the goal. All players other

than the defending goalkeeper and the

kicker must stand aside.

History

Games like soccer were played in China

more than 2,000 years ago. Similar

games were also played in ancient

Greece, Rome, Japan, and Mexico. But

the modern game of soccer started in

England. In 1863 several English soccer

teams formed the Football Association

(FA). It created the first standard set of

rules for the game.

The FA was an amateur organization,

which means that its players were not

paid. Professional soccer leagues, in

which players were paid, began in the

late 1880s. They formed first in England

and then in other countries. By 1900

people were playing soccer throughout

the world.

In 1904 the Federation Internationale

de Football Association (FIFA) was

formed. FIFA governs the game at the

international level. In 1930 FIFA organized

the firstWorld Cup tournament.

Portugal’s goalkeeper fails to stop France

from scoring a goal on a penalty kick during

the 2006 World Cup.

Mia Hamm of the United States drives to the

goal in a game against Brazil in 1999.

Later that year Hamm led the U.S. team to a

women’s World Cup championship.

118 Soccer BRITANNICA STUDENT ENCYCLOPEDIA

The first women’sWorld Cup was held

in 1991.

Soccer became an official event at the

Olympic Games in 1908. It was the first

team sport to be included in the Olympics.

Women’s soccer became an Olympic

event in 1996.

Soccer is not as popular in the United

States as it is in other parts of the world.

In the 1990s, however, it began to grow

in popularity. In 1994 the United States

hosted theWorld Cup. Two years later a

professional league—Major League

Soccer—was formed. The United States

also hosted theWomen’sWorld Cup in

1999, and the U.S. team won that

championship. In addition, many young

people in the United States enjoy playing

the game.

Socialism

Socialism is a way to organize a society.

It deals mostly with the economy, or the

part of a society that creates wealth. The

goal of socialism is to spread wealth

more evenly and to treat all people fairly.

People have had different ideas about

how to create a socialist society. But

most have agreed that the government,

not individuals, should control at least

some businesses and property.

Beginnings of Socialism

Socialism began as a reaction to the system

called capitalism. In capitalism,

individuals own property, and people

and companies compete with one

another for wealth. Capitalism grew

strong during the Industrial Revolution.

This was a time in the 1700s and 1800s

when many machines were invented and

factories were built. The owners of the

factories grew wealthy. But the workers

worked very hard for little money. Plus,

they were often mistreated.

To create a fairer society, some people

wanted the government to control

industry. The government could then

use its economic power to create a comfortable

life for everyone. This new system

was socialism. Socialists believed

that the ownership of factories and other

property would gradually pass from a

few wealthy people to the workers.

Some socialists did not want to wait for

gradual change. Instead, they wanted

workers to overthrow the capitalist system.

A German scholar named Karl

Marx believed that workers eventually

In 1910 Charles Edward Russell,

an American journalist and

writer, ran for the governor of

New York as a socialist.

BRITANNICA STUDENT ENCYCLOPEDIA Socialism 119

would create an extreme socialist system

known as Communism. In a true Communist

society, there would be no private

property or government. People

would produce and share goods and

other wealth based on their different

abilities and needs.

Socialist Governments

The Russians set up the first Communist

government. They formed a new

country, called the Soviet Union, in

1922. In the 1940s many countries of

eastern Europe also became Communist.

AfterWorldWar II (1939–45) Communists

took control of China, North

Korea, Vietnam, and Cuba. Many African

countries also turned to Communism.

After the war Great Britain, France,

Italy, and Germany adopted some socialist

ideas, too. Their governments took

control of some businesses. They also set

up programs to provide money, health

care, and other services to citizens who

needed them. Even some countries that

rejected socialism—such as the United

States—set up social service programs.

End of Extreme Socialism

By the end of the 1900s extreme socialism

had failed to live up to its promise.

Communist countries tended to have

harsh governments. Their citizens were

also much poorer than those in capitalist

countries. The Communist governments

in the Soviet Union and eastern Europe

collapsed in the 1990s. China remained

Communist but began to allow private

business ownership.

Some governments in Europe, Latin

America, and elsewhere continued to

follow socialist ideas. However, they also

supported capitalism.

#More to explore

Capitalism • Communism

Social Science

The social sciences are fields of study

about human life and behavior. The

social sciences are also known as social

studies or behavioral sciences. People

who study social sciences look at how

people think and act. They also study

how people form groups and relate to

other people.

The main social sciences are anthropology,

economics, political science, psychology,

and sociology. Anthropology is

the study of humans and their cultures

throughout history. Economics is the

study of how people make wealth and

spread it around. Political science is the

A membership card from the socialist organization

called the International Working

Men’s Association shows the signature of

Karl Marx, who was active in the group.

120 Social Science BRITANNICA STUDENT ENCYCLOPEDIA

study of governments. Psychology is the

study of the human mind and human

behavior. Sociology is the study of society,

or the different groups that people

form.

Some people consider other subjects to

be social sciences, too. These subjects

include communications, education,

geography, history, and law.

#More to explore

Anthropology • Economics

• Government • Psychology • Sociology

Society of

Friends

#see Quakers.

