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
