The state Capitol in Charleston, West Virginia,
faces the Kanawha River.
BRITANNICA STUDENT ENCYCLOPEDIA Chavez, Cesar 83
ers in the United States by organizing
them into a labor union.
Cesar Estrada Chavez was born on
March 31, 1927, near Yuma, Arizona.
During the Great Depression of the
1930s his family became migrant farmworkers
in California. By age 15 Cesar
was working full-time in the fields. DuringWorldWar
II he served in the U.S.
Navy.
In 1952 Chavez joined a group that
helped Hispanic people in California
and encouraged them to vote. In 1962
Chavez and Dolores Huerta founded a
labor union called the National Farm
Workers Association. In 1971 the union
became known as the United Farm
Workers of America (UFW).
Chavez led protests to call attention to
the problems of migrant workers. In the
mid-1960s he launched a strike by California
grape pickers that lasted five
years. During the strike Chavez got
people across the country to stop buying
California grapes. By 1970 most grape
growers had signed contracts that
improved wages and benefits for their
workers. Chavez also led battles against
lettuce growers and other farm businesses.
Chavez served as president of the
UFW until his death on April 23, 1993.
#More to explore
Hispanic Americans • Labor
Cheetah
The cheetah is the fastest land animal on
Earth. This spotted member of the cat
family can sprint faster than 70 miles
(112 kilometers) per hour. The cheetah’s
scientific name is Acinonyx jubatus.
Where Cheetahs Live
Cheetahs live in the wild in scattered
parts of central, eastern, and southern
Africa. A small number of wild cheetahs
live in Iran. Most cheetahs live in grasslands
and dry, open areas.
Physical Features
Small black spots cover most of the
cheetah’s sandy yellow fur. The belly is
white, and the tail is marked with dark
Cesar Chavez
A cheetah sprints through the grass in Kenya.
84 Cheetah BRITANNICA STUDENT ENCYCLOPEDIA
rings. Black lines run from the eyes to
the corners of the mouth.
The cheetah measures about 6.5 feet (2
meters) long, from the head to the tip of
the tail. It is a slender mammal that
weighs about 75 to 120 pounds (34 to
54 kilograms). Males tend to be larger
than females.
A cheetah’s body is built for speed. Long
legs allow the cheetah to take big strides.
Hard paws and exposed claws help it to
grip the ground. The cheetah is the only
kind of cat that cannot pull its claws
completely back.
Behavior
Cheetahs live alone or in small groups.
They hunt small animals, mainly
during the day. After creeping up on an
animal, a cheetah sprints at it from a
few hundred feet away. The cheetah can
keep up the chase for only a short time
before tiring. When the cheetah does
catch its prey, it trips the animal and
bites into it.
Life Cycle
About three months after mating, a
female cheetah gives birth to two to
eight cubs. Cheetah cubs stay with their
mother for more than a year while they
learn to hunt. Some cheetahs in zoos
have reached the age of 19, but most do
not live that long.
Cheetahs and Humans
The ancient Egyptians and some rulers of
India and Europe tamed cheetahs. They
used the animals for hunting.Other
peoples hunted cheetahs for their fur.
Eventually, wild cheetahs disappeared
from India and many other places.Today
cheetahs are in danger of dying out
completely.Human settlements have
taken over much of their land.
#More to explore
Cat • Endangered Species • Mammal
Chemical
Element
A chemical element is a basic substance.
It cannot be broken down into simpler
substances by ordinary chemical processes.
Chemical elements are the building
blocks for all matter—that is,
everything that takes up space in the
universe. They are sometimes just called
elements.
There are 92 chemical elements found
in nature. Scientists have created more
than 20 additional elements. Some
elements are much more common than
others. One common element is
nitrogen. It is the major element in air.
The elements combine to form
substances called chemical compounds.
For example, water is a chemical
compound. It is formed by the
combination of the elements hydrogen
and oxygen.
Element Symbols
Every element has a symbol. The symbol
for some elements is the first letter of its
name. For example, H is the symbol for
hydrogen and O is the symbol for oxygen.
Other elements have a symbol with
Only two
chemical elements
are
liquid at room
temperature.
They are
bromine (Br)
and mercury
(Hg).
BRITANNICA STUDENT ENCYCLOPEDIA Chemical Element 85
two letters. For example, He is the symbol
for helium and Cl is the symbol for
chlorine.
Elements and Atoms
The smallest unit of an element is called
an atom. Each element is made up of
only one type of atom. Atoms, in turn,
are made up of tiny particles, or bits,
called protons, neutrons, and electrons.
All atoms of an element have the same
number of protons. This number is
called the atomic number of the element.
For example, the atomic number
of hydrogen is 1 because a hydrogen
atom has one proton.
Periodic Table
In 1869 a Russian scientist named
Dmitry Mendeleyev grouped the elements
in a table. It is called the periodic
table. The periodic table arranges the
