122 Electronics BRITANNICA STUDENT ENCYCLOPEDIA
tal electronics. A digital camera is an
example. It changes a picture into many
tiny dots and uses electric signals to create
numbers that describe each of the
dots. Another digital electronic product,
such as a computer or a printer, can also
read those numbers. They can use the
numbers to re-create the picture and
print it or display it on a computer
screen.
Electronic Devices
Most electronic devices, including computer
chips and transistors, are made
from silicon. Silicon is a type of material
called a semiconductor. A semiconductor
lets electricity flow through it only
under certain conditions. This property
makes it useful for controlling the flow
of electricity.
One of the most common electronic
devices is the transistor. It controls the
flow of electricity by acting as a switch
that can be turned on and off. Transistors
can be very small. Millions of tiny
transistors can be combined into one
device called an integrated circuit. This
allows electronic products to work with
a large number of electric signals very
quickly.
#More to explore
Computer • Electricity • Physics
Element
#see Chemical Element.
Elephant
Elephants are the largest living land animals.
There are three species, or kinds:
the African savanna elephant, the African
forest elephant, and the Asian
elephant. They make up the elephant
family of mammals. Mammoths and
A worker puts together an integrated circuit,
or microchip. Microchips allow electronic
products to work quickly and to be
small in size.
African elephants are the largest of all living
land animals.
BRITANNICA STUDENT ENCYCLOPEDIA Elephant 123
mastodons also belonged to this family,
but they are now extinct.
Where Elephants Live
Elephants live mainly in forests and
grasslands in warm areas. African
elephants live in Africa. The Asian
elephant lives in India, Sri Lanka,
Malaysia, Indonesia, Thailand, and Vietnam.
Physical Features
Elephants’ skin is thick, wrinkled, and
not very hairy. It is grayish to brown in
color. An elephant’s trunk is an extension
of the nose and upper lip. An
elephant uses its trunk to grab food and
to put it into the mouth. It can also
draw water into the trunk and then
blow it into the mouth.
An African elephant has larger ears and a
slightly larger body than an Asian
elephant. African elephants may stand
up to 13 feet (4 meters) at the shoulder.
The Asian elephant may reach about
11.5 feet (3.5 meters) at the shoulder.
Male African and Asian elephants usually
have two tusks, which are long
upper teeth. Female African elephants
have tusks, too, but most female Asian
elephants do not.
Behavior
Elephants migrate, or travel, in search of
food. They eat only plants, including
grasses. They often rest during the hottest
hours of the day. They lie down to
sleep for only a few hours at night.
Elephants move around in small family
groups led by older females, called cows.
A family group has two to eight animals.
Several groups form a herd. A herd
includes as many as 20 to 40 cows and
all their babies. Cows are very protective
of the young in their herd. At about age
4, the male young move away from the
herd. They join separate groups of
males, called bulls.
Life Cycle
A baby elephant is born about 22
months after mating. A newborn
elephant is about 3 feet (1 meter) tall
and weighs about 220 pounds (100 kilograms).
An elephant may live for 60 to
70 years.
Elephants and Humans
Humans have used elephants for transportation
and as work animals since
ancient times. People in Asia still use
elephants for these purposes today. In
An Asian elephant bathes in the Kabani
River in India.
124 Elephant BRITANNICA STUDENT ENCYCLOPEDIA
addition, trained elephants appear in
circuses throughout the world.
However, human activities have endangered
the survival of wild elephants.
Humans have destroyed many elephant
habitats. Humans also have killed many
elephants for the ivory of their tusks.
Humans carve this ivory into works of
art, jewelry, and other objects.
#More to explore
Endangered Species • Mammal
• Mastodon and Mammoth
El Greco
#see Greco, El.
Elizabeth I
Elizabeth I was queen of England for
almost 45 years. During that time her
country became very powerful. Her
reign is remembered as the Elizabethan
Age.
Early Life
Elizabeth was born in Greenwich,
England, on September 7, 1533. Her
father was King Henry VIII. Her
mother, Anne Boleyn, was the second of
Henry’s six wives. Henry had Anne
Boleyn put to death when Elizabeth was
only 3 years old.
Elizabeth had an older half sister named
Mary and a younger half brother named
Edward. Edward became king in 1547
and died in 1553. Mary then became
queen. Henry, Edward, and Elizabeth
were Protestant, but Mary was Roman
Catholic. She made Catholicism the
national religion and put Elizabeth in
prison for a time.
Reign
Mary died in 1558, and Elizabeth was
crowned queen of England. She was 25
years old. She had received a good education
and was well prepared to rule.
Many men wanted to marry her, but she
stayed single. This gave her more power,
but it also put her cousin Mary Stuart
next in line for the throne. Mary Stuart,
