Robert Willis age 10, of Tulsa, OK 

How did the earth get its air?

Many experts think that the earth has been blanketed with air since the very beginning. If the solid earth cooled from a blazing ball of fire, as some suppose, a cloak of cloudy gases may have clung to the steaming globe maybe four billion years ago. The gases, however, have changed with time and are still changing.

Plant life poured oxygen into the air, animal life added carbon dioxide and this process is still going on. The sea adds steamy vapor and volcanoes from time to time add gases from deep in the ground. And the deep, filmy cloak of air around the globe is hugged by the pull of earths gravity ‑ which prevents it from leaving us to sail off into space.