Overview of Earth

Earth is where we all live. 

It is our home in the solar system. There is no other place for us to live. /ɜːθ/

Earth isn’t just any planet. It’s a veryspecial place. It’s special because we depend on it for many things.

Because of its importance we need to takecare of it.

We depend on the earth for its air, itswater and many of its natural resources.

Natural resources, such as coal and oil, give us energy. Other natural resources we depend on

include forests and soil  /ˈnætʃ(ə)rəl/    /kəʊl/   /sɔɪl/

Forests provide clean air and wood for building houses. Soil is needed to grow plants and keep them healthy. Weneed to take care of these resources and not waste them.

The earth is a large, rotating sphere, about 4.5 billion years old. /rəʊˈteɪtɪŋ/

The equator which divides the earth into two hemispheres, is about 40,000 kilometers long. 4万。/ɪˈkweɪtə(r)/ /kɪˈlɒmɪtə(r)

The Earth's diameter is 12,756 kilometers. 直径/daɪˈæmɪtə(r)/

Its radius is half that, or 6,378 kilometers. /ˈreɪdiəs/

The radius is the distance from the Earth’s center to its surface. /ˈsɜːfɪs/

Most of the Earth’s surface is covered by water. The rest of the Earth’s surface is land.

Just above the Earth's surface is the atmosphere. /ˈætməsfɪə(r)/

The atmosphere is a layer of gases, about 500 kilometers thick. /θɪk/

These gases included oxygen, nitrogen and carbon dioxide. 氧气、氮气和二氧化碳。/ˈnaɪtrədʒən/ /ˌkɑːbən daɪˈɒksaɪd/

This mixture of gases is the air that we breathe. /briːð/

As we move above the Earth’s surface, the air gets thinner.

At high altitudes, the air is too thin to breathe. /ˈæltɪtuːd/

At the edge of theatmosphere is space. There is no air at all in space.