German noblemen in various cities. His
first major position was as the official
organist for a duke atWeimar. Later he
also became director of the dukes
orchestra. His duties included composing
a sacred cantataa type of music for
use during church servicesevery
month.
In 1723 Bach became the director of
church music for the city of Leipzig.
During his early years in this job, he
composed many cantatas, sometimes up
to one per week. At Leipzig he also
directed an orchestra off and on from
1729 into the early 1740s. Bach died in
Leipzig on July 28, 1750.
During his lifetime Bach was known
mainly for his skill as a musician. After
his death his compositions were mostly
forgotten until the early 1800s. Then
people began to rediscover his works.
Today the music of Bach is highly
acclaimed and is performed frequently.
#More to explore
Classical Music Musical Instruments
Orchestra
A painting from 1720 shows Johann
Sebastian Bach.
4 Bach, Johann Sebastian BRITANNICA STUDENT ENCYCLOPEDIA
Bacteria
Bacteria are small organisms, or living
things, that can be found in all natural
environments. They are made of a single
cell. Most bacteria can be seen only with
a microscope.
Bacteria do not have most of the structures
found in the cells of other organisms.
They are much simpler and
smaller than all other cells of living
things.
Bacteria take in food and send out waste
through their cell walls. Most bacteria
reproduce by dividing down the middle
to form two separate cells. These each
divide again to form a total of four cells.
Through this process, billions of bacteria
may form from a single bacterium in
only 24 hours.
Bacteria that cause diseases can get into
the human body through the nose, the
mouth, and cuts in the skin. Once
inside, these bacteria quickly reproduce
and cause illness, called an infection.
The infection may result from the bacteria
themselves or from their poisonous
waste products, called toxins. Luckily,
the immune system of the human body
can fight these threats.
Sometimes the immune system needs
help in fighting off bacteria. Doctors
may inject dead or weakened bacteria
into the human body. This is called a
vaccine. A vaccine prepares the body to
fight off the same bacteria in the future.
Doctors may also use medicines called
antibiotics to kill bacteria in the body.
#More to explore
Antibiotic Cell Immune System
Vaccine
Badger
Badgers are mammals known for their
powerful digging. They are related to
weasels, skunks, otters, and mink.
Badgers live in many habitats, including
grasslands and forests. There are eight
species, or types, of badger. The American
badger lives in the western part of
North America. The Eurasian badger
can be found in Europe and Asia. The
other types live in Southeast Asia. They
include hog badgers, ferret badgers, and
stink badgers.
Badgers are heavily built animals with
short legs. The different species range
from 13 to 32 inches (33 to 81 centimeters)
long, not including the tail. They
Most bacteria are so small that they can be
seen only by using a microscope. This bacteria
sample has been magnified 2,000
times.
Scientists have
found remains
of bacteria
that are more
than 360 million
years old.
BRITANNICA STUDENT ENCYCLOPEDIA Badger 5
are about 9 to 12 inches (23 to 30 centimeters)
high. The American badger
sometimes looks wider than it is high.
Most badgers have gray or brown fur.
Many types have black-and-white marks
on the face and back.
Badgers have strong front feet with
heavy claws that are excellent for digging.
Badgers dig to make underground
homes called burrows. They may also
dig to find small animals such as squirrels,
mice, and rabbits to eat. Many
kinds eat insects, lizards, birds, and
plants, too. Badgers feed mainly at
night.
Badgers are strong for their size. They
can fight fiercely when threatened. All
badgers have scent glands near the tail.
Like skunks, stink badgers shoot a foulsmelling
liquid from these glands at
their enemies.
..More to explore
Mammal Mink Otter Skunk
Weasel
Baghdad
Population
(2007
estimate), urban
area,
5,054,000
Baghdad is the capital of the Middle
Eastern country of Iraq. It is also Iraqs
largest city. Baghdad lies on both banks
of the Tigris River.
Most of Iraqs industries are located in
and around Baghdad. At one time the
city produced a wide variety of goods,
including cloth, furniture, chemicals,
and electrical equipment. The economy
of the city was disrupted by wars in the
late 20th and early 21st centuries.
People have lived on the site of Baghdad
for some 4,000 years. In AD 762 an Arab
Muslim ruler moved the capital of his
large empire there. Baghdad reached its
greatest power in the late 700s and early
800s. It also became a center of learning.
In 1258 the Mongols captured Baghdad.
Later several other foreign powers
invaded the city.
In 1921 Iraq became an independent
country with Baghdad as its capital. The
city began to grow again in size and
importance.
Iraqs long war with Iran in the 1980s
hurt Baghdads development. During
The American badger is usually found in
open, dry areas of western North America.
Like other badgers it has large front claws
that it uses for digging.
6 Baghdad BRITANNICA STUDENT ENCYCLOPEDIA
the Persian GulfWar of 1991, the
United States and its allies dropped
bombs on the city. Baghdad suffered
further damage when forces led by the
United States invaded the city in 2003.
#More to explore
Iraq
Baha#i Faith
In the middle of the 1800s a religion
called the Baha#i faith started in what is
now Iran. It later spread around the
world. Its followers, called Baha#is, seek
to bring together all people in one religion.
Beliefs and Practices
Baha#is believe that all religions are one
and all people are one. They also believe
that God is beyond understanding. They
teach that people should worship God
and try to make the world a better place.
At services, members listen to readings
from the scriptures of all religions.
Baha#is have no priests or special ceremonies.
There are rules about prayer
and fasting, however. Also, a person is
supposed to marry only once and should
not use alcohol or tobacco.
History
A man named Mirza !Ali Mohammad
started a group called the Babi in Persia
(now Iran) in 1844. He believed that a
new prophet, or messenger of God,
would soon appear. Muslim leaders and
the government opposed his ideas. He
was arrested, and in 1850 he was killed.
One of the first Babis was Mirza
Hoseyn !Ali Nuri. After he joined the
group, he called himself Baha# Ullah.
He was arrested in 1852. While in jail,
he realized that he was the new
prophet. In 1853 he was released and
sent to Iraq. He led the Babi
community there. The Babis who
believed that he was the new prophet
were called the Baha#is.
Baha# Ullah died in 1892. After his
death, his oldest son led the group. He
helped spread the faith to North
America, Europe, and other continents.