Sociology

Sociology is the scientific study of

human societies, or groups. Scientists in

this field are called sociologists. Sociology

is one of the social sciences. The

social sciences deal with human life and

behavior. They also include psychology

and anthropology.

Humans are naturally social beings. This

means that they form groups and enjoy

relating to others. But the rules and

pressures of groups deeply influence

people. A group can cause people to act

differently than they might act outside

the group.

Sociologists study the influence of

groups on human behavior. They study

how humans behave in small groups,

such as families and schools. They study

how humans behave in larger societies,

such as cities and countries. Sociologists

also examine how societies develop and

change.

The work of sociologists helps to explain

the causes of poverty, crime, and other

problems in society. This information is

helpful to lawmakers, business leaders,

Games played in the schoolyard can show

sociologists how children in a society act

with one another.

Social scientists study many types of groups

of people, including the family.

BRITANNICA STUDENT ENCYCLOPEDIA Sociology 121

educators, and others working to

improve human life.

..More to explore

Anthropology • Psychology • Social

Science

Sofia

Population

(2008 estimate)

1,240,790

Sofia is the capital of Bulgaria, a country

in southeastern Europe. It is Bulgaria’s

largest city. Sofia was named after Saint

Sofia Church, which was built in the

city in about the 500s.

Many people in Sofia work for the government

or in tourism or other service

industries. The city is Bulgaria’s main

center of industry and trade. Factories in

Sofia process foods and metals and make

electronics, machinery, and cloth. Engineering

is also a leading industry.

Sofia is an ancient city. People called the

Thracians settled in the Sofia area more

than 2,700 years ago. About 700 years

after that the Romans conquered the

city. The city later became part of the

Byzantine Empire.

The Bulgarians made Sofia part of their

state in AD 809. The Turkish Ottoman

Empire controlled the city from the late

1300s to the late 1800s. Sofia has been

the capital of Bulgaria since 1879.

..More to explore

Bulgaria

Softball

Softball is a sport that has rules similar

to those of baseball. However, softball

has a smaller field and a larger, softer

ball. Also, a softball pitcher throws the

ball with an underhand motion. Both

men and women play softball.

Playing Area and Equipment

A softball field is shaped like a triangle

with one rounded side. This is the same

shape as a baseball field. The field is

divided into an infield and an outfield.

Four bases lie inside the infield. The

The Alexander Nevsky Cathedral

is an Eastern Orthodox church in

Sofia, Bulgaria. It was built in

the early 1900s.

122 Sofia BRITANNICA STUDENT ENCYCLOPEDIA

bases are called home plate, first base,

second base, and third base. They mark

the corners of a square area called the

diamond. The sides of the diamond are

about 60 feet (18.3 meters) long. A

pitcher’s mound rises in the middle of

the diamond. The outfield lies beyond

the infield.

A softball is about 12 inches (30.5 centimeters)

around. The players wear

webbed gloves to catch the ball. To hit

the ball, they use a rounded bat.

Playing the Game

A softball team has nine or 10 players.

During a game two teams take turns

fielding, or playing defense, and

batting, or playing offense. The fielding

team’s pitcher stands on the mound.

The catcher plays behind home plate to

catch the ball. One player plays at each

base, and the others cover the rest of

the field.

The batting team tries to score runs, or

points, against the fielding team. It

sends batters, one at a time, to home

plate. Batters try to hit the ball, which

the pitcher throws toward home plate. If

the batter swings at the ball and misses,

it is called a strike. If the batter does not

swing, the pitch is called either a strike

or a ball, depending on whether it was

good or bad. Three strikes make an out,

or the end of the batter’s turn. Four balls

make a walk, which means the batter

goes to first base. If the batter hits the

ball into the field, he or she begins to

run around the bases.

After the batter hits the ball, the players

in the field try to get the batter out.

They can do this by catching the ball,

touching the batter with the ball, or

getting the ball to first base before the

batter gets there. If the batter reaches a

base without any of these things

happening, the batter is safe. This

player may then move to the next base

when the next batter hits the ball.

When a player on the batting team has

touched all four bases, he or she scores

a run.

The batting team keeps batting until

there are three outs. After both teams

have a turn batting, an inning is finished.

Seven innings make up a game.

At the end of the game, the team with

more runs wins. The teams may play

extra innings to break a tie score.

History

Many people think that softball was

invented in Chicago, Illinois, in 1887.

Men’s and women’s teams soon formed

Playing softball is a popular way

to get exercise and have fun.

In its early

days softball

was known as

kitten ball,

mush ball,

diamond ball,

indooroutdoor,

and

playground

ball.

BRITANNICA STUDENT ENCYCLOPEDIA Softball 123

elsewhere in the United States and in

Canada. The Amateur Softball

Association of America (ASA) was

formed in 1933. The ASA still oversees

softball in the United States. The first

International Softball World

Championships were held in 1965. In

1976 the International Women’s

Professional Softball League was

formed. In 1996 women’s softball was

added to the Summer Olympics.

#More to explore

Baseball • Olympic Games

Soil

Soil is a mixture of minerals and organic

material that covers much of Earth’s

surface. Minerals are bits of rock, and

organic material is the remains of living

things that have died. Soil is not as solid

as rock. It has many small spaces, called

pores, that hold water and air. In some

places on Earth, a thin layer of soil only

6 inches (15 centimeters) thick lies on

top of rock. In other places, though, soil

may be hundreds of feet deep.

