football under the famous coach named
PopWarner.
In 1912 Thorpe went to the Olympic
Games in Stockholm, Sweden. He won
gold medals in the decathlon and the
pentathlon. (The decathlon is a trackand-
field competition with 10 events.
The pentathlon has five events.) But in
1913 Thorpe’s medals were taken away
from him. It was found that Thorpe had
played professional baseball in 1909 and
1910. A rule stated that professional
athletes could not participate in the
Olympics.
Thorpe played major league baseball
from 1913 through 1919. Then, from
The “flowers” of a thistle are
actually clusters of many tiny
flowers.
Jim Thorpe was a star player in
the early days of American professional
football.
BRITANNICA STUDENT ENCYCLOPEDIA Thorpe, Jim 61
1919 through 1926, he was an early star
of American professional football. In
1920–21 he served as the first president
of the organization that is now called the
National Football League.
Thorpe died in Lomita, California, on
March 28, 1953. The International
Olympic Committee returned Thorpe’s
Olympic gold medals to his family in
1983.
Tibet
Tibet is a part of western China. It has
some of the world’s tallest mountains.
Tibet is so high that it is often called the
Roof of theWorld. The capital is Lhasa.
Most of Tibet is on a piece of land called
the Plateau of Tibet. The plateau is a
raised flat area about 15,000 feet (4,600
meters) above sea level. The Himalaya
Mountains are to the south. Mount
Everest, the world’s highest peak, is on
the border of Tibet and the country of
Nepal. Tibet’s climate is cold and dry.
Almost all the people of Tibet are Tibetans.
Some Chinese also live there. Tibetans
speak the Tibetan language and
practice their own form of Buddhism.
The main leader of Tibetan Buddhism is
called the Dalai Lama.
The economy of Tibet is based on farming.
Tibetans raise yaks, horses, cows,
sheep, and goats. They grow barley,
wheat, millet, buckwheat, and potatoes.
Tibetans also make handicrafts such as
carpets, blankets, jewelry, and wooden
bowls. A few factories produce textiles,
machinery, chemicals, and other goods.
Tibet became a powerful Buddhist kingdom
between the AD 600s and 800s. It
came under the rule of the Mongols in
the 1200s. In the 1700s the Qing, or
Manchu, Dynasty of China took over
Tibet.
The Qing Dynasty lost power in 1912.
Then the Dalai Lama ruled Tibet. But
in 1950 China again took control. The
Tibetans rebelled against the Chinese in
1959, but they were defeated. The Dalai
Lama fled to India. In the 1960s and
1970s the Chinese closed Buddhist
monasteries and temples and destroyed
The Potala Palace in Tibet was once the
home of the Dalai Lama.
62 Tibet BRITANNICA STUDENT ENCYCLOPEDIA
religious writings. In the 1980s China
began to allow some freedom in Tibet.
#More to explore
Buddhism • China • Dalai Lama
• Himalayas
Tick and Mite
Ticks and mites are tiny animals that are
found all over the world. They are
related to spiders. Many ticks and mites
are parasites. This means that they live
on or inside other animals, which are
called hosts.
Ticks can be more than an inch (2.5
centimeters) long, but most are much
smaller. They can be hard-bodied or
soft. Most hard ticks live in fields or
woods. Soft ticks generally live in the
host’s home or nest.
Mites live in water and soil, on plants,
and as parasites on animals. Some are so
small that people can see them only with
a microscope. Others can be 0.25 inch
(6 millimeters) long.
Ticks and mites develop in stages from
an egg into an adult. Hard ticks start
and end each stage on the ground. At
the end of each stage they attach to a
host, such as a rodent, dog, or person.
They suck the host’s blood for a few
days and then drop to the ground. They
can go months without a meal as they
wait for a host.
Ticks and mites can be very harmful.
They can spread diseases to people, animals,
and plants. For example, the deer
tick carries Lyme disease. Hard ticks can
also give off nerve poisons that can paralyze
or kill the host. Some mites cause
itching and skin problems.
#More to explore
Lyme Disease • Parasite • Spider
Tide
Along the coasts of every ocean on Earth
the water level changes on a regular
basis. This movement is known as the
tide. The greatest height reached as the
water rises is known as high tide. The
lowest level reached as the water falls is
known as low tide.
Tides take place in all bodies of water. In
some waters, however, the change is so
slight that tides go unnoticed. Tides are
easier to see where an ocean meets land
along seacoasts and in bays. There are
An American dog tick perches on grass
while it waits for a chance to attach itself to
a dog or other mammal. The American dog
tick can give humans a serious disease
called Rocky Mountain spotted fever.
BRITANNICA STUDENT ENCYCLOPEDIA Tide 63
usually two high and two low tides per
day at any given place. The times at
which they happen, however, change
from day to day. The average amount of
time between two high tides is 12 hours
and 25 minutes.
Tides are caused by a natural force
called gravity. Because of gravity, all
bodies in the universe pull on each
