Britannica Student Encyclopedia - 2010

Development of Modern Aviation

After the war people began to use planes

for commercial purposes, including

delivering mail. Pilots also began to

experiment with seeing how far they

could fly. A U.S. airmail pilot named

Charles Lindbergh became famous in

1927 for making the first solo flight over

the Atlantic Ocean.

Jet-powered aircraft were introduced on

a small scale duringWorldWar II

(1939–45). After the war jet planes were

improved and came into wide use.

Regular passenger jet services across the

Atlantic were started in 1958. Today

passenger jets fly people all around the

world every day.

Air Travel Safety

Airline safety became an important issue

in the second half of the 20th century.

In the United States a government

agency called the Federal Aviation

An early airplane flies over Chicago,

Illinois, in 1911.

Only a few

experimental

airplanes have

used rocket

engines. A

rocketpowered

airplane

called

the X-15 set

records for

speed and

height of

flight.

BRITANNICA STUDENT ENCYCLOPEDIA Airplane 57

 

Administration (FAA) was created in

1958 to monitor aircraft and to investigate

accidents. The FAA also operates

the air traffic control system, which

keeps planes out of each other’s way.

Human error, equipment failure, and

weather can cause accidents. But flying

is still far safer than traveling by car.

#More to explore

Balloon • Glider • Helicopter •Wright,

Wilbur and Orville

Airship

The large aircraft that are often seen

floating over sporting events are commonly

known as blimps. These are actually

a type of lighter-than-air craft called

an airship. Airships were developed from

principles of ballooning. Like balloons,

they are filled with a gas that allows

them to float in the air. Unlike balloons,

airships are driven by engine-powered

propellers and steered with rudders. For

this reason they are also called

dirigibles—after the French word

diriger, meaning “to steer.”

Most airships are long and cigar-shaped.

Some airships have a rigid frame supporting

the craft’s surface fabric. Nonrigid

airships are simply big balloons

that rely on the gas to keep their shape.

Nonrigid airships are also known as

blimps. The main section of an airship is

filled with a gas that is lighter than air.

Helium is the most commonly used gas.

A car, or gondola, suspended below the

gas balloon holds the airship’s crew and

passengers.

Airships rely on several different features

to enable them to fly. The gas inside the

ship lifts the craft into the air. Engines

then propel the craft forward. The pilot

uses a rudder to steer the craft. Most of

the ship is filled with the lighter-than-air

gas. There are also compartments filled

with normal air. The pilot can make the

ship go up or down by controlling the

amount of air in these compartments.

The first propeller-driven airship flew in

1852 in France. Its engine was powered

by steam. The first rigid airship, with a

body made of aluminum, was built in

Germany in 1897. Ferdinand von Zeppelin,

the famous German builder, completed

his first rigid airship in 1900.

Akimel O’odham

#see Pima.

Akmola,

Kazakhstan

#see Astana.

A colorful airship flies over Dodger Stadium

in Los Angeles, California.

58 Airship BRITANNICA STUDENT ENCYCLOPEDIA

 

Aksum

Aksum, or Axum, was a powerful trading

empire that flourished in northeastern

Africa hundreds of years ago. Aksum

also was the name of the kingdom’s

capital. It remains a city in northern

Ethiopia.

Aksum’s location between the Red Sea

and the Nile River helped to make it

one of the most important and wealthy

trading centers of its day. The items that

moved in and out of its ports included

ivory, hippopotamus hides, perfumes,

gold, and animals.

The kingdom was also known for its

architecture. Still standing in the central

square of the city of Aksum are some of

the carved granite obelisks made in the

kingdom. An obelisk is a tall, thin pillar

with a pyramid at the top. (TheWashington

Monument is an obelisk.) Some

Aksum obelisks may have marked

underground tombs of the kingdom’s

rulers.

Aksum expanded as it grew more powerful.

In the AD 300s Aksum conquered

the kingdom of Kush to the north.

Aksum’s rulers then pushed west across

the Red Sea into southern Arabia. In the

600s and 700s the kingdom’s hold

weakened as the Muslim Arabs emerged

as a power.

The people had been Christian since

the 300s. The Arabs allowed them to

keep the Christian religion because they

had once given refuge to followers of

Islam’s founder, the prophet

Muhammad. Today Aksum is

considered a holy city of the Ethiopian

Orthodox church.

#More to explore

Arabian Peninsula • Eastern Orthodox

Churches • Ethiopia • Islam • Kush

• Muhammad

One of the obelisks from the kingdom of

Aksum stands in the modern city of the

same name.

BRITANNICA STUDENT ENCYCLOPEDIA Aksum 59

 

Alabama

The state of Alabama is located

in the center of the Deep South

of the United States. Because of its location,

the land that is now Alabama

played a role in many of the major conflicts

that shaped the United States.

These included battles with Native

Americans over control of the area, the

American CivilWar, and the civil rights

movement of the 1960s. Montgomery is