The Importance of Soil

Without soil, most life on Earth could

not survive. Soil provides a place for

plants to grow. It holds water in place

for their roots. It contains nutrients, or

food substances, needed for their

growth. Soil also provides a home for

many animals and other living things.

Soil forms slowly. A layer of soil that is 1

inch (2.5 centimeters) thick may take

500 to 1,000 years to form. For this

reason it is important to protect soil

from erosion—being blown or washed

away.

How Soil Forms

The mineral part of soil forms from

rocks. Such forces as wind, water, and

Dark layers of soil lie near the ground’s

surface in the U.S. state of Montana.

Beneath them is glacial till—a mixture of

clay, sand, and rocks that a glacier left

behind when it melted away.

A player pitches the ball during

a women’s softball game at the

Summer Olympics. Unlike in

baseball, softball pitchers throw

the ball with an underhand

motion.

124 Soil BRITANNICA STUDENT ENCYCLOPEDIA

temperature changes break rocks down

into tiny particles, or bits. The smallest

particles are called clay. Medium-sized

particles are called silt. The largest particles

are called sand. Different types of

soil contain different mixtures of clay,

silt, and sand.

The organic part of soil forms when

plants and animals die. Their bodies

decay, or break down, and mix with the

rock particles. The organic material,

called humus, helps to form the pores in

the soil. It keeps the soil soft and loose.

Humus also provides the nutrients used

by plants.

Layers of Soil

Soil is made up of layers. The layers rest

on solid rock, called bedrock. A layer of

broken rock rests on the bedrock. Some

of this rock may have gone into forming

the soil above. The soil above the broken

rock is called subsoil. Subsoil contains

mostly minerals and a small amount of

humus. Only the deepest plant roots

reach the subsoil. The top layer is called

topsoil. Topsoil contains a lot of humus.

It is the layer where plants grow.

#More to explore

Clay • Erosion • Mineral • Plant • Rock

• Sand

Solar Energy

Solar energy is light, heat, and other

forms of energy given off by the sun.

Solar energy can be collected and used

to heat buildings and to make electricity.

Solar Heating

Most solar heating systems capture solar

energy with a device called a flat-plate

collector. The collector is a large plate

of black metal covered with a sheet of

glass. It is usually placed on the roof of

a building. The plate absorbs sunlight

and uses it to heat air or water that

flows through pipes behind it. The air

or water then goes through the

building’s heating or plumbing system.

It can also be held in a storage tank for

later use.

Making Electricity

Devices called solar furnaces and solar

cells can turn solar energy into electricity.

A solar furnace uses the sun’s heat to

make electricity. It has mirrors that focus

large amounts of solar energy into a

small area. A solar furnace can produce

temperatures of up to 3,630° F (2,000°

C). This heat can be used to make

steam. The steam can be used to make

electricity in a power plant.

Solar cells use the sun’s light rather than

its heat. When the sun shines on a solar

The roof of a house has flat-plate collectors

that capture solar energy to heat air or water.

BRITANNICA STUDENT ENCYCLOPEDIA Solar Energy 125

cell, the cell turns the light energy into

electricity. A single solar cell makes only

a little electricity. However, groups of

solar cells can provide electricity for

whole buildings. Solar cells are also used

in a variety of products, including calculators,

watches, electronic toys, and portable

radios.

Benefits and Costs

Solar energy has two big benefits over

fossil fuels (coal, oil, and natural gas).

First, though fossil fuels can be used up,

there is an endless supply of sunlight.

Second, solar energy does not cause pollution,

like burning fossil fuels does.

However, the equipment needed for

collecting and using solar energy is

expensive. The high cost of solar energy

has limited its use.

#More to explore

Electricity • Energy • Heat • Sun

Solar System

The solar system consists of the sun and

everything that orbits, or travels around,

the sun. This includes the eight planets

and their moons, dwarf planets, and

countless comets, asteroids, and other

small, icy objects. However, even with

all of these things, most of the solar system

is empty space.

The solar system consists of the planets that orbit the sun as well as smaller bodies such as

dwarf planets, comets, and asteroids.

126 Solar System BRITANNICA STUDENT ENCYCLOPEDIA

The solar system itself is only a small

part of a huge system of stars and other

objects called the MilkyWay galaxy. The

MilkyWay galaxy is just one of billions

of galaxies that in turn make up the universe.

The Sun

At the center of the solar system is a star

called the sun. It is the largest object in

the solar system. The sun is a very hot

ball of hydrogen and helium gases. It

constantly changes the hydrogen in its

core into helium. This process gives out

huge amounts of energy. Living things

on Earth depend on light and heat from

the sun.

The SolarWind

The gases that surround the sun shoot

out a stream of tiny particles called the

solar wind. It flows outward through the

whole solar system. The solar wind is

what causes auroras, or displays of colored

light in the night sky in parts of

Earth.

The Planets

After the sun, the largest objects in the

solar system are the planets. In order

from closest to the sun, these planets are

Mercury, Venus, Earth, Mars, Jupiter,

Saturn, Uranus, and Neptune. Most of

them orbit the sun in paths shaped like

The Oort Cloud is part of the solar system. It consists of countless small, icy objects. Many

comets were once part of the Oort Cloud.

