in the 1600s, namely Galileo and Isaac
Children study different types of mathematics
at school. One of the first types they
learn is basic arithmetic—adding, subtracting,
multiplying, and dividing.
Workers look at the plans for a building.
The use of mathematics to construct buildings
is an example of applied math.
BRITANNICA STUDENT ENCYCLOPEDIA Mathematics 77
Newton, applied math to the study of
motion. In the 1800s and 1900s scholars
developed many new ways to study
and use math.
#More to explore
Arithmetic • Geometry • Numbers and
Number Systems • Statistics
Matter
Anything that takes up space is called
matter. Air, water, rocks, and even
people are examples of matter. Different
types of matter can be described by their
mass. The mass of an object is the
amount of material that makes up the
object. A bowling ball, for example, has
more mass than a beach ball.
States of Matter
Matter exists in several different forms,
called states. The three most familiar
states are solid, liquid, and gas.
Rocks, books, desks, and balls are
examples of solids. Matter in the solid
state has a set size and shape. A solid’s
size and shape do not change easily. For
example, when a person moves a book
from a smaller to a bigger box, the book
looks the same.
Milk and water are examples of liquids.
In the liquid state, matter has a set size,
or amount. However, its shape depends
on its container. For example, milk
changes shape when a person pours it
from a carton into a glass. But the
amount of milk stays the same.
The air and the helium used to fill balloons
are examples of gases. Matter in
the gaseous state does not have either a
set size or a set shape. It can expand to
fill a large container, or it can be
squeezed into a smaller container.
Matter can change from one state to
another. For example, heat causes ice
(solid water) to melt into a liquid. Heat
also causes liquid water to evaporate, or
turn into water vapor—a gas.
Properties of Matter
All matter has physical properties. A
physical property is one that a person
can measure without changing the matter.
Color, amount, and temperature are
examples of physical properties.
All matter also has chemical properties.
A chemical property tells how matter
will change under special conditions.
For example, certain metals turn to rust
if they sit out in the rain. Paper and
wood burn to ashes if they touch a
flame. Burning and rusting are called
chemical reactions. Chemical reactions
change matter into new types of matter.
The three most familiar states of matter are
solid, liquid, and gas. Water exists in all
three states.
78 Matter BRITANNICA STUDENT ENCYCLOPEDIA
Mauritania
Mauritania, a country inWest Africa,
lies in the huge desert called the Sahara.
Its capital is Nouakchott.
Geography
Mauritania shares borders withWestern
Sahara, Algeria, Mali, and Senegal. The
Senegal River forms part of the southern
border. The Atlantic Ocean is to the
west. Most of the land is flat. Sand
dunes cover about half of the country.
Plants and Animals
The northern part of Mauritania is a
desert with few plants. The savanna, or
grassland, in the south has baobab and
palm trees. Lions, elephants, ostriches,
and panthers live on the savanna.
People
Most of the people are Moors. These are
the descendants of Arabs and Berbers
(the original inhabitants of North
Africa). Black Africans make up the rest
of the population. The main language is
Arabic. Islam is the national religion.
More than half of the people live in cities
or towns. But many people follow a
nomadic (wandering) lifestyle.
Economy
Mining, fishing, and farming are important
parts of Mauritania’s economy. Iron
ore and fish are valuable exports. In the
early 21st century Mauritania also
started to export oil. Many of Mauritania’s
people raise sheep, goats, cattle, or
camels. Rice, millet, sorghum, beans,
and dates are major crops.
History
The first people in what is now Mauritania
were black African and Berber
peoples. Arab tribes moved into the area
in the 1400s. France set up settlements
in the 1800s. In 1920 the area became a
French colony. Mauritania gained independence
in 1960.
A woman paints the wall of her house in
Mauritania.
Facts About
MAURITANIA
Population
(2008 estimate)
3,204,000
Area
398,000 sq mi
(1,030,700 sq
km)
Capital
Nouakchott
Form of
government
Republic
Major cities
Nouakchott,
Nouadhibou,
Rosso, Boghe,
Adel Bagrou
BRITANNICA STUDENT ENCYCLOPEDIA Mauritania 79
Mauritius
Mauritius is a small island country off
the southeast coast of Africa. Mauritius’
capital is Port Louis.
Geography
Mauritius lies in the Indian Ocean
about 500 miles (800 kilometers) east of
Madagascar. The country includes the
large island called Mauritius as well as
several smaller islands.
Plants and Animals
Most of Mauritius’ forests were cut
down to make room for sugar plantations.
Its remaining plants include bamboo,
coconut palms, and ebony trees.
The country’s unique wildlife includes
the samber (a long-tailed deer) and the
tenrec (a spiny mammal). A large bird
called the dodo once lived in Mauritius,
but the last dodo died before 1681.
People
Most Mauritians have roots in southern
