The outside of the earth
We live on the surface of the earth. The surface, or crust of the earth,
is made of rock. In some places, it is covered with soil. In many
places, it is covered with water. All around it is air.
Some of us live on huge pieces of land called continents. A continent is
like a great platform of rock that sticks up a little higher than the
rest of the rocky crust.
Some of us live on smaller pieces of land called islands. An island is
the top of an underwater mountain or part of a continent that has become
separated from the rest of the continent.
The continents and islands where we live are
surrounded by water. Water covers nearly three-fourths of the crust of
the earth. Most of this water lies in enormous pits that are like great
bowls in the rocky crust. These huge “bowls” of water are the oceans.
Water also lies in smaller pits in the continents and islands. These
inland pits of water are lakes and ponds. Water also flows in rivers and
streams, from the high parts of the land down to the lakes and seas.
All around the surface of the earth is a layer of air. This layer of air
is hundreds of miles (kilometers) high. The air is thickest next to the
land and water. It gets thinner the higher it goes. Where the air comes
to an end, outer space begins.
So that’s our earth—a big, spinning, moving ball of rock and hot
metal, with a thin coating of soil, water, and air on the outside.