BRITANNICA STUDENT ENCYCLOPEDIA Solar System 127

circles. Most of the planets have at least

one moon. Scientists used to call Pluto

the ninth planet. But in 2006 scientists

decided to call Pluto a dwarf planet

instead.

Asteroids

Millions of small chunks of metal and

rock called asteroids also orbit the sun.

Most asteroids are found in a ring

between Mars and Jupiter. Small asteroids

regularly fall to Earth or burn up in

the sky as glowing meteors.

Comets

Comets are small chunks of dirt and ice.

Billions of them orbit the sun in very

long paths shaped like ovals. Most comets

are too small or too distant to ever be

seen from Earth. Comets come from

two parts of the outer solar system: the

Kuiper Belt and the Oort Cloud.

Outer Regions

Beyond Neptune lies the Kuiper Belt, a

flat ring of millions of small, icy

objects. These objects orbit the sun at a

very great distance. They are mostly 30

to 50 times farther from the sun than

Earth is.

At the outer reaches of the solar system

is the Oort Cloud. It is a huge cloud of

countless small, icy objects. The Oort

Cloud surrounds the rest of the solar

system.

How the Solar SystemWas

Formed

The solar system formed about 4.7 billion

years ago. It probably started as a

loose cloud of gas and dust. Scientists

think that a force called gravity pulled

parts of the cloud together into clumps.

The largest clump was squeezed together

so tightly that it got very hot. This

clump eventually became the sun. Over

millions of years the other clumps

became the planets. The sun’s strong

gravity eventually pulled the planets into

their orbits. Over time some of the leftover

clumps became asteroids, comets,

and other small, icy objects.

#More to explore

Asteroid • Comet • Galaxy • MilkyWay

• Planets • Sun • Universe

Some Facts About the Planets

Period of Period of Orbit

Rotation Around Sun

Date Diameter (Length of Day) (Length of Year)

Name Discovered (approximate) in Earth Days in Earth Years

Mercury ancient times 3,000 mi (4,900 km) 58.6 0.24

Venus ancient times 7,500 mi (12,100 km) 243 0.62

Earth 7,940 mi (12,780 km) 0.997 1

Mars ancient times 4,200 mi (6,800 km) 1.03 1.88

Jupiter ancient times 89,000 mi (143,000 km) 0.41 11.86

Saturn ancient times 74,900 mi (120,600 km) 0.44 29.4

Uranus 1781 32,000 mi (51,000 km) 0.72 84

Neptune 1846 31,000 mi (50,000 km) 0.67 164

128 Solar System BRITANNICA STUDENT ENCYCLOPEDIA

Solomon Islands

The Solomon Islands is a country in the

southwestern Pacific Ocean. The capital,

Honiara, is on the country’s largest

island, Guadalcanal.

The islands lie east of Papua New

Guinea, in the region called Oceania.

The country includes eight main islands

and hundreds of small islands. The main

islands have many mountains and volcanoes.

Many of the small islands are

made of coral. The country’s climate is

hot, humid, and rainy.

Thick rain forests cover most of the

land. Mangroves and coconut trees grow

along the coasts. Many flowering plants,

including orchids, also grow on the

islands. The country has a wide variety

of birds, butterflies, fish, and reptiles.

Most of the country’s people are

Melanesians, or people native to the

southwestern Pacific islands. There are

many local languages. The different

groups communicate using Pijin, a language

based on English. Most of the

people live in small villages.

The economy is based on farming, logging,

and fishing. Farmers grow coconuts,

sweet potatoes, taro, yams, and

fruits. They raise pigs, cattle, and chickens.

The Solomon Islands produces

palm oil and cocoa.

People have lived on the Solomon

Islands for at least 4,000 years. Spanish

explorers visited the islands in 1568.

Great Britain gained control of the

islands by 1899.

In 1978 the Solomon Islands became

independent from Britain. Since independence,

violence between different

groups has been a serious problem.

..More to explore

Honiara • Oceania

Coral reefs surround some of the

small islands in the Solomon

Islands group.

Facts About

SOLOMON

ISLANDS

Population

(2008 estimate)

517,000

Area

10,954 sq mi

(28,370 sq km)

Capital

Honiara

Form of

government

Constitutional

monarchy

Major towns

Honiara, Noro,

Gizo, Auki,

Tulagi

BRITANNICA STUDENT ENCYCLOPEDIA Solomon Islands 129

Somalia

The country of Somalia in northeastern

Africa is a hot and dry land. Many of

the people follow a nomadic, or wandering,

lifestyle. The capital is Mogadishu.

Geography

Somalia sits on the Horn of Africa, the

most eastern part of the continent. The

Gulf of Aden lies to the north, and the

Indian Ocean lies to the east. On land,

Somalia borders Djibouti, Ethiopia, and

Kenya.

Plains and high, flat areas called plateaus

make up most of the land. Mountains

rise in the northeast. Sand dunes stretch

along the east coast. The Jubba and Shabeelle

rivers flow through the south.

Between those rivers is the richest farmland

in the country.

