How much of the Earth is covered by oceans?

Seventy percent
of Earth’s surface area
is ocean water.

Sixth U.S. President

John Quincy Adams
was the sixth President of
the United States.

Area of a square

The area of
a square equals the square of
the length of one side.

Land below sea level

Thirty-three countries
on Earth have some land that is
below sea level.

Astronomical unit

Astronomical
unit:  mean distance between
the Earth and the Sun.