Sixth Grade
Worksheets
Planet Earth
Caption: From space, Earth looks like a blue marble with its swirling white clouds, deep blue oceans, and brown land masses with traces of green vegetation. Photo credit: NASA
Earth is our home, but it is also a planet speeding through space like a giant spaceship as it orbits the sun. If aliens from another solar system came to visit our home planet, they might think it was misnamed. Earth means land or soil, but seventy-one percent of our planet is covered with beautiful blue water. Land makes up only a little less than thirty percent of our planet's surface. Earth is unique among all the other planets of our solar system. No other planet that we know of has bodies of liquid water on its surface. Liquid water has made life on Earth possible.
Earth is one of four terrestrial planets, so named for their resemblance to Earth. (Terra is the Greek word for "earth.") Mercury, Venus, and Mars are believed to be similar to Earth in composition: rocky crusts with mostly metal cores. The four outer planets have different compositions; they are gas giants without solid surfaces.