Somalia is one of the world’s hottest

countries. The southwest and the northwest

receive more rain than the northeast,

which is very dry.

Plants and Animals

Grasses and scattered trees cover much

of the land. About two thirds of the land

is used as pasture, or feeding areas for

livestock. Few plants grow in the dry

northeast.

Somalia’s wildlife includes lions, leopards,

hyenas, foxes, warthogs, ostriches,

and antelope. Hunting has greatly

reduced the numbers of giraffes, zebras,

antelope, hippopotamuses, rhinoceroses,

and elephants.

People

More than half of Somalia’s people are

nomads, or people who move from place

to place while raising livestock. Settled

farmers live mainly in the south. Almost

all the people are Somalis. The Somalis

are divided into many clans, or groups

of related families. Small groups of Ban-

Girls at a school in northeastern Somalia

wear green veils to class.

130 Somalia BRITANNICA STUDENT ENCYCLOPEDIA

tus and Arabs also live in the country.

Nearly everyone is Muslim.

Somali and Arabic are the national languages.

Some people also speak English

or Italian. The Somali language did not

have a written form until 1973.

Economy

Somalia is one of the poorest countries

in the world. Its economy is based on

livestock raising and farming. Sheep,

goats, camels, and cattle are the main

livestock. Farming is possible on only a

tiny percentage of the land. The main

crops include bananas, sugarcane, sorghum,

corn, cassava, cotton, and sesame

seeds. Somalia sells live animals,

bananas, fish, animal hides, charcoal,

and scrap metal to other countries.

History

The coasts of Somalia were probably

part of an ancient land called Punt.

Between the 600s and 900s Arabs and

Persians set up trading posts along the

coasts. By the 900s Somali nomads had

entered the area.

European Rule

Europeans explored the region in the

1800s. In 1884 the British took over a

section in the north, which they called

British Somaliland. Italy soon took over

several regions in the northeast and

along the southern coast. The land

claimed by Italy was known as Italian

Somaliland. In 1960 Italian Somaliland

and British Somaliland gained independence.

Together they formed the new

country of Somalia.

CivilWar

In 1969 the military took over Somalia’s

government. In January 1991 rebels

overthrew the military government. The

country then split into a number of

regions, each controlled by a clan or a

group of clans. In May 1991 the region

that used to be British Somaliland

declared independence as the Republic

of Somaliland. Civil war broke out as

the clans fought for territory. In 1998

the northeastern part of Somalia, known

as Puntland, also set up a government of

its own.

A new Somali government formed outside

the country in 2004. However,

fighting continued inside Somalia.

..More to explore

Mogadishu • Nomad

Somalia is a very poor country.

Most of the land is not good for

growing crops. Many of the

people live in small villages and

raise livestock.

Facts About

SOMALIA

Population

(2008 estimate)

8,956,000

Area

246,000 sq mi

(637,000 sq km)

Capital

Mogadishu

Form of

government

Transitional

government

Major cities

Mogadishu,

Hargeysa, Kismaayo,

Berbera,

Marka

BRITANNICA STUDENT ENCYCLOPEDIA Somalia 131

Songbird

Almost half the species, or types, of bird

in the world are songbirds. The 4,000

species of songbird all belong to one

huge scientific group. Many types sing

beautiful and complex songs. However,

not all songbirds sing much or have

pleasant-sounding voices. What they

have in common are highly developed

vocal organs. Some well-known songbirds

include canaries, cardinals, robins,

blackbirds, bluebirds, nightingales, sparrows,

finches, larks, swallows, and

thrushes.

Birds of this large, varied group can be

found nearly all over the world. They

live on many different types of land.

Physical Features

Songbirds are typically about 5 to 8

inches (12.5 to 20 centimeters) in

length, though some are larger or

smaller. The structure of their feet allows

them to perch on branches. On each

foot, three toes point forward, and one

toe points backward.

The syrinx, or song box, is the organ in

a bird’s chest that produces sound. A

bird sings by sending air through its

song box. Songbirds have very complex

song boxes and several sets of tiny

muscles to control them. Some songbirds

make mostly short, simple calls,

such as the “caw” of some crows. Other

types also produce long songs that are

musical and varied. Some songbirds,

such as mockingbirds, even imitate the

songs of other birds.

Behavior

Songbirds sing for a variety of reasons,

especially during the breeding season.

Their songs show that they are ready to

mate. Songbirds may also make a variety

of calls to communicate with their mates

and young. Many songbirds sing to

announce that a certain territory is

theirs. They sing at different spots along

the edges of their land to try to prevent

other birds from taking over it. In many

species only the male sings complicated

songs.

Different types of songbird eat different

foods, including insects, fruits, and

seeds. Many types are known for building

complex nests.

#More to explore

Bird • Blackbird • Bluebird • Canary

• Cardinal • Crow • Mockingbird

• Nightingale • Robin • Sparrow

Songhai Empire

The Songhai Empire controlled trade in

much of western Africa during the

1400s and 1500s. The empire was cen-

The grasshopper warbler is a songbird of

Europe and Asia.

132 Songbird BRITANNICA STUDENT ENCYCLOPEDIA

tered in what is now central Mali. It

eventually extended west to the Atlantic

coast and east into what are now Niger

and Nigeria. Songhai grew rich trading

gold and salt up and down the Niger

River and across the desert lands of the

Sahara.

Songhai people had settled in the city of

Gao in about AD 800. The Mali Empire

took over Gao in 1325. After 50 years

the Songhai won back their independence.

A great Songhai warrior named

Sonni !Ali took power in 1464. He built

the Songhai Empire by conquering Timbuktu,

Jenne, and other nearby cities.

Most Songhai people raised herds of

animals for a living. However, many

Songhai lived in big cities. All the cities

were centers of trade on the Niger River.

Gao was the capital. It had about

100,000 people. Timbuktu had at least

80,000 people. It was the site of a

famous university. While most of Songhai’s

herders continued to follow traditional

religions, Islam became the

religion of the cities.

The empire prospered until the late

1500s. Then an army from Morocco, a

kingdom on Africa’s northwestern coast,

swept down over the Sahara. By 1591

the Moroccans had easily captured the

cities because they had better weapons

than the Songhai had. The people outside

the cities continued to fight the

Moroccans, but they could not bring

back the empire.

#More to explore

Mali • Mali Empire

Sorghum

Sorghum plants belong to the grass family,

as do corn and other grains. Sorghum

is one of the major grains grown

in Africa. Farmers also grow sorghum in

Hundreds of seeds are bunched

together on a sorghum plant.

BRITANNICA STUDENT ENCYCLOPEDIA Sorghum 133

the Americas, Asia, southern Europe,

and Australia.

Sorghum plants often grow to a height

of 2 to 8 feet (0.5 to 2.5 meters). Some

may grow to be 15 feet (4.5 meters) tall.

Clusters of flowers grow at the top of

each sorghum plant. The clusters produce

800 to 3,000 seeds.

Farmers grow and harvest sorghum for

these starchy seeds. The seeds are a cereal

grain like wheat, rye, oats, and rice.

People grind them to make cakes,

breads, and porridge, which is a dish

similar to oatmeal. People also use sorghum

plants to feed animals, to make

hay, and to make brooms and brushes.

In some types of sorghum the stems

contain sweet juices. In the southern

United States and in southern Africa

farmers grind sorghum stems to collect

the juices. They then boil the juices to

make a thick, sweet syrup, also called

sorghum.

#More to explore

Grain • Grass • Seed

Soto, Hernando

de

#see De Soto, Hernando.

Sound

A sound is anything that can be heard.

Music, the barking of a dog, the wailing

of a siren, and the voice of a friend are

all sounds.

What Makes Sound

For a sound to be made and heard, three

things need to happen. First, an object

vibrates. A vibrating object makes tiny,

very fast back-and-forth movements. For

example, when a musician strums guitar

strings, they vibrate. The vibration

moves the surrounding air and produces

waves of sound.

Second, the sound waves pass into a

medium. A medium is any substance

through which the waves can travel.

Sound waves may travel through many

mediums. These include air, water, and

solid objects. Sound waves pass through

mediums in all directions.

Third, some kind of receiver, such as the

ear of a person, picks up the sound

waves. The ear changes the sound waves

into signals that travel to the brain. The

brain understands these signals as sound.

Speed of Sound

The speed of sound varies depending on

what medium it is traveling through. In

air at a temperature of 70° F (21° C)

sound travels at a speed of 1,129 feet

(344 meters) per second. This means

Sorghum

grows better in

hot and dry

conditions

than most

other grains.

Sound waves travel through air from a

source to a receiver.

134 Soto, Hernando de BRITANNICA STUDENT ENCYCLOPEDIA

waves to loudspeakers to reproduce the

original sound.

Recording devices can preserve sound in

a number of formats. The earliest formats

were phonograph records and magnetic

tape. A phonograph record has a

groove with patterns cut into it that

represent the waves of sound. Magnetic

tape represents sound with wavelike

patterns of magnetized particles.

Most sound-recording devices today are

digital devices. They store sound as a

long series of numbers that describe the

sound waves. On CDs this information

is stored as a pattern of tiny pits, or

holes, that are created and read by a laser

beam. The digital information can also

be stored in personal computers or in

portable devices called digital audio

players.

History

In 1877 Thomas Edison, a U.S. inventor,

made the first device for recording

and playing back sound. It was a phonograph

made up of a cardboard cylinder

wrapped in tinfoil. It recorded sound

with a small needle that formed a track

in the tinfoil. Ten years later an inventor

named Emil Berliner improved Edison’s

device by replacing the cylinder with a

flat phonograph record. Berliner also

invented a way to make copies of

records. By the early 1900s records had

become a popular form of home entertainment.

German engineers developed tape

recorders in the 1930s and 1940s. U.S.

and British researchers improved on the

German equipment in the late 1940s.

By the early 1980s music cassette tapes

had become more popular than phonograph

records.

Also in the early 1980s compact discs

were introduced. Since then CDs have

mostly replaced records and cassettes. At

first people could only buy prerecorded

CDs to play on a CD player. But in the

1990s recordable CDs were introduced.

This technology allowed people to make

their own CDs using a computer or a

separate CD recorder. The first digital

audio players appeared in the late 1990s.

#More to explore

Compact Disc • Edison, Thomas Alva

• Sound

Two people can listen to a portable MP3

player if they share a set of earphones. A

portable MP3 player is a digital audio player.

136 Sound Recording BRITANNICA STUDENT ENCYCLOPEDIA

South Africa

The country of South Africa covers the

southern tip of Africa. It has three capital

cities: Pretoria (Tshwane), Cape

Town, and Bloemfontein.

Most of South Africa’s people are black.

However, white people controlled the

government until 1994.

Geography

South Africa has a long coastline on the

Atlantic and Indian oceans. To the

north South Africa borders Namibia,

Botswana, Zimbabwe, Mozambique,

and Swaziland. South Africa also

surrounds the tiny kingdom of Lesotho.

Most of South Africa is a plateau, or

raised flat area. Mountains separate the

high plateau from lower plains along the

coast. The highest mountain range is the

Drakensberg, in the east. The Kalahari

and Namib deserts cover parts of the

west. The main rivers in South Africa are

the Orange and the Limpopo.

Most of South Africa has a dry climate

with warm summers and cool winters.

Drought is a common problem.

Plants and Animals

Grasslands with scattered trees cover

much of South Africa. Many types of

flowering plants grow in the southwest.

The dry parts of the west have shrubs

and bushes that can survive with little

rain. South Africa’s few forests grow in

mountain valleys and along stretches of

the coast.

South Africa has limited numbers of

lions, elephants, rhinoceroses, hippopotamuses,

and antelope. The country’s

large animals live mainly in wildlife

parks.

People

Black Africans make up about three

fourths of South Africa’s population.

They belong to a number of groups,

including the Zulu and the Xhosa. Each

South African schoolgirls enjoy themselves

while on a field trip in the Western Cape

Province, South Africa.

BRITANNICA STUDENT ENCYCLOPEDIA South Africa 137

of the African groups has its own

language.

South Africa has three main minority

groups: people of European descent,

people of mixed ancestry, and people of

Asian descent. The people of European

descent speak either Afrikaans (a language

related to Dutch) or English. The

Afrikaners (those who speak Afrikaans)

have mainly Dutch, French, and German

roots. The English speakers have

mainly British ancestors. The people of

mixed descent have African, Asian, and

European roots. The ancestors of the

people of Asian descent came mainly

from India.

Most South Africans are Christians.

More than half of the people live in cities,

mainly in the east.

Economy

Services such as banking and tourism are

key parts of South Africa’s economy.

Mining and manufacturing are also very

important. South Africa is a top producer

of many minerals, including gold,

platinum, and chromium. It also mines

coal and diamonds. Factories make iron

and steel, food products, machinery,

chemicals, cars, and other goods.

South Africa’s major crops include corn,

wheat, sugarcane, citrus fruits, and potatoes.

Farmers also grow grapes to make

wine. Meat, wool, and milk are other

important farm products.

History

About 10,000 years ago the San and the

Khoekhoe peoples roamed southern

Africa. About 2,000 years ago peoples

who spoke Bantu languages settled in

the region. The Bantu peoples were the

ancestors of most of the blacks in South

Africa today.

European Settlement

The Portuguese sailed around the southern

tip of Africa in the late 1400s. In

1652 the Dutch set up a colony on the

southwest coast. They slowly expanded

their settlements, planted crops, and

raised livestock. They became known as

Boers, meaning “farmers.” (Later they

became known as Afrikaners.) As the

Boers moved east, they fought with

many African peoples, especially the

Xhosa.

By 1806 the British had taken over the

Dutch settlement. To escape British rule,

many Boers moved north during the

1830s and 1840s. Their move is known

as the Great Trek. In the 1850s the

Boers set up two states in the northeast:

the South African Republic (or Transvaal)

and the Orange Free State.

A prince of the Zulu people of South Africa

wears traditional clothing.

Facts About

SOUTH AFRICA

Population

(2008 estimate)

48,783,000

Area

470,693 sq mi

(1,219,090 sq

km)

Capitals

Pretoria (executive),

Bloemfontein

(judicial),

Cape Town

(legislative)

Form of

government

Republic

Major cities

Cape Town, Durban,

Johannesburg,

Pretoria,

Port Elizabeth

138 South Africa BRITANNICA STUDENT ENCYCLOPEDIA

British Rule

The British expanded their territory,

called the Cape Colony, across the

southern tip of Africa. They then tried

to take over the Boer states. From 1899

to 1902 the British and the Boers fought

the BoerWar. After winning the war,

the British made the Boer states into

British colonies.

In 1910 all the British colonies in southern

Africa united. They formed a new,

independent country called the Union

of South Africa.

Apartheid

Whites controlled the new government

of South Africa. They passed laws that

separated the population by race. This

system of separation became known as

apartheid. The word means “separateness”

in the Afrikaans language. The

system also gave the white minority

nearly all the political power, most of

the land, and the best jobs.

In 1912 blacks and people of mixed

ancestry formed a political group that

became known as the African National

Congress (ANC). The ANC held nonviolent

protests against the white government.

In 1960 police shot hundreds

of protesters in Sharpeville, South

Africa. In response, the ANC turned to

bombings and other acts of violence to

protest apartheid. Some ANC leaders,

including Nelson Mandela, went to jail.

A New South Africa

In 1990 a new South African president,

F.W. de Klerk, announced that apartheid

would end. The government released

Mandela from prison and threw out the

apartheid laws. South Africans of all

races voted in elections in 1994. Mandela

became the country’s first black

president.

#More to explore

African National Congress • Apartheid

• Bloemfontein • Cape Town • Mandela,

Nelson • Pretoria

1652 1806 1902 1910 1912 1990 1994

The Dutch settle

in South Africa.

The British take

over the Dutch

colony.

The British win

the Boer War.

The Union of

South Africa is

formed.

The African

National

Congress is

founded.

Nelson

Mandela is

released from

prison.

South Africa

elects its first

black

president;

apartheid ends.

T I M E L I N E

BRITANNICA STUDENT ENCYCLOPEDIA South Africa 139

South America

South America is the world’s fourth

largest continent. The countries of

South America are also part of a larger

cultural region known as Latin America,

in which most of the people speak Spanish

or Portuguese.

Land and Climate

Most of the continent is covered by

rugged mountains and plateaus, which

are high, flat lands. In the north are the

Guiana Highlands. The Brazilian

Highlands, another group of mountains

and plateaus, covers more than half of

Brazil. This amounts to about a quarter

of South America. The Andes Mountains

lie along the western edge of the

continent. They are one of the most

impressive ranges in the world. In

eastern Peru and western Bolivia is a

great plateau called the Altiplano. In

the far south is a region of vast plateaus

known as Patagonia.

South America has several rivers that

form large basins. These basins are generally

flat and low-lying. The largest is

the Amazon basin. It includes parts of

Brazil, Venezuela, Colombia, Ecuador,

Peru, and Bolivia. The Parana and

Orinoco rivers also form basins.

The Amazon River is the most extensive

river system in the world. Other major

rivers include the Orinoco, Paraguay,

Parana, and Uruguay. Parts of the Andes

have many lakes. In addition, vast

marshes are found in many low-lying

parts of the continent.

Most of South America has a tropical

climate. In the tropical rain forests of the

north and east, it is hot and rainy yearround.

Parts of central South America

have generally warm summers and cool

winters, with plenty of rain. There are

also several desert areas, including the

coast of Peru and northwestern Argentina.

In the far southern parts of Argentina

and Chile and high in the

mountains, it is mostly cold and rainy

year-round.

Plants and Animals

The Amazon River basin contains the

world’s largest area of tropical rain forest.

Many types of tree are found there.

However, people are rapidly destroying

large areas of rain forest. This is mainly

because settlers are trying to use the land

for agriculture or to build roads and

houses. Savannas, which are grasslands

with some trees, are typical in central

Rugged mountains form a dramatic backdrop

for the city of Ushuaia, in the province

of Tierra del Fuego, Argentina.

140 South America BRITANNICA STUDENT ENCYCLOPEDIA

BRITANNICA STUDENT ENCYCLOPEDIA South America 141

Venezuela and Brazil. The coastal deserts

of Chile and Peru have little vegetation.

Two of the better-known animals of the

Andes are the llama and the alpaca.

Other mammals include several cats

(especially the jaguar and puma), deer,

bears, wolves, foxes, and raccoons.

Mammals such as monkeys, porcupines,

armadillos, anteaters, sloths, and a wide

variety of rats, mice, and bats live in the

rain forests. South America has more

than a thousand kinds of bird. Hummingbirds,

parrots, toucans, woodpeckers,

and raptors can be found in

different regions of the continent. The

Andean condor is one of the largest flying

birds. The Humboldt penguin is

found in several spots along the coasts.

There are also numerous types of fish

and reptile, including many lizards and

snakes.

People

Various groups of Native Americans, or

American Indians, were the continent’s

original inhabitants. Today the population

is a blend of several distinct groups:

Native American, European (mostly

Spanish and Portuguese), and African.

About 40 percent of the people in South

America are white. Another 40 percent

have mixed ancestry, either as mestizos

(of white and Indian descent) or mulattoes

(of black and white descent or black

and Indian descent).

Most South Americans speak Spanish or

Portuguese. Many Indian languages,

such as Quechua and Aymara, are also

spoken. In some areas people speak

English, French, or Dutch. Most South

Americans are Roman Catholic. In some

countries people blend Catholicism with

traditional elements from African and

Indian religions.

In general, children in South America

must attend primary school. However,

in some remote areas people do not have

access to schools. Nearly all South

American cities have hospitals, but doctors

and advanced medicines are not

always available. The greatest health

problems are in the rural districts, particularly

in the low plains and river valleys

of the tropics. There insects carry

diseases such as malaria, and impure

water is common. People who live in the

Misty spray rises from Iguacu Falls to create rainbows. The waterfalls are located on a

stretch of the Iguacu River along the border between Brazil and Argentina.

142 South America BRITANNICA STUDENT ENCYCLOPEDIA

crowded, poorer city neighborhoods also

have a higher risk of health problems.

Economy

For many years the economies of most

South American countries were not well

developed. Most people worked in agriculture,

and there was not much industry.

The countries also relied on foreign

aid. But in the late 1900s many South

American countries began to try to

improve their economies by increasing

manufacturing.

South America has great mineral wealth.

It has about one fifth of the world’s